ENGINE CONTROL

SECTION EC
CONTENTS
PRECAUTIONS .................................................. EC-3 Ignition Timing Adjustment:
On Board Diagnostic (OBD) System of Change the adjustment value from 5 dec
Engine ............................................................ EC-3 to 0 dec, and then adjust ignition timing. ...... EC-49
Precaution ...................................................... EC-3 Fuel Pressure Clear:
PREPARATION .................................................. EC-6 Perform (Cancel) fuel pressure clear. .......... EC-50
Special Service Tools ..................................... EC-6 Power Balance:
DESCRIPTION .................................................... EC-7 Stop No. 3 cylinder in power balance. .......... EC-51
Description ..................................................... EC-7 Self-diagnosis Clear:
Component Parts Location ........................... EC-12 Perform (Cancel) self-diagnosis. .................. EC-52
ECM Component .......................................... EC-13 BASIC INSPECTION ........................................ EC-53
Circuit Diagram ............................................. EC-16 Inspection of Idle Speed and
TROUBLE DIAGNOSIS .................................... EC-17 Ignition Timing.............................................. EC-53
ECM Terminal/Input/Output Signal Throttle Valve Closed Position Learning
Specification ................................................. EC-17 and Idle Air Volume Learning ....................... EC-54
How to Proceed with Trouble Diagnosis ...... EC-24 Accelerator Pedal Released
Diagnosis Chart by Symptom ....................... EC-25 Position Learning ......................................... EC-55
Description .................................................. EC-32 Fuel Pressure Inspection .............................. EC-55
Fail-Safe Function ....................................... EC-32 Accelerator Pedal Released
TABLE OF DIAGNOSIS TROUBLE Position Learning ......................................... EC-56
CODE (DTC) ............................................... EC-33 COMPONENT PARTS INSPECTION ............... EC-57
Service Tool ................................................ EC-41 Crankshaft Position Sensor (POS) ............... EC-57
Self-Diagnosis Function Camshaft Position Sensor (PHASE) ............ EC-57
(Without Service tool) .................................. EC-43 Mass Air Flow Sensor .................................. EC-57
ECM Input/Output Monitor Engine Coolant Temperature Sensor ........... EC-57
Reference Data ............................................ EC-44 Throttle Position Sensor 1, 2
ECM Active Test ........................................... EC-45 (Electric throttle control actuator assembly) . EC-58
Idle Air Volume Learning: COMPONENT PARTS INSPECTION ............... EC-58
Perform (Cancel) Idle Air Volume Learning Accelerator Pedal Position Sensors 1, 2
(Normal). ...................................................... EC-46 (Accelerator work unit) ................................. EC-58
Air-fuel Ratio Adjustment: Intake Air Temperature Sensor
Change the adjustment value from 85 dec (Joined with mass air flow sensor) ............... EC-59
to 100 dec, and then adjust air-fuel ratio. ..... EC-47 Stop Light Switch ......................................... EC-59
Learned Air-fuel Ratio Value: Spark Plug .................................................... EC-59
Clear (Cancel) learned air-fuel ratio value. ... EC-48 Ignition Coil .................................................. EC-60
Gasoline Injector .......................................... EC-60
Fuel Pump .................................................... EC-61
 CONTENTS (Cont'd)
Electric Throttle Control Motor
(Electric throttle control actuator assembly) . EC-61
Heated Oxygen Sensor ................................ EC-61
LPG Injector ................................................. EC-62
LPG Assistance Injector ............................... EC-62
PTC Heater (Integrated with vaporizer) ....... EC-62
A/C System .................................................. EC-62
PCV GAS RECIRCULATION DEVICE ............. EC-63
System Diagram ........................................... EC-63
Component Parts Inspection ........................ EC-63
ECM COMPONENTS ........................................ EC-64
Removal and Installation .............................. EC-64

NOTE: This section contains information and

specifications for both carbureted general
overseas market models, as well as,
electronic control models (manufactured
in USA.) Therefore, ensure the
specifications or procedures you are
looking at are for the proper fuel delivery
system; electronic controlled or
carbureted.
 PRECAUTIONS

PRECAUTIONS On Board Diagnostic (OBD) System of

Engine
The ECM has an on board diagnostic system. It will light up the
malfunction indicator light (MIL) to warn the driver of a malfunction
causing emission deterioration.

CAUTION:
• Be sure to turn the ignition switch OFF and disconnect the
negative battery cable before any repair or inspection
work. The open/short circuit of related switches, sensors,
solenoid valves, etc. will cause the MIL to light up.
• Be sure to connect and lock the connectors securely after
work. A loose (unlocked) connector will cause the MIL to
light up due to the open circuit. (Be sure the connector is
free from water, grease, dirt, bent terminals, etc.)
• Certain systems and components, especially those related
to OBD, may use a new style slide-locking type harness
connector.
• Be sure to route and secure the harnesses properly after
work. The interference of the harness with a bracket, etc.
may cause the MIL to light up due to the short circuit.
• Be sure to connect rubber tubes properly after work. A
misconnected or disconnected rubber tube may cause the
MIL to light up due to the malfunction of fuel injection
system, etc.
• Be sure to erase the unnecessary malfunction information
(repairs completed) from the ECM before returning the
vehicle to the customer.

Precaution
• Always use a 12 volt battery as power source.
• Do not attempt to disconnect battery cables while engine is
running.
• Before connecting or disconnecting the ECM harness
connector, turn ignition switch OFF and disconnect battery
ground cable. Failure to do so may damage the ECM
because battery voltage is applied to ECM even if ignition
switch is turned OFF.
• Before removing parts, turn ignition switch OFF and then
disconnect battery ground cable.
SEF0289H

• Do not disassemble ECM.

• If a battery cable is disconnected, the memory will return to
the ECM value. The ECM will now start to self-control at its
initial value. Engine operation can vary slightly when the
terminal is disconnected. However, this is not an indication
of a malfunction. Do not replace parts because of a slight
variation.
• If the battery is disconnected, the following emission-
related diagnostic information will be lost within 24 hours.
– Diagnostic trouble codes
– 1st trip diagnostic trouble codes

EC-3
 PRECAUTIONS

Precaution (Cont’d)
• When connecting ECM harness connector, fasten it
securely with levers as far as they will go as shown in the
figure.

• When connecting or disconnecting pin connectors into or

from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.
• Securely connect ECM harness connectors. A poor
connection can cause an extremely high (surge) voltage to
develop in coil and condenser, thus resulting in damage to
ICs.
• Keep engine control system harness at least 10 cm (4 in)
away from adjacent harness, to prevent engine control
system malfunctions due to receiving external noise,
degraded operation of ICs, etc.
• Keep engine control system parts and harness dry.
• Before replacing ECM, perform ECM Terminals and
Reference Value inspection and make sure ECM functions
properly.
• Handle mass air flow sensor carefully to avoid damage.
• Do not disassemble mass air flow sensor.
• Do not clean mass air flow sensor with any type of
detergent.
• Do not disassemble electric throttle control actuator.
• Even a slight leak in the air intake system can cause
serious incidents.
MEF040D • Do not shock or jar the camshaft position sensor (PHASE),
crankshaft position sensor (POS).
• After performing each TROUBLE DIAGNOSIS, perform DTC
Confirmation Procedure or Overall Function Check.
The DTC should not be displayed in the DTC Confirmation
Procedure if the repair is completed. The Overall Function
Check should be a good result if the repair is completed.

EC-4
 PRECAUTIONS

Precaution (Cont’d)
• When measuring ECM signals with a circuit tester, never
allow the two tester probes to contact. Accidental contact
of probes will cause a short circuit and damage the ECM
power transistor.
• Do not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the
ECM's transistor. Use a ground other than ECM terminals,
such as the ground.

SEF348N

• Do not operate fuel pump when there is no fuel in lines.

• Tighten fuel hose clamps to the specified torque.

• Do not depress accelerator pedal when starting.

• Immediately after starting, do not rev up engine
unnecessarily.
• Do not rev up engine just prior to shutdown.

SEF709Y

EC-5
 PREPARATION

PREPARATION Special Service Tools

Description Application
EGI fuel pressure indicator For measuring fuel pressure gauge
ST19590000

ECM0013

Heated oxygen sensor wrench Removing and installing heated oxygen

KV10113700 sensor

ECM0014

Check adapter V For control unit input/output signal inspection

EG1755000 (for SMJ 150-pin connector)

ECM0016

Harness adapter
EG17550200
(150-pin to 121-pin conversion adapter)

ECM0017

EC-6
 DESCRIPTION

DESCRIPTION Description
• Adopts Electronic Concentrated engine Control System
(ECCS). Fuel injection control, ignition timing control, idle speed
control, and electronically controlled governor control etc. are all
performed by a single control unit.
• Adopts electric throttle control actuator system to control
electronically controlled governor.
• Adopts Hall IC type crankshaft position sensor (POS) and
camshaft position sensor (PHASE).
Items Description
Electric throttle control actuator • Adopts electronic throttle control actuator with integrated throttle control motor to adjust
throttle valve opening optimally according to driving conditions or to improve safety and
operability by electronically controlled governor.
Fuel injection control • With fuel injection control, air-fuel ratio is optimized to improve exhaust performance and
response.
• Using feedback control through learning of air-fuel ratio compensation, the system corrects
the ratio during transitional conditions, such as sudden sharp changes in the ratio, in order
to improve drivability.
Ignition timing control • Uses Hall IC crankshaft position sensor (POS) and camshaft position sensor (PHASE) to
perform controls so that optimum ignition timing is obtained for every operating condition.
Optimum ignition timing setup according to each fuel is also enabled at the time of a
combined use formula.
• Adopts electronic distribution system (NDIS) in which each cylinder is equipped with an
ignition coil incorporating a power transistor for better ignition performance.
Idle speed control • Adopts electronic throttle control actuator that continuously regulates intake air amount
required for idling.
Governor speed control • Performs maximum regulation of engine speed for oil pressure pump protection by engine
speed signal.
Maximum speed regulation control • Performs maximum speed regulation by vehicle speed sensor signal. Also, performs
variable control of maximum speed by changeover switch.
Idling area torque up control • Performs torque up control in idling area by engine speed signal in order to also enable
cargo work at idling.
Overheat prevention control • Reduces engine heat generation by reducing maximum engine speed and regulating
maximum throttle opening when engine coolant temperature reaches approximately 110°C
(230°F).
• Prevents resulting in engine breakage by overheat by performing fuel cut at 1,000 rpm or
more when engine coolant temperature reaches approximately 135°C (275°F).
• Transmission overheat control; Reduce engine revolution when the transmission overheat
switch (122 °C is detected. Transmission overheat switch via VCM. ECM reduce engine
rpm to 1600.
Power/ECO mode control • Changes throttle opening characteristic of throttle position by power/ECO mode control
switch, and then minute operation of engine speed is enabled. (Option setting)
Fuel pump control (gasoline) • Turns fuel pump relay ON/OFF depending on engine speed signal.
LPG interception valve control • Turns interception valve relay ON/OFF depending on engine speed signal and fuel
pressure sensor signal.
Fail-safe function • Ensures vehicle's safe operation and enables vehicle to be driven in an emergency when
any of the major system components (mass air flow sensor, engine coolant temperature
sensor, etc.) have malfunctioned.
Diagnostic system • Adopts self-diagnosis system for easier trouble diagnosis.
Oil pressure control • Reduce engine revolution when the oil pressure low (approx. 0.2 bar) is detected for more
than 5 seconds; ECM reduce rpm; Oil pressure switch via Meter panel; ECM reduce
engine rpm to 1600.

EC-7
DESCRIPTION

Description (Cont’d)
K-ENGINE ELECTRONIC CONTROLLED SYSTEM DIAGRAM (GASOLINE)

EC-8
DESCRIPTION

Description (Cont’d)
K-ENGINE ELECTRONIC CONTROLLED SYSTEM DIAGRAM (LPG)

EC-9
DESCRIPTION

Description (Cont’d)
K-ENGINE ELECTRONIC CONTROLLED SYSTEM DIAGRAM
(COMBINED USE)

EC-10
 DESCRIPTION

Description (Cont’d)
SENSORS AND ACTUATORS CONTROL ITEMS
Main sensors and actuators related to the ECM are listed below.

Combined
Gasoline std std std std std std std std opt std std

Fuel

Fuel changing (Gasoline and LPG) Combined

LPG std std std — std std std std opt std std

Control Item Fuel injection

control

Maximum vehicle speed control

Maximum engine speed control

Power ECO mode control

Ignition timing control
Fuel injection control

A/F feedback control

Fuel pump control

Idle speed control

Self-diagnosis
Fuel cut off

Fail-safe
: Significant impact to control
: Impact to control

Crankshaft position sensor (POS, PHASWE)

Mass air flow sensor
Intake air temperature sensor
Engine coolant temperature sensor
Heated oxygen sensor
Vehicle speed sensor
Throttle position sensor
Accelerator pedal position sensor
Sensors

Ignition switch
P/N POSI SW
Stop light switch
Headlight (electrical load) switch
Power ECO mode switch (opt)
Battery voltage
LPG fuel pressure sensor
Fuel changing switch
Gasoline injector
Power transistor
Ignition system
Ignition coil
Throttle control motor relay
Throttle control motor
Gasoline fuel pump relay
Actuators

Gasoline fuel pump

Ignition relay
ECM relay
LPG injector
LPG assistance injector
LPG interception valve relay
LPG interception valve

EC-11
 DESCRIPTION

Description (Cont’d)

Component Parts Location

Specifications
Main component part Type Location
Gasoline LPG Combined

Actuators Gasoline injector High resistance Intake manifold

LPG injector Gas injection Integrated in injector
holder (on intake
manifold)
Fuel pump Electric motor/turbine Integrated in fuel tank
Fuel pressure regulator Diaphragm
Throttle control motor Electric DC motor (DC Integrated in electronic
motor) throttle control actuator
Ignition coil Mold (built-in power Cylinder head (On each
transistor) spark plug)

EC-12
 DESCRIPTION

Description (Cont’d)

Component Parts Location (Cont’d)

Specifications
Main component part Type Location
Gasoline LPG Combined

Sensors Crankshaft Crankshaft Hall IC (element) Front cover

position position sensor
sensor (POS)
Camshaft position Chain housing
sensor (PHASE)
Mass air flow sensor Hot wire Air horn
Accelerator pedal position Variable resistance Integrated in accelerator
sensors 1 and 2 work unit (accelerator
pedal assembly)
Throttle position sensors 1 and 2 Integrated in electronic
throttle control actuator
Engine coolant temperature Thermistor Water outlet
sensor
Intake air temperature sensor With air flow meter
Heated oxygen sensor Zirconia (with heater) Exhaust manifold
ECM 121-pin digital control Vehicle side
ECM & IGN coil relay Compact general relay Vehicle side
(1M X 2)

ECM Component
Specifications NOTE
Component Location
Gasoline LPG Combined Actuator Sensor Other
Gasoline injector Intake manifold
LPG injector Integrated in injector holder (on
intake manifold)
Throttle control motor Integrated in electronic throttle
Throttle position sensors 1 and 2 control actuator
Ignition coil Cylinder head (on each spark plug)
Crankshaft position sensor (POS) Front cover
Camshaft position sensor (PHASE) Front housing
Mass air flow sensor Air horn
Intake air temperature sensor With air flow meter
Engine coolant temperature sensor Water outlet
Accelerator pedal position sensors Integrated in accelerator work unit
1 and 2 (accelerator pedal assembly)
Fuel pump Integrated in fuel tank
Fuel pressure regulator
Heated oxygen sensor (Vehicle side)
Vehicle speed sensor (Vehicle side)
ECM (Vehicle side)
ECM & IGN coil relay (Vehicle side)
Stop light switch (Vehicle side)
Throttle control motor relay (Vehicle side)
Fuel pump relay (Vehicle side)
Vaporizer (Vehicle side)
LPG interception valve (Vehicle side)

EC-13
DESCRIPTION

Description (Cont’d)

ECM Component (Cont’d)

EC-14
DESCRIPTION

Description (Cont’d)

ECM Component (Cont’d)

EC-15
DESCRIPTION

Description (Cont’d)

Circuit Diagram
K-ENGINE ELECTRONIC CONTROLLED ECM CIRCUIT DIA-
GRAM (COMBINED GASOLINE AND LPG)

EC-16
 TROUBLE DIAGNOSIS

TROUBLE DIAGNOSIS ECM Terminal/Input/Output Signal

Specification

ECM INPUT/OUTPUT SIGNAL SPECIFICATIONS

Voltage is measured with a circuit tester, and the sample waveforms
obtained with an oscilloscope are shown below for each ECM
terminal. Measurement data varies depending on variation in parts
as well as many other factors. Such factors include vehicle history,
driving conditions, environmental conditions, maintenance status,
measuring instrument/method, etc. Data shown below are reference
values.
Terminal
Description Measurement condition Measured value
signal
1 ECM ground Always Approx. 0V
2
115
116
66 Sensor ground (Throttle position sensor) At idle after warming up Approx. 0V
At approx. 2,000 rpm
67 Mass air flow sensor ground Always Approx. 0V
78 Heated oxygen sensor ground Always Approx. 0V
82 Accelerator pedal position sensor 1 Always Approx. 0V
ground
83 Accelerator pedal position sensor 2 Always Approx. 0V
ground
32 Fuel changing switch 2 (Gasoline) Changing switch ON (At gasoline side) Approx. 5V
Changing switch ON (At LPG side) Approx. 0V
56 Governor control switch At normal speed setting Approx. 0V
At low speed setting Battery voltage
70 Fuel changing switch 1 (LPG) Changing switch ON (At LPG side) Approx. 5V
Changing switch ON (At GAS side) Approx. 0V
84 Headlamp switch Lighting switch OFF Approx. 0V
Lighting switch ON Battery voltage
101 Brake switch Brake pedal released Approx. 0V
Brake pedal depressed Battery voltage
102 Neutral switch N position Approx. 0V
Other than above Battery voltage
109 (IGN) Ignition switch Ignition switch OFF Approx. 0V
Ignition switch ON Battery voltage
100 A/C switch A/C switch ON (At engine running) Approx. 0V
105 A/C relay A/C switch ON (At engine running) Approx. 12V

EC-17
 TROUBLE DIAGNOSIS

ECM Input/Output Signal Specification

(Cont’d)

Terminal
Description Measurement condition Measured value
signal
13 Crankshaft position sensor (POS) At cranking Approx. 2.6V

ECM0052

At idle after warming up Approx. 3V

ECM0053

At approx. 2,000 rpm Approx. 3V

ECM0054

14 Camshaft position sensor (PHASE) At cranking Approx. 0.15V

ECM0055

At idle after warming up Fluctuates between approx. 1.5 - 2V.

ECM0056

At approx. 2,000 rpm Approx. 2V

ECM0057

24 Heated oxygen sensor heater At idle after warming up Approx. 0.3V

31 LPG fuel pressure sensor At idle after warming up Approx. 0.78V

EC-18
 TROUBLE DIAGNOSIS

ECM Input/Output Signal Specification

(Cont’d)

Terminal
Description Measurement condition Measured value
signal
35 Heated oxygen sensor At idle after warming up Changes between approx. 0.1 -
0.4V ;approx. 0.6 - 0.9V

ECM0058

At approx. 2,000 rpm Changes between approx. 1 -

0.4V ;approx. 0.6 - 0.9V

ECM0059

50 Throttle position sensor 1 At idle after warming up Approx. 0.6V

Ignition switch ON with engine stopped Approx. 0.5V
Accelerator pedal is fully depressed
Ignition switch ON with engine stopped Approx. 4.3V
Accelerator pedal is released
At approx. 2,000 rpm Approx. 0.7V
51 Mass air flow sensor Ignition switch ON Approx. 1V
At cranking Approx. 1.5V
At idle after warming up Approx. 1.3V
At approx. 2,000 rpm Approx. 1.5V
69 Throttle position sensor 2 At idle after warming up Approx. 4.5V
Ignition switch ON with engine stopped Approx. 4.5V
Accelerator pedal is fully depressed
Ignition switch ON with engine stopped Approx. 0.7V
Accelerator pedal is released
At approx. 2,000 rpm Approx. 4.4V

EC-19
 TROUBLE DIAGNOSIS

ECM Input/Output Signal Specification

(Cont’d)

Terminal
Description Measurement condition Measured value
signal
98 Accelerator pedal position sensor 2 At Idle Approx. 0.335 - 0.435V
Ignition switch ON with engine stopped Approx. 0.335 - 0.435V
Accelerator pedal is fully depressed
Ignition switch ON with engine stopped Approx. 2.2 - 2.3V
Accelerator pedal is released
At approx. 2,000 rpm Approx. 0.35V
106 Accelerator pedal position sensor 1 At Idle Approx. 0.67 - 0.87V
Ignition switch ON with engine stopped Approx. 0.67 - 0.87V
Accelerator pedal is fully depressed
Ignition switch ON with engine stopped Approx. 4.4 - 4.6V
Accelerator pedal is released
At approx. 2,000 rpm Approx. 0.65V
27 PTC heater relay At idle after warming up Approx. 0V
(Except north america) Ignition switch ON when the engine Battery voltage
coolant temperature is 30°C (86°F) or
less (except for cranking)
104 Throttle control motor relay Ignition switch ON, engine running Approx. 1V
112 LPG interception valve relay Engine running Battery voltage
Ignition switch OFF Approx. 0V
113 Gasoline F/P relay For approximately 1 second after ignition Approx. 1V
switch ON
After that Battery voltage
At cranking, engine running Approx. 1V
3 Throttle control motor relay power supply Always Battery voltage
48 Sensor power supply Ignition switch ON, engine running Approx. 5V
49 Fuel changing switch power supply Changing switch ON Approx. 5V
Changing switch ON (At neutral) Approx. 0V
90 Accelerator pedal position sensor 1 Ignition switch ON, engine running Approx. 5V
power supply
91 Accelerator pedal position sensor 2 Ignition switch ON, engine running Approx. 2.5V
power supply
110 Power supply for ECM (backup) Always Battery voltage
118 Power supply for ECM Ignition switch ON, engine running Battery voltage
121
4 Throttle control motor (Close) At idle after warming up Approx. 2 - 2.5V
At approx. 2,000 rpm
5 Throttle control motor (Open) At idle after warming up Approx. 0.1 - 0.15V
At approx. 2,000 rpm
11 LPG assistance injector At idle after warming up Battery voltage

EC-20
 TROUBLE DIAGNOSIS

ECM Input/Output Signal Specification

(Cont’d)

Terminal
Description Measurement condition Measured value
signal
22 Injector drive signal At cranking Approx. 10.5V
23
41
42

ECM0060

At idle after warming up Battery voltage

ECM0061

At approx. 2,000 rpm Relatively lower than battery voltage

ECM0062

34 Intake air temperature sensor signal Intake air temperature is approx. 20°C Approx.
(68°F). 3.5V

Intake air temperature is approx. 80°C Approx.

(176°F). 1.2V

ECM0499

47 Electric throttle control actuator open Ignition switch ON, engine running Approx. 5V

EC-21
 TROUBLE DIAGNOSIS

ECM Input/Output Signal Specifications

(Cont’d)

Terminal
Description Measurement condition Measured value
signal
61 Ignition signal (power transistor drive At cranking Approx. 0.2V
62 signal)
80
81

ECM0047

At idle after warming up Approx. 0.1V

ECM0048

At approx. 2,000 rpm Approx. 0.1V

ECM0049

73 Engine coolant temperature sensor Engine coolant temperature is approx. Approx.

signal 20°C (68°F). 3.5V

Engine coolant temperature is approx. Approx.

80°C (176°F). 1.2V

ECM0500

85 (K LINE) Signal line for service When connected to Service tool Approx. 6.6 - Battery voltage
When not connected to Service tool Approx. 6V
86 CAN communication line L Always Approx. 2.2V (Varies depending on
communication status.)

ECM0051

EC-22
 TROUBLE DIAGNOSIS

ECM Input/Output Signal Specifications

(Cont’d)

Terminal
Description Measurement condition Measured value
signal
94 CAN communication line H Always Approx. 2.4V (Varies depending on
communication status.)

ECM0050

111 Self shut-off For approximately 10 seconds with Approx. 1V

ignition switch ON and after ignition
switch OFF
Approximately 10 seconds on more after Battery voltage
ignition switch OFF
119 LPG injector drive (H) Battery voltage
Time axis may change according to
setting data and driving condition.

120 LPG injector drive (L) Battery voltage

Time axis may change according to
setting data and driving condition.

NOTE:
Numerical values are obtained using an analog circuit tester.

EC-23
 TROUBLE DIAGNOSIS

How to Proceed with Trouble Diagnosis

1. The most important point in performing trouble diagnosis of
malfunctions is to thoroughly understand the vehicle systems
(both control and mechanical).
An ECM-based engine controls actuators such as injectors and
the ignition coil according to information from sensors. Then
through actuator operation, the engine (mechanical system)
runs. Sensors transmit information on the running condition,
which changes constantly, to ECM. It is important to under-
stand these cycles.
ECM0031

2. It is also important to clarify customer concerns before starting

the inspection.
First of all, reproduce the symptom, and understand it fully.
Ask the customer about his/her concerns carefully. In some
cases, it will be necessary to check the symptoms by driving
the vehicle with the customer.

CAUTION:
Customers are not professionals. Do not assume “maybe the
customer means ...” or “maybe the customer mentioned this
ECM0032 symptom”.
3. It is essential to confirm symptoms right from the beginning in
order to ensure all malfunctions are completely repaired.
For an intermittent malfunction, it is important to reproduce the
symptom based on an interview with the customer and past
examples. Do not perform an inspection on an ad hoc basis.
Most intermittent malfunctions are caused by poor contacts. In
this case, it will be effective to shake the suspected harness or
connector by hand. When repairs are performed without any
symptom check, no one can judge if the malfunction has actu-
ally been eliminated.
ECM0033
4. The next important thing is to find which system among the
following is causing the malfunction: ECM control signal
system, or a mechanical system (such as the engine main body
and auxiliary component). It is important to inspect the system
using Service tool or by checking the ECM input/output signals.
When checking the ECM input/output signals, connect a check
adapter (Service tool) to ECM in order to prevent misdiagnosis.
Special Service Tools (Service tool):
Check adapter V (EG17530000) (for SMJ 150-pin con-
nector)
Harness adapter (EG17550200) (150-pin 121-pin
conversion adapter)
5. Use the reference value of input/output data (guideline) in this
manual in order to judge the ECM input/output signals. Measure
the data of another vehicle of the same model under the same
conditions when it is difficult to judge, and compare the data. It
is advisable to collect sufficient data of a normally operating
vehicle.

ECM0034

EC-24
 TROUBLE DIAGNOSIS

How to Proceed with Trouble Diagnosis

(Cont’d)
TROUBLE DIAGNOSIS FLOW CHART
There are many different malfunction symptoms. So there is no
perfect trouble diagnosis technique applicable to all malfunctions.
Experience is also important to achieving an accurate trouble
diagnosis.
Nonetheless, an accurate trouble diagnosis can be performed by
applying similar procedures, regardless of the malfunction symptom.
Perform trouble diagnosis following the flow chart shown below.

ECM0035

DIAGNOSTIC WORK SHEET

Description
• In order to clarify the malfunction symptom, it is important to ask
the customer and collect information about their concerns.
• Ask the customer about what symptoms are present under what
conditions. Use the information to clarify the symptom.
• Use the trouble diagnosis sheet to be certain not to miss any
vital information.

ECM0036
Diagnosis Chart by Symptom
RELATIONSHIP BETWEEN MALFUNCTIONING SYMPTOMS
AND THE SENSOR CIRCUIT

EC-25
 TROUBLE DIAGNOSIS

The table below shows the possible symptoms caused by the

malfunction of each sensor circuit.

Poor starting

Check that symptoms are detected with self-diagnosis.

Impossible
to start
Engine

Other
Symptoms Poor idle Poor driving control

Check that symptoms are in fail-safe condition.

stall

During surge and constant speed driving

Engine rpm does not increase smoothly.
Inconsistent idle when engine is cold.

Engine over temperature (Overheat)

Inconsistent idle when warming up

Poor fuel consumption efficiency

During surge and acceleration
When engine is warming up
Fast idle is not effective Description/notable
No initial combustion

characteristics of the
When engine is cold

During a heavy load

During deceleration
Poor power output
Initial combustion

Poor acceleration
symptom
High idle rpm
Low idle rpm

After-burn
Knocking
Backfire

Driving
At Idle
Sensor malfunction
: Highly possible
: Possible

Crankshaft position sensor OPEN • An open circuit in either REF or

(POS, PHASE) POS signal makes it impossible
for the vehicle to start.
• Control signals for fuel system
and ignition system are not
output.

Momentarily • The symptom depends on the

open duration of momentarily open
circuit and the operating
conditions. Slight shocks and
surges may be sensed during
driving, while engine stall may
be caused during idle.

Mass air flow Signal OPEN • It will be in fail-safe condition,

sensor and vehicle runs at an engine
speed from 800 rpm to 1,600
rpm.

High output • The air-fuel ratio becomes rich.

Black smoke may accompany.
Poor connection of grounding
may be a possible cause.

Low output • The air-fuel ratio becomes lean.

Contaminated hot wire or
suction of air may be suspected.

Ground OPEN • It will be over-rich.

Power OPEN • It will be in fail-safe condition,

supply and vehicle runs at an engine
speed from 800 rpm to 1,600
rpm.
Intake air temperature OPEN/
sensor SHORT

Engine coolant temperature OPEN/ • will be in fail-safe condition, and

sensor SHORT then Engine Warning light turns
ON. This malfunction tends to
occur when engine is cold or
when the engine coolant
temperature is high.
Resistance • The engine coolant temperature
is large. is judged as low. This
malfunction tends to occur after
warming up.
Resistance • The engine coolant temperature
is small. is judged as high. This
malfunction tends to occur when
engine is cold.
Heated oxygen sensor OPEN/ • It will be base air-fuel ratio.
SHORT

EC-26
 TROUBLE DIAGNOSIS

Diagnosis Chart by Symptom (Cont’d)

Poor starting

Check that symptoms are detected with self-diagnosis.

Impossible
to start
Engine

Other
Symptoms Poor idle Poor driving control

Check that symptoms are in fail-safe condition.

stall

During surge and constant speed driving

Engine rpm does not increase smoothly.
Inconsistent idle when engine is cold.

Engine over temperature (Overheat)

Inconsistent idle when warming up

Poor fuel consumption efficiency

During surge and acceleration
When engine is warming up
Description/notable

Fast idle is not effective

No initial combustion

characteristics of the
When engine is cold

During a heavy load

During deceleration
Poor power output
Initial combustion

Poor acceleration
symptom

High idle rpm

Low idle rpm

After-burn
Knocking
Backfire

Driving
At Idle
Sensor malfunction
: Highly possible
: Possible

Vehicle speed sensor OPEN/ • Duration of fuel cut becomes

SHORT shorter or fuel may not be cut.
Throttle position sensor OPEN/ • Idle will be base rpm. No
SHORT addition for acceleration.
Output • Possible interruption by
fluctuation unnecessary fuel injection. Poor
ground or control unit
connection may be the cause.

Poor • Idling is judged as OFF during

adjustment idle. Turning ignition switch
repeatedly to ON and OFF will
set the system to normal.

Accelerator pedal position OPEN/

sensor SHORT
Output
fluctuation

Ignition switch IGN OPEN • Impossible to start without

outputs for fuel and ignition
systems.

Neutral SW OPEN • Neutral switch is judged as

OFF, and the target cold engine
speed in N/P position is
lowered.

SHORT • Neutral switch is judged as ON,

and fast idle is effective for cold
engine in positions other than N/
P position, making the creep
larger.
Stop light switch OPEN/
SHORT

Headlight (electrical load) OPEN/

switch SHORT
CAN communication line OPEN/
SHORT

Power supply for ECM OPEN • Impossible to start without

outputs for fuel and ignition
systems.

Sensor ground (coolant OPEN/ • The same as the open circuit in

temperature sensor, throttle SHORT the applicable sensor.
position sensor)

Control unit and connector Poor • A slightly raised connector often

connection, results in poor connection. Entry
water entry? of water causes engine stall,
and afterwards it is momentarily
impossible to restart engine. In
some cases, restarting is
possible after a short wait.
LPG fuel pressure sensor OPEN/
SHORT

Fuel changing switch OPEN • Fuel changing cannot be done.

LPG fuel pressure sensor OPEN • LPG interception valve OFF.

EC-27
 TROUBLE DIAGNOSIS

Diagnosis Chart by Symptom (Cont’d)

RELATIONSHIPS BETWEEN MALFUNCTIONING SYMPTOMS
AND ACTUATOR CIRCUITS
The table below shows the possible symptoms caused by the
malfunction of each actuator circuit.

Poor starting

Check that symptoms are detected with self-diagnosis.

Impossible
to start
Engine

Other
Symptoms Poor idle Poor driving

Check that symptoms are in fail-safe condition.

stall

During surge and constant speed driving

Engine rpm does not increase smoothly.
Inconsistent idle when engine is cold.

Engine over temperature (Overheat)

Inconsistent idle when warming up

Poor fuel consumption efficiency

During surge and acceleration
When engine is warming up

Description/notable
Fast idle is not effective
No initial combustion

characteristics of the
When engine is cold

During a heavy load

During deceleration
Poor power output
Initial combustion

Poor acceleration
symptom
High idle rpm
Low idle rpm

After-burn
Knocking
Backfire

Driving
At Idle
Actuator malfunction
: Highly possible
: Possible

Gasoline injector Power OPEN • No fuel injection to cylinder with

supply open circuit, resulting in LEAN
circuit Momentarily output of heated oxygen
open sensors.
• Starting engine is impossible
Coil OPEN when the circuits for all the
cylinders are open.
Momentarily
open

Drive OPEN
circuit
(ECM Momentarily
side) open

SHORT • Continuous fuel injection to

cylinder with short circuit,
resulting in OVER-RICH and
misfiring.
• Starting engine is impossible
when the circuits for all the
cylinders are open.
Nozzle Foreign • The cylinder with foreign
hole material material will keep injecting.
intrusion
Clogging • The symptom depends on
clogging status. The correction
factor of air-fuel ratio becomes
larger.
Ground OPEN • Shocks may be sensed and
circuit engine stall may be occur
(ECM) depending on the duration of the
operation conditions.
Momentarily
open
Ignition signal circuit OPEN • Slight shocks and surges may
be sensed depending on the
Momentarily duration of momentarily open
open circuit and the operating
conditions.
Ignition coil Power OPEN •
supply
circuit Momentarily • Engine stall may occur if
open duration of momentarily open
circuit is too long.

Coil OPEN • Shocks may be sensed and

engine stall may be occur
depending on the duration of the
operation conditions.

Ground OPEN • Injects fuel toward spark plug on

circuit the cylinder with open circuit.
Momentarily
open

EC-28
 TROUBLE DIAGNOSIS

Diagnosis Chart by Symptom (Cont’d)

Poor starting

Check that symptoms are detected with self-diagnosis.

Impossible
to start
Engine

Other
Symptoms Poor idle Poor driving

Check that symptoms are in fail-safe condition.

stall

During surge and constant speed driving

Engine rpm does not increase smoothly.
Inconsistent idle when engine is cold.

Engine over temperature (Overheat)

Inconsistent idle when warming up

Poor fuel consumption efficiency

During surge and acceleration
When engine is warming up
Description/notable

Fast idle is not effective

No initial combustion

characteristics of the
When engine is cold

During a heavy load

During deceleration
Poor power output
Initial combustion

Poor acceleration
symptom

High idle rpm

Low idle rpm

After-burn
Knocking
Backfire

Driving
At Idle
Actuator malfunction
: Highly possible
: Possible

ECM relay circuit OPEN

Throttle control motor circuit OPEN/

SHORT
Throttle motor relay circuit OPEN • The same malfunction may
occur as power supply open of
throttle control motor and
throttle position sensor.
Heated oxygen sensor OPEN
heater circuit
• Fuel pump relay circuit OPEN • Impossible to start
• Fuel pump circuit
• Ignition relay circuit Momentarily • Impossible to start
open
Fuel pump OPEN/
Pressure regulator SHORT

LPG injector HI side OPEN • LPG interception valve OFF

circuit
SHORT • LPG interception valve OFF

Coil OPEN • LPG interception valve OFF

LO side OPEN • LPG interception valve OFF

circuit
SHORT • LPG interception valve OFF

LPG assistance injector OPEN

Control unit
side short
LPG interception valve relay OPEN

Control unit
side short
LPG interception valve OPEN

Malfunction indicator light OPEN

Improper TAS learning OPEN

EC-29
 TROUBLE DIAGNOSIS

Diagnosis Chart by Symptom (Cont’d)

RELATIONSHIP BETWEEN MALFUNCTIONING SYMPTOM AND
THE ENGINE MAIN BODY/AUXILIARY COMPONENT
The table below shows the possible symptoms caused by the
malfunction of engine main body system. It will be helpful in
malfunction trouble diagnosis. (The table lists general symptoms
and some may not be applicable.)

Poor starting
Impossible

Engine
to start

Other
Symptoms Poor idle Poor driving
stall

During surge and constant speed driving

Engine rpm does not increase smoothly.
Inconsistent idle when engine is cold.

Engine over temperature (Overheat)

Inconsistent idle when warming up

Poor fuel consumption efficiency

During surge and acceleration
When engine is warming up
Fast idle is not effective

Description/notable
No initial combustion

When engine is cold

During a heavy load

During deceleration
Poor power output

characteristics of the symptom

Initial combustion

Poor acceleration
High idle rpm
Low idle rpm

After-burn
Knocking
Backfire

Driving
: Highly possible At Idle
: Possible
: Not very possible
Air sucked from oil level gauge • Air-fuel ratio becomes LEAN.
• High air-fuel correction factor.
Air sucked from oil filler cap • Low suction power (vacuum pressure) of
intake manifold.
Air sucked from PCV hose * Check the suction using a pressure
(downstream of PCV) gauge.
* Generally applicable to air suction in air
Air sucked from intake manifold and intake system
gasket
PCV kept open • Noise (high hissing tone)

Clogged fuel strainer • Symptom depends on clogging status.

This tends to happen during high-speed
Clogged air cleaner element or high load operation.

Malfunctioning gasoline pressure • Symptom varies depending on

regulator combustion pressure.
Fuel mixture

Poor quality gasoline • Symptom varies depending on oil quality.

Improper LPG fuel (cold area and • Starting ability in cold area is changed
propane ratio) depending on propane ratio.
• Use LPG with proper propane ratio.

Malfunctioning LPG vaporizer • If the pressure is low, it is caused by poor

pressure adjusting valve output during high-speed or high load
operation.
• If the pressure is excessively high, relief
valve operates and engine stalls at rich.
Clogged LPG vaporizer hot water • Symptom depends on fuel temperature.
circuit This tends to happen during engine stall
and is impossible to restart during engine
warming up.
Clogged LPG interception valve • Symptom depends on clogging status.
filter This tends to happen during high-speed
or high load operation.

Valve deposit • Air-fuel ratio becomes LEAN. High air-

fuel correction factor.
Improper connection of wire • Check that wiring route is proper.
connector
Poor connection of wire connector • Check that connector is slightly raised.
Poor starting if slightly raised connectors
are in all cylinders.
Sparking

Improper ignition timing adjustment —

Malfunctioning spark plug • Check that the gap is proper. Check

spark plug for electric wear, soil (fuel
injection, smoking), and damaged
insulator.

Leakage from high-pressure parts • Symptom varies depending on the level

of leakage.

EC-30
 TROUBLE DIAGNOSIS

Diagnosis Chart by Symptom (Cont’d)

Poor starting
Impossible
to start
Engine

Other
Symptoms Poor idle Poor driving
stall

During surge and constant speed driving

Engine rpm does not increase smoothly.
Inconsistent idle when engine is cold.

Engine over temperature (Overheat)

Inconsistent idle when warming up

Poor fuel consumption efficiency

During surge and acceleration
When engine is warming up
Fast idle is not effective
Description/notable
No initial combustion

When engine is cold

During a heavy load

During deceleration
Poor power output
characteristics of the symptom
Initial combustion

Poor acceleration
High idle rpm
Low idle rpm

After-burn
Knocking
Backfire

Driving
At Idle
: Highly possible
: Possible
: Not very possible
Improper bulb contact • Symptom varies depending on contact
Compression

condition and the number of cylinders.

pressure

Worn piston ring • Symptom varies depending on degree of

wear and the number of cylinders.

Clogged three-way catalytic • In some cases, after engine stall,

converter /exhaust system restarting is possible.
Low idle base speed • Engine stall may occur by power steering
load and cargo load during deceleration
or at idling.
Dragging of brakes • Tires/wheels are hot.

Belt tension too high (excessive —

tension)
High A/T load • Insufficient ATF amount, improper oil
Other

specification (This symptom may

especially occur in the cold.)
High HYD PUMP load (PS, Cargo) • Malfunctioning oil pressure relief valve,
improper oil specification (This symptom
may especially occur in the cold.)

Foreign material in fuel tank (such • With low fuel, this may easily occur.
as dust)

Damaged fan, malfunctioning water • Noise

pump
Clogged/restricted radiator/ —
condenser

Also check the following items other than the above:

• Check harness tension.
• Check each connector connection.
• Check ground wire for looseness.
• Check battery connection for looseness or corrosion.
• Check water and oil condition.
• Check fan belts for looseness.

EC-31
 TROUBLE DIAGNOSIS

Description
• “When” a malfunction occurs that is caused by the sensors of
engine or the air-fuel ratio control, “{ }” of the meter panel
illuminates. Then, Diagnostic Trouble Code (DTC) is displayed
on the meter. At this time, the possible cause is displayed by
operating the button.
• For DTC, refer to Table of DTC (EC-33).
• When a malfunction has occurred, check the symptom and
perform the trouble diagnosis using “Diagnosis history”, “ECM
input/output monitor” and “Active test” in the meter.
NOTE:
• For “Diagnosis history”, refer to EC-33.
• For “ECM Input/Output Monitor”, refer to EC-44.
• For “ECM Active Test”, refer to EC-45.
• For “Screen flow”, refer to EC-42.

OBD-II Plug to connect generic scan tool (GST).

Fail-Safe Function
When any of the critical sensors or systems sends a malfunction
message, the fail-safe function estimates the driving conditions with
other input signals and selects safer conditions for engine (vehicle)
control, based on data previously stored in ECM.
Engine
Related sensors Malfunction condition Fail-safe Warning
light

Mass air flow sensor Same as self-diagnosis • Selects fuel injection pulse width depending on engine speed and ON
malfunction detection throttle position so the vehicle can be driven. However, fuel injection
conditions. will be inhibited (fuel cut off) when engine speed exceeds
approximately 800 - 1,600 rpm.
• Idle speed is 800 rpm.
Engine coolant • Uses the estimated engine coolant temperature (varies with elapsed ON
temperature sensor time after start) to perform controls so the vehicle can be driven.
Accelerator pedal position • Fuel injection will be inhibited when 1 circuit is opened. Release ON
sensor valve mechanically until it can drive at low speed when disconnecting
connector.
Throttle position sensor • Fixes output to a preset value so the vehicle can be driven. However, ON
fuel injection will be inhibited (fuel cut off) when engine speed
exceeds approximately 2,500 rpm.

EC-32
 TROUBLE DIAGNOSIS

Table of Diagnosis Trouble Code (DTC)

SELF-DIAGNOSIS RESULTS
When a malfunction occurs in ECM input/output signal circuit, the
malfunctioning circuit is recorded and displayed. Also, the
malfunction item that is occurred is displayed.
Display sample [Example: When there is a malfunction in mass air
flow sensor] Display DTC and the malfunction item in the alarm
monitor screen.

DTC Display screen Name Engine warning light

— — NO DTC —
E-03 VCM communication signal
circuit malfunction
—

E-04 ECM communication signal

circuit malfunction
—

E-05 DCM communication signal

circuit malfunction
—

E-07 MP communication signal

circuit malfunction
—

Mass air flow sensor signal

circuit malfunction
E-21 ON

Engine coolant temperature

signal circuit malfunction
E-22 ON

Conditions to turn off Engine Warning light

• The Engine Warning light, marked with *, is turned off when
ignition switch is turned ON (engine starts) again after normal
state is resumed.
• For other self-diagnostic items, self-diagnostic results shall be
erased by turning ignition switch to OFF after normal operation
is resumed.

EC-33
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC for
Malfunction return condition Diagnosis outline Trip
GST
— — — —
U1001 • Malfunction occurs in CAN communication transmit/receive data or in — 2
VCM, and data transmission/reception cannot be confirmed.
• CAN communication data is transmitted/received for predetermined
period.
U1001 • Malfunction occurs in CAN communication transmit/receive data or in — 2
ECM, and data transmission/reception cannot be confirmed.
• CAN communication data is transmitted/received for predetermined
period.
U1001 • Malfunction occurs in CAN communication transmit/receive data or in — 2
DCM, and data transmission/reception cannot be confirmed.
• CAN communication data is transmitted/received for predetermined
period.
U1001 • Malfunction occurs in CAN communication transmit/receive data or in — 2
MP, and data transmission/reception cannot be confirmed.
• CAN communication data is transmitted/received for predetermined
period.
P0102 When the engine is running and the mass air flow sensor output voltage Detect disconnection and short circuit and 1
has been 0.5V or less (open or shorted) for a predetermined period. make MIL go on.
P0103 When the engine is stopped (ignition switch ON) and the mass air flow
sensor output voltage has been approx. 4.9V or more (open or shorted)
for a predetermined period.

P0117 Engine coolant temp. sensor output voltage has been less than 0.06V Detect disconnection and short circuit and 1
(open or shorted) for a predetermined period. make MIL go on.
P0118 Engine coolant temp. sensor output voltage has been approx. 4.8V or
more (open or shorted) for a predetermined period.

Trip 1: If a malfunction is detected by self-diagnosis between

the time ignition switch is turned ON (engine is running) and
then turned OFF (this is defined as “trip”), Engine Warning
light is lit. The corresponding DTC is recorded immediately
after detection.
Trip 2: When a malfunction is detected by self-diagnosis for
the first time in the first trip, a tentative DTC is recorded. If
the same malfunction is detected again by self-diagnosis in
the next trip (second trip), Engine Warning light is lit and the
corresponding final DTC is recorded.

Self-diagnostic results timing

•For items of trip 1, timing “0” is displayed immediately after
detection of a malfunction.
•For items of trip 2, when a malfunction is detected for the
first time (trip 1), timing “1t” is displayed. When a malfunction
is detected again in the next trip (trip 2), it is displayed as “0”.
Accumulative counting is performed at the end of warming-
up operation,

EC-34
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC Display screen Name Engine warning light

Throttle position sensor signal

circuit malfunction

E-23 ON*

Accelerator pedal position

sensor signal circuit
malfunction

E-24 —

Heated oxygen sensor signal

E-25 circuit malfunction —

Heated oxygen sensor heater

signal malfunction
E-26 —

Conditions to turn off Engine Warning light

• The Engine Warning light, marked with *, is turned off when
ignition switch is turned ON (engine starts) again after normal
state is resumed.
• For other self-diagnostic items, self-diagnostic results shall be
erased by turning ignition switch to OFF after normal operation
is resumed.

EC-35
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC for
Malfunction return condition Diagnosis outline Trip
GST
P0122 Throttle position sensor 2 output voltage has been approx. 0.3V or less Detect disconnection and short circuit and 1
(open) for a predetermined period. make MIL go on.
P0123 Throttle position sensor 2 output voltage has been approx. 4.8V or more
(shorted) for a predetermined period.
P0222 Throttle position sensor 1 output voltage has been approx. 0.3V or less
(open) for a predetermined period.
P0223 Throttle position sensor 1 output voltage has been approx. 4.8V or more
(shorted) for a predetermined period.
P1225 When the throttle valve closed position learning value is excessively low. Compare inconsistency between two separate
P1226 When the throttle valve closed position learning cannot be performed. circuits which are installed for redundancy and
P2135 A malfunction occurs in the relation between throttle position sensors 1 judges abnormal condition and make MIL go
and 2. on.

P2122 Accelerator pedal position sensor 1 output voltage has been approx. Detect disconnection and short circuit and 1
0.15V or less (open) for a predetermined period. make MIL go on.
P2123 Accelerator pedal position sensor 1 output voltage has been approx. 5V
or more (shorted) for a predetermined period.
P2127 Accelerator pedal position sensor 2 output voltage has been approx.
0.15V or less (open) for a predetermined period.
P2128 Accelerator pedal position sensor 2 output voltage has been approx. 5V
or more (shorted) for a predetermined period.
P2138 A malfunction occurs in the relation between accelerator pedal position Compare inconsistency between two separate
sensors 1 and 2. circuits which are installed for redundancy and
judges abnormal condition and make MIL go
on.
P0132 Heated oxygen sensor output voltage is higher than normal (1.4V or Detect disconnection and short circuit and 2
more). make MIL go on.
P0134 Heated oxygen sensor signal circuit is open.
P0031 Heated oxygen sensor heater control voltage has been approx. less than Detect disconnection and short circuit of an 2
0.12V (open or shorted) for a predetermined period. oxygen sensor heater circuit and make MIL go
P0032 Heated oxygen sensor heater control voltage has been approx. 4.7V or on.
more (shorted) for a predetermined period.

Trip 1: If a malfunction is detected by self-diagnosis between the

time ignition switch is turned ON (engine is running) and then turned
OFF (this is defined as “trip”), Engine Warning light is lit. The
corresponding DTC is recorded immediately after detection.
Trip 2: When a malfunction is detected by self-diagnosis for the first
time in the first trip, a tentative DTC is recorded. If the same
malfunction is detected again by self-diagnosis in the next trip
(second trip), Engine Warning light is lit and the corresponding final
DTC is recorded.

Self-diagnostic results timing

• For items of trip 1, timing “0” is displayed immediately after
detection of a malfunction.
• For items of trip 2, when a malfunction is detected for the first
time (trip 1), timing “1t” is displayed. When a malfunction is
detected again in the next trip (trip 2), it is displayed as “0”.
Accumulative counting is performed at the end of warming-up
operation,

EC-36
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC Display screen Name Engine warning light

Crankshaft position sensor

signal circuit malfunction
E-27 ON

Camshaft position sensor

(PHASE) signal circuit
malfunction
E-28 ON

Self shut off malfunction

E-29 —

ECM circuit malfunction

E-30 ON*

Electric throttle control actuator

control signal circuit
malfunction

E-31 —

Overheat signal (STEP1)

E-32 —

Overheat signal (STEP2)

E-33 ON*

Ignition signal circuit

E-34 malfunction —

Conditions to turn off Engine Warning light

• The Engine Warning light, marked with *, is turned off when
ignition switch is turned ON (engine starts) again after normal
state is resumed.
• For other self-diagnostic items, self-diagnostic results shall be
erased by turning ignition switch to OFF after normal operation
is resumed.

EC-37
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC for Malfunction return condition Diagnosis outline Trip
GST
P0335 • The crankshaft position sensor (POS) signal is not detected for a Detect abnormal crank angle sensor signal and 2
predetermined time at engine start or during engine running (during make MIL go on.
camshaft position sensor (PHASE) signal input).
• A crankshaft position sensor (POS) signal irregular waveform is
detected for a predetermined time during engine running (during
camshaft position sensor (PHASE) signal input).

P0340 • At start-up, no camshaft position sensor (PHASE) signal has been Detect abnormal cam angle sensor signal and make 2
detected for more than a predetermined period. MIL go on.
• The camshaft position sensor (PHASE) signal is not detected for a
predetermined time during engine running (during crankshaft position
sensor (POS) signal input).
• A camshaft position sensor (PHASE) signal irregular waveform is
detected for a predetermined time during engine running (during
crankshaft position sensor (POS) signal input).

P0605 Self shut off of ECM doesn’t operate normally. — 1

P0605 CPU system or circuits in ECM have a malfunction. Detect abnormal condition in CPU or an engine 1 or 2
control module circuit and make MIL go on. (Note)

P1065 Power is not supplied to ECM for some time. Detect insufficient power supply for ECM and make
MIL go on.
P1229 Sensor power supply voltage has been 5.6V or more or less than Detect improper voltage output for sensors and
4.6V for a predetermined period. make MIL go on.
P1124 Electric throttle control motor power supply circuit is shorted. Detect disconnection and short circuit of a motor 1
driving circuit and make MIL go on.
P1126 Electric throttle control motor power supply circuit is open.
P1128 Electric throttle control motor signal circuit is shorted.
P0605 When an abnormal occurs for the target of throttle position. Compare the difference between target throttle Locked
position and actual throttle position, judge abnormal ON: 1
P1121 Because of mechanical malfunction of the electric throttle control condition and make MIL go on. Locked
actuator, the electric throttle control actuator does not operate OFF: 2
normally.
P1122 • When a malfunction occurred due to the correlation between the
target throttle position and the actual throttle position.
• Over current flows into throttle motor control circuit.

P1218 Engine coolant temp. sensor output voltage has been approx. 0.35V — 1
or less for a predetermined period (with the coolant temp. sensor
normal)

P1217 Engine coolant temp. sensor output voltage has been approx. 0.35V Detect overheat condition by water temperature 1
or less for a predetermined period (with the coolant temp. sensor sensor and make MIL go on.
normal)
P0350 Ignition signal has not been continuously generated while the engine Detect electric current in an ignition coil circuit, judge 1
is running. abnormal ignition interval and make MIL go on.

Trip 1: If a malfunction is detected by self-diagnosis between the time

ignition switch is turned ON (engine is running) and then turned OFF
(this is defined as “trip”), Engine Warning light is lit. The
corresponding DTC is recorded immediately after detection.
Trip 2: When a malfunction is detected by self-diagnosis for the first time
in the first trip, a tentative DTC is recorded. If the same malfunction is
detected again by self-diagnosis in the next trip (second trip), Engine
Warning light is lit and the corresponding final DTC is recorded.

Self-diagnostic results timing

• For items of trip 1, timing “0” is displayed immediately after
detection of a malfunction.
• For items of trip 2, when a malfunction is detected for the first time
(trip 1), timing “1t” is displayed. When a malfunction is detected
again in the next trip (trip 2), it is displayed as “0”. Accumulative
counting is performed at the end of warming-up operation,

EC-38
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC Display screen Name Engine warning light

LPG fuel injection open circuit

E-35 malfunction —

LPG vaporizer malfunction

E-38 —

Oil pressure sensor malfunction

E-40 —

Stop light switch malfunction

E-41 —

GAS air-fuel ratio malfunction

E-42 ON*

LPG air-fuel ratio malfunction

E-43 ON*

LPG fuel pressure sensor

E-36 malfunction ON*

Conditions to turn off Engine Warning light

• The Engine Warning light, marked with *, is turned off when
ignition switch is turned ON (engine starts) again after normal
state is resumed.
• For other self-diagnostic items, self-diagnostic results shall be
erased by turning ignition switch to OFF after normal operation
is resumed.

EC-39
 TROUBLE DIAGNOSIS

Table of DTC (Cont’d)

DTC for
Malfunction return condition Diagnosis outline Trip
GST
P1240 Over current flows into LPG injector 1 (injection area). Detect abnormal electric current in an LPG 1
P1241 Over current flows into LPG injector 1 (no injection area). injector driving circuit and make MIL go on.
P1249 • LPG fuel pressure sensor circuit is open. Detect abnormally higher fuel pressure by 1
• LPG fuel pressure in fuel piping from LPG Vapo to injector has been LPG fuel pressure sensor and make MIL go
excessively increased for a predetermined period. on.
— — — —

P1805 Brake switch signal circuit is open or shorted. — 1

P1814 After engine warmed with gasoline fuel, when oxygen sensor signal is Air-fuel ratio does not cross stoichiometry for 1
stuck and does not reverse at a condition of A/F ratio is excessively lean a long time during intended closed-loop
or rich. operation. (written in 40CFR Parts 1048.110.)
P1148 After engine is started with gasoline fuel, when closed-loop control does
not start within a predetermined period.
P1815 After engine warmed with LPG fuel, when oxygen sensor signal is stuck Air-fuel ratio does not cross stoichiometry for 1
and does not reverse at a condition of A/F ratio is excessively lean or rich. a long time during intended closed-loop
P1817 After engine is started with LPG fuel, when closed-loop control does not operation. (written in 40CFR Parts 1048.110.)
start within a predetermined period.
P1245 LPG fuel pressure sensor circuit is shorted. Detect disconnection and short circuit and 1
make MIL go on.

Trip 1: If a malfunction is detected by self-diagnosis between the

time ignition switch is turned ON (engine is running) and then turned
OFF (this is defined as “trip”), Engine Warning light is lit. The
corresponding DTC is recorded immediately after detection.
Trip 2: When a malfunction is detected by self-diagnosis for the first
time in the first trip, a tentative DTC is recorded. If the same
malfunction is detected again by self-diagnosis in the next trip
(second trip), Engine Warning light is lit and the corresponding final
DTC is recorded.

Self-diagnostic results timing

• For items of trip 1, timing “0” is displayed immediately after
detection of a malfunction.
• For items of trip 2, when a malfunction is detected for the first
time (trip 1), timing “1t” is displayed. When a malfunction is
detected again in the next trip (trip 2), it is displayed as “0”.
Accumulative counting is performed at the end of warming-up
operation,

EC-40
TROUBLE DIAGNOSIS

Service Tool
OBD SYSTEM COUNTER (FOR TRIP 2 DETECTION DIAGNOSIS
WHEN MIL TURNS ON)
Relation of MIL, first trip DTC, DTC and possible detection
items
• When the malfunction is detected for the first time, ECM records
first trip DTC.
• When the same malfunction is detected twice continuously,
ECM records DTC and MIL turns ON.
• MIL turns OFF after driving the vehicle by 3 trips without the
malfunction. If the same malfunction occurs while counting, the
counter is reset.
• DTC is displayed until the vehicle is driven by 40 trips while the
same malfunction is not reproduced.
• If the self-diagnosis result is OK at the second trip, the first trip
DTC is not displayed.

TABLE OF COUNTER SYSTEMS

Unit: Trip

Items Trips Driving conditions

MIL (OFF) 3 B
DTC (CLEAR) 40 A
First trip DTC (CLEAR) 1 B

Driving conditions
• Driving condition A
Driving condition A is the condition that the engine can be warmed
up.
Specifically, count up the counter if all of the following conditions are
satisfied.
• The engine speed becomes 400 rpm or more.
• The engine coolant temperature rises 20 C (68 F) or more after
the engine is started.
• The engine coolant temperature becomes 70 C (158 F) or
more.
• The ignition switch turns OFF from ON.
NOTE:
• When the same malfunction is detected regardless of the driv-
ing condition, the A counter is reset.
• Count up the A counter when the above conditions are satisfied
while the same malfunction not detected.
• When the A counter reaches 40, DTC is not displayed.
• When the A counter counts once while the same malfunction is
not detected after ECM records first trip DTC, first trip DTC is
cleared.

EC-41
TROUBLE DIAGNOSIS

Service Tool (Cont’d)

• Driving condition B
Driving condition B is the condition that all diagnosis can be
performed just once.
Specifically, count up the counter if all of the following conditions are
satisfied.
• The engine speed becomes 400 rpm or more.
• The engine coolant temperature becomes 70 C (158 F) or
more.
• The vehicle speed of 6 - 40 km/h (4 - 25 MPH) continues for 3
seconds or more at closed loop control.
• The vehicle speed of 4 km/h (2 MPH) or less and the idle
determination ON continue for 5 seconds or more at closed loop
control.
• Allow 6 minutes or more to pass after starting the engine.
NOTE:
• When the same malfunction is detected regardless of the driv-
ing condition, the B counter is reset.
• Count up the B counter when the above conditions are satisfied
while the same malfunction is not detected.
When the B counter reaches 3 without the malfunctions, MIL
turns OFF.

• Data monitor
• Allows determination and identification of the possible source of
a malfunction based on self-diagnosis test results.
• Displays ECM input/output signal data in real time.
• Records the data before and after engine stalls, falters or
refuses to start intentionally.

EC-42
TROUBLE DIAGNOSIS

Self-Diagnosis Function (Without Service

tool)

DIAGNOSTIC TEST MODE II - SELF-DIAGNOSTIC RESULTS

• In this mode, the MIL blinks (indicating the DTC) to identify the
system that returned a malfunction.
• If no DTC is detected, DTC "0000" is displayed.

EC-43
 TROUBLE DIAGNOSIS

ECM Input/Output Monitor Reference Data

In ECM input/output monitor, the items related to engine control
(engine status, sensors or switches) can be checked.
Items Display screen Name Remarks (Display, etc.)

A2-01 (Upper) Engine speed Idle speed: 700 rpm, maximum engine speed without
load: 2,800 rpm
A2-01 (Lower) Closed throttle position switch Accelerator fully-closed: ON, accelerator open: OFF
A2-02 (Upper) Throttle opening angle At idle: 0%, accelerator fully-open: 100%
A2-02 (Lower) Battery voltage
A2-03 (Upper) Accelerator pedal position At idle: 0%, accelerator fully-open: 100%
A2-03 (Lower) Engine coolant temperature Approx. 80 C (176 F) or more after warming up engine
A2-04 (Upper) Injection pulse GAS At idle: 2-4 s
A2-04 (Lower) Injection pulse LPG At approx. 2,000 rpm: Approx. 2 - 4 s
A2-05 (Upper) Starter switch Ignition switch ON and START: ON, ignition switch OFF:
OFF
A2-05 (Lower) Neutral switch FR lever in neutral: ON, any position other than neutral:
OFF
A2-06 (Upper) Electricity load switch Headlight switch ON: ON, OFF: OFF
A2-06 (Lower) Brake switch Depressing brake pedal: ON, Not depressing brake
pedal: OFF
A2-07 (Upper) Air conditioner switch Not specified
A2-07 (Lower) Learned Air-fuel ratio value clear DONE/NOT
A2-08 (Upper) Idle Air Volume Learning (Factory) Not used
A2-08 (Lower) Idle Air Volume Learning (Normal) EXE/NOT
A2-09 (Upper) Ignition timing adjustment EXE/NOT
A2-09 (Lower) Air-fuel ratio adjustment EXE/NOT
A2-10 (Upper) Power balance adjustment EXE/NOT
A2-10 (Lower) Fuel pressure clear adjustment EXE/NOT
A2-11 (Upper) Self-diagnosis result clear DONE/NOT
A2-11 (Lower) Mass air flow sensor At idle: Approx. 1.3V, engine speed at 2,000 rpm:
Approx. 1.6V
A2-12 (Upper) Charging efficiency GAS At idle: Approx. 30%, At approx. 2,000 rpm: Approx.
20%
A2-12 (Lower) Charging efficiency LPG At idle: Approx. 30%, At approx. 2,000 rpm: Approx.
20%
A2-13 (Upper) Air-fuel ratio (Gasoline) Proper value: 100%, range: 75 - 125%
A2-13 (Lower) Air-fuel ratio (LPG) Proper value: 100%, range: 75 - 125%
A2-14 (Upper) Change fuel switch 1 LPG: ON, GAS: OFF
A2-14 (Lower) Change fuel switch 2 GAS: ON, LPG: OFF
A2-15 (Upper) Fuel control GAS/LPG/NEU
A2-15 (Lower) Mast high switch 1 Not specified
A2-16 (Upper) Mast high switch 2 Not specified
A2-16 (Lower) O2 sensor RICH/LEAN judgement While the engine is running: Switches between LEAN/
RICH
A2-17 (Upper) Fuel pump relay Ignition switch ON (when the fuel pump is operating),
OFF (when the fuel pump is stopped)
A2-17 (Lower) LPG interception valve relay When the engine is stopped: OFF, while the engine is
running: ON
A2-18 (Upper) Throttle relay Ignition switch ON: ON, OFF: OFF
A2-18 (Lower) Heated oxygen sensor heater At idle after warning up the engine: ON
A2-19 (Upper) Fully-closed learning update DONE/NOT
empirical flag
A2-19 (Lower) Idle Air Volume Learning (Factory/ DONE/NOT
Normal) completion flag
A2-20 (Upper) CONSULT-II connecting flag ON/OFF
A2-20 (Lower) Ignition timing Proper value: 0 (at idle), range: 0 - 10
NOTE: When the display is “99”, it means a minus.

EC-44
 TROUBLE DIAGNOSIS

ECM Input/Output Monitor Reference Data

(Cont’d)
Items Display screen Name Remarks (Display, etc.)

A2-21 (Upper) Heated oxygen sensor output At idle: Changes between approx. 0.1 - 0.4V 0.6 - 0.9V
voltage Maintain at approx. 2,000 rpm: Changes between
approx. 0.1 - 0.4V 0.6 - 0.9V
A2-21 (Lower) Intake air temperature sensor Values according to intake air temperature
A2-22 (Upper) LPG fuel pressure sensor Ignition switch ON: Approx. 29 kPa (0.29 bar, 0.3 kg/
cm2, 4 psi)

ECM Active Test

ECM active test has the following items.
Items Display screen Name Reference page

D2-01 (Upper) Idle Air Volume (Normal) EC-46

D2-01 (Lower) Air-fuel ratio adjustment EC-48
D2-02 (Upper) Air-fuel ratio clear EC-48
D2-02 (Lower) Ignition timing adjustment EC-50
D2-03 (Upper) Fuel pressure clear EC-50
D2-03 (Lower) Power balance EC-52
D2-04 (Upper) Self-diagnosis clear EC-52
D2-04 (Lower)

(1) Idle Air Volume Learning

If the idle speed or the ignition timing is outside the standard (engine
status is malfunctioning) or if the electronic throttle control actuator
or ECM is replaced, perform Idle Air Volume Learning.

Standard
Idle speed: 700 50 rpm
Ignition timing: 0 2/700 ( BTDC/rpm)

(2) Air-fuel ratio adjustment

If the values of “Air-fuel ratio” in ECM input/output monitor are
outside the standard, adjust the air-fuel ratio.

Proper value: 100%

Adjustment range: 75 - 125%

(3) Ignition timing adjustment

If the values of “Ignition timing” in ECM input/output monitor are
outside the standard, adjust the ignition timing.

Proper value: 0
Adjustment range: 0 - 10

(4) Fuel pressure clear

Relieve fuel pressure before removing fuel piping to secure safety.
For relieving procedure of fuel pressure, refer to “Fuel pressure
clear”.

(5) Power balance

When the engine does not run smoothly or the misfires occur in
some cylinders, forcibly stop each cylinder in “Power balance”, and
then check which cylinder has the malfunction.

EC-45
TROUBLE DIAGNOSIS

Idle Air Volume Learning:

Perform (Cancel) Idle Air Volume Learning
(Normal).

EC-46
TROUBLE DIAGNOSIS

Air-fuel Ratio Adjustment:

Change the adjustment value from 85 dec to
100 dec, and then adjust air-fuel ratio.

PRECAUTIONS FOR ECM ACTIVE TEST

Air-fuel ratio adjustment
For performing the test of air-fuel ratio adjustment, please refer to
the following table.

Test item Proper value Adjustment range

Air-fuel ratio adjustment 100 75 - 125

Air-fuel ratio adjustment:

First, the current adjustment value is displayed. Set the adjustment
value to “100” (Proper value), and then perform the adjustment
once. Check the adjustment value again. Confirm that the
adjustment value is changed to “100”. If the adjustment value does
not change, set the adjustment value to “100” and perform the
adjustment. Reference: Whether the air-fuel ratio is adjusted or not
can be checked by performing the adjustment with the adjustment
value between 75 and 125 since second times. (Please note that the
proper test may not be performed when performing the adjustment
without the adjustment range “75 - 125”.)

EC-47
TROUBLE DIAGNOSIS

Learned Air-fuel Ratio Value:

Clear (Cancel) learned air-fuel ratio value.

EC-48
TROUBLE DIAGNOSIS

Ignition Timing Adjustment:

Change the adjustment value from 5 dec to 0
dec, and then adjust ignition timing.

PRECAUTIONS FOR ECM ACTIVE TEST

Ignition timing adjustment
For performing the test of ignition timing adjustment, please refer to
the following table.

Test item Proper value Adjustment range

Ignition timing adjustment 0 0 - 10

Ignition timing adjustment:

First, the current ignition timing is displayed. Set the adjustment
value to “0” (Proper value), and then perform the adjustment once.
Whether the ignition timing is adjusted or not can be checked by
performing the adjustment with the adjustment value between 0 and
10 since second times. (Please note that the proper test may not be
performed when performing the adjustment without the adjustment
range “0 - 10”.)
When the ignition timing is a minus, “99” is displayed.

EC-49
TROUBLE DIAGNOSIS

Fuel Pressure Clear:

Perform (Cancel) fuel pressure clear.

EC-50
TROUBLE DIAGNOSIS

Power Balance:
Stop No. 3 cylinder in power balance.

CAUTION:
LPG model does not have the power balance function. Do not
perform this adjustment.
If it is performed, the screen will stop. Please cancel the
function by turning the ignition key OFF.
The engine cylinder status is shown by O or X as in the above figure.
These symbols mean No. 1 cylinder, No. 2 cylinder, No. 3 cylinder,
No. 4 cylinder, No. 5 cylinder and No. 6 cylinder from the left. (*
Since this vehicle has only 4 cylinders, No. 5 cylinder and No. 6
cylinder are not used for ACTIVE TEST even though these are
displayed.)
The cylinder stops by changing the set values of each cylinder from
O to X and performing the adjustment.

EC-51
TROUBLE DIAGNOSIS

Self-diagnosis Clear:
Perform (Cancel) self-diagnosis.

EC-52
 BASIC INSPECTION

BASIC INSPECTION Inspection of Idle Speed and Ignition Timing

SERVICE DATA AND SPECIFICATIONS (SDS)
Fuel pressure gasoline [(kPa, bar, kg/cm2, psi)] 51 psi At idle: 353 kPa (3.53 bar, 3.6 kg/cm2 , 51 psi)
Idle speed (rpm) A/T model (at N position) 700±50
Ignition timing (°BTDC/rpm) A/T model (at N position) 0±2/700
Firing order 1-3-4-2
Spark plug Manufacturer/type/gap mm (in) NGK/FR2A-D/0.8 - 0.9 (0.0031 - 0.035)
Ignition advance device Electrically controlled ignition advance
Density of CO at idle speed (%)/Density of HC at idle speed (ppm) 0.1/50 or less

• Turn ignition switch ON, and then make sure that no

malfunction is detected by self-diagnosis.
• Make sure that engine is free of oil pressure pump loads and
any electrical loads. Perform the inspection with the shift lever in
the neutral or N position.
• Warm up engine and transmission to the normal operating
temperature.

IDLE SPEED
With ECM Input/Output monitor

NOTE:
The idle speed can be checked in ECM Input/Output Monitor. (Refer
to EC-44.)

CAUTION:
Perform “Idle Air Volume Learning” (on page EC-46) when idle
speed is outside the standard.
Without ECM Input/Output monitor
1. Connect an induction type (current detection type) tachometer
to the primary wire of the 1 cylinder to check idle speed.
• The primary wire for the 1 cylinder is looped and longer than the
wires for other cylinders. It is used for detecting idle speed and
ignition timing.
2. Make sure that idle speed is 700 50 rpm.

CAUTION:
Perform “Idle Air Volume Learning” (on page EC-46) when idle
speed is outside the standard.
IGNITION TIMING INSPECTION
NOTE:
The ignition timing can be checked in ECM Input/Output monitor.
(Refer to EC-44.)
1. Install a timing light to the primary wire for 1 cylinder.
2. Make sure that ignition timing and idle speed are 0 2°BTDC/
700 rpm.

CAUTION:
Perform “Idle Air Volume Learning” (on page EC-46) when
ignition timing is outside the standard.

EC-53
BASIC INSPECTION

Throttle Valve Closed Position Learning and

Idle Air Volume Learning
DESCRIPTION
When electric throttle control actuator or ECM connector is removed,
it is necessary for ECM to learn throttle valve closed position (throttle
position sensor output with throttle valve fully closed) after
reinstallation. Thus, throttle valve closed position learning is
performed.
When electric throttle control actuator or ECM is replaced, the
minimum required idle air volume needs to be learned. Thus, throttle
valve closed position learning and idle air volume learning are
performed.
Idle air volume learning is necessary even when idle speed or
ignition timing is outside the standard. Note that idle air volume
learning is equivalent to the base idle speed adjustment by
conventional throttle adjusting screw of carburetor or LPG mixer.

OPERATION PROCEDURE FOR THROTTLE VALVE CLOSED

POSITION LEARNING
1. Turn ignition switch ON OFF. (And hold it for approximately 5
seconds after turning it OFF.)
2. Make sure that throttle valve operates. (Check for operating
sound.)
3. Upon completion of the above, learning is complete.

CAUTION:
Throttle valve closed position learning cannot be performed
with Service tool.
OPERATION PROCEDURE FOR IDLE AIR VOLUME LEARNING
1. Perform throttle valve closed position learning.
2. Fully warm up engine, transmission, and lubricant. [Engine
coolant temperature: 70 to 90°C (158 to 194°F)]
3. Set the selector lever to neutral or N position. Make sure that
the engine is free of electrical loads, such as air conditioner, oil
pressure pump, and other electrical components.
4. Perform “Idle Air Volume Learning” of “ECM Active Test”. (Refer
to EC-45.)

CAUTION:
“IDLE AIR VOL LEARN (PLANT)” is the original setting on the
vehicle. Do not use it.

EC-54
BASIC INSPECTION

Throttle Valve Closed Position Learning and

Idle Air Volume Learning (Cont’d)
CAUTION:
It will take approximately 20 seconds to complete the idle air
volume learning. Do not turn OFF the ignition switch until
completion.
• Complete “Idle Air Volume Learning”, then make sure that idle
speed and ignition timing are within the standard.
• Perform “Idle Air Volume Learning” again if values are outside
the standard.

Accelerator Pedal Released Position

Learning
DESCRIPTION
When the accelerator pedal assembly has been replaced or the accelerator
pedal position sensor connector has been disconnected, the accelerator
pedal released position needs to be learned after being repaired, so learn
accelerator pedal in fully-released position.

OPERATION PROCEDURE
1. Turn ignition switch ON and wait at least 2 seconds.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Then turn ignition switch ON again and wait at least 2 seconds
(learning completed).

Fuel Pressure Inspection

QUICK INSPECTION
With Active Test
1. Perform “Fuel pressure clear” of ECM Active Test. (Refer to EC-
45.)
2. Pinch the fuel feed hose with the fingers. Hose should not feel
hard.
Without Active Test
• When the fuel feed hose is squeezed while fuel pump is
operating (for 1 second after the ignition switch is turned ON or
while cranking), the hose should be swelling with pressure or
pulsating.

FUEL PRESSURE INSPECTION

CAUTION:
• Safely and securely remove and install fuel hose.
• Use the fuel pressure gauge for fuel pressure inspection.
• Do not inspect fuel pressure while other systems are operat-
ing. Malfunctions may occur in fuel pressure value.
1. Release the fuel pressure.
2. Install fuel pressure gauge using fuel hose for fuel pressure
inspection.
3. Remove fuel hose, and then install fuel hose for fuel pressure
inspection.

CAUTION:
Usable period of fuel hose for fuel pressure inspection is 30 times
or less. (Fuel hoses that are damaged and allow fuel leakage are
not contained above.)

EC-55
BASIC INSPECTION

Fuel Pressure Inspection (Cont’d)

4. Turn ignition switch ON, and then make sure that there is no
fuel leakage.
5. Start engine, and check for fuel leakage.
6. Make sure that fuel pressure is within the standard.
At idle: 353 kPa (3.53 bar, 3.6 kg/cm2, 51 psi)

• If the vehicle shows poor starting, check fuel pressure with fuel
pump operating for approximately 1 second after ignition switch
is turned ON, and during cranking.
For 1 second after ignition switch is turned ON and
during cranking: 353 kPa (3.53 bar, 3.6 kg/cm 2, 51
psi)

• Check the following items if a malfunction is detected.

CAUTION:
Also check fuel pressure at increased engine speed.
• Malfunctioning pressure regulator (integrated with fuel pump)
• Clogged fuel piping
• Clogged fuel filter (with fuel pump)
• Poor fuel pump discharge
•

FUEL PRESSURE RELEASE

CAUTION:
Relieve fuel pressure before removing fuel piping to secure
safety.

Accelerator Pedal Released Position

Learning
With Active Test
1. Perform “Fuel pressure clear” of ECM Active Test. (Refer to EC-
45.)
2. Crank engine 2 or 3 times to consume the fuel in the fuel line
after it stalls.
3. Turn ignition switch OFF.

Without Active Test

1. Disconnect fuel pump fuse.
2. Start engine.
3. Crank engine 2 or 3 times to consume the fuel in the fuel line
after it stalls.
4. Turn OFF the ignition switch, and install the fuel pump fuse.

EC-56
 COMPONENT PARTS INSPECTION

COMPONENT PARTS Crankshaft Position Sensor (POS)

Check resistance between terminals using an analog circuit tester.
At room temperature
(+) - (-) Resistance
3-1 : Not 0 nor
2-1 : Not 0 nor
3-2 : Not 0 nor

CAUTION:
Measurement values will vary depending on the measurement
range of circuit tester. Note that the higher the range is, the
ECM0086 larger the resistance is.

Camshaft Position Sensor (PHASE)

Check resistance between terminals using an analog circuit tester.
At room temperature
(+) - (-) Resistance
3-1 : Not 0 nor
2-1 : Not 0 nor
3-2 : Not 0 nor

CAUTION:
Measurement values will vary depending on the measurement
ECM0091 range of circuit tester. Note that the higher the range is, the
larger the resistance is.

Mass Air Flow Sensor

1. Remove mass air flow sensor.
2. Turn ignition switch to ON. While blowing air into the mass air
flow sensor from the air cleaner case side, check output voltage
between terminal 3 and ground.
No air blowing: Approx. 1V
With air blowing: Approx. 1.3V
(The more the air is blown, the higher the voltage is.)

CAUTION:
If air is blown from the air duct side, the voltage becomes
lower.

Engine Coolant Temperature Sensor

Check resistance between terminals 1 and 2 on the engine coolant
temperature sensor.
Resistance
Coolant temperature at approx. 20°C (68°F): Approx.
2.5 k
Coolant temperature at approx. 80°C (176°F): Approx.
0.3 k

EC-57
 COMPONENT PARTS INSPECTION

Engine Coolant Temperature Sensor

(Cont’d)

ECM0383

Throttle Position Sensor 1, 2 (Electric

throttle control actuator assembly)
Check voltage between ECM terminal 50, 69 and ground.
Terminal At idle after At approx.
Signal name
signal warming up 2,000 rpm
50 - (-) Throttle position sensor 1 Approx. 0.6V Approx. 0.7V
69 - (-) Throttle position sensor 2 Approx. 4.5V Approx. 4.4V

CAUTION:
• Make sure that there is no moisture around connector
when removing and installing throttle position sensor con-
ECM0101
nector. If there are any water drops, completely wipe them
off.
• Do not apply voltage to throttle position sensor terminal.
• Perform “Throttle Valve Closed Position Learning” if dis-
connecting connector. Perform “Throttle Valve Closed
Position Learning and Idle Air Volume Learning” if replac-
ing electric throttle control actuator. (Refer to EC-54,
“Throttle Valve Closed Position Learning and Idle Air Vol-
ume Learning”.)
• Do not disassemble electric throttle control actuator.
COMPONENT PARTS INSPECTION Accelerator Pedal Position Sensors 1, 2
(Accelerator work unit)
Check voltage between ECM terminal 106, 98 and ground.
At approx.
Terminal Signal name At Idle
2,000 rpm

106 Accelerator pedal position sensor 1 Approx. 0.67 - Approx. 0.65V

0.87V
98 Accelerator pedal position sensor 2 Approx. 0.335 Approx. 0.35V
- 0.435V

CAUTION:
ECM0103 • Do not apply voltage to accelerator pedal position sensor
terminal.
• Do not disassemble accelerator work unit.

EC-58
COMPONENT PARTS INSPECTION

Intake Air Temperature Sensor (Joined with

mass air flow sensor)
Check resistance between intake air temperature sensor (mass air
flow sensor connector) terminals 3 and 5.
Resistance
Intake air temperature at approx. 20 C (68 F): Approx. 2.5
k
Intake air temperature at approx. 80 C (176 F): Approx. 0.3
k

ECM0384

Stop Light Switch

Check continuity between stop light switch terminals 1 and 2.
Brake pedal released: Continuity should not exist.
Brake pedal depressed: Continuity should exist.

ECM0108

Spark Plug
1. Check electrode for dirt, damage, and wear and insulator for
damage.
2. Replace spark plug if necessary.

CAUTION:
• Check terminals for looseness.
• Check insulator for cracks or damage.
• Check for contamination by oil, water, and dust.
• Make sure that the spark plug gap is normal, using a feeler
gauge.
ECM0117 Spark plug gap: 0.8 - 0.9 mm (0.031 - 0.035 in)

EC-59
COMPONENT PARTS INSPECTION

Ignition Coil
Check the resistance between terminals of the power transistor by
applying and exchanging (+ and -) the inspection rods of an analog
circuit tester.
(+) - (-) Resistance (at room temperature)
1-2 : Not 0 nor
2-1 : Not 0 nor
3-1 : Except 0
1-3 : Except 0
3-2 : Except 0
2-3 : Except 0
ECM0118
CAUTION:
Do not use a digital circuit tester because the standard is
different.

Gasoline Injector
Check resistance between each cylinder injector terminals 1 and 2.
Standard resistance (all cylinders): Approx. 14.5
(at room temperature)

ECM0123

WITH ECM INPUT/OUTPUT MONITOR

1. Check “INJ PULSE GAS” (gasoline) or “INJ PULSE LPG” (LPG)
in Input/Output monitor, and increase the engine speed to
approximately 2,500 rpm after warming up engine.
2. Make sure that “INJ PULSE GAS” (gasoline) or “INJ PULSE
LPG” (LPG) instantly drops when accelerator pedal is released
(Refer to EC-54).

WITHOUT SERVICE TOOL

1. Warm up the engine sufficiently.
2. Disconnect harness connector of the injector and connect a test
light.
3. Release the accelerator pedal at the engine speed of
approximately 2,500 rpm or more, and confirm test light goes off
for a moment.

ECM0147

EC-60
COMPONENT PARTS INSPECTION

Fuel Pump
Check resistance between terminals 3 and 6.
Resistance: Approx. 1 (at room temperature)

Electric Throttle Control Motor (Electric

throttle control actuator assembly)
Check resistance between electric throttle control motor (throttle
position sensor connector) terminals 3 and 6.
Resistance: Approx. 1 -15 [at 25°C (77°F)]

CAUTION:
• Make sure that there is no moisture around connector
when removing and installing throttle position sensor con-
nector. Completely wipe off water drops if there are any.
• Do not apply voltage to electric throttle control motor ter-
minal.
• Perform “Throttle Valve Closed Position Learning” if dis-
connecting connector. Perform “Throttle Valve Closed
Position Learning and Idle Air Volume Learning” if replac-
ing electric throttle control actuator. (Refer to EC-54,
“Throttle Valve Closed Position Learning and Idle Air Vol-
ume Learning”.)
• Do not disassemble electric throttle control actuator.

Heated Oxygen Sensor

Check resistance between heated oxygen sensor terminals 2 and 3.
Resistance: Approx. 3.3 - 3.5

EC-61
COMPONENT PARTS INSPECTION

LPG Injector
1. Check resistance between terminals 1 and 2.
Resistance: Approx. 1 (at room temperature)
2. Remove fuse cover, and then check fuse for open.

CAUTION:
Do not apply voltage to LPG injector.

LPG Assistance Injector

Check resistance between terminals 1 and 2.
Resistance: Approx. 27 (at room temperature)
Apply battery voltage directly to terminals 1 and 2, and
then check solenoid operation.
• Apply battery voltage directly between terminals 1 and
2: Continuity should exist.
• No voltage: Continuity should not exist.

PTC Heater (Integrated with vaporizer)

Check the resistance between PTC heater terminal and ground.
Resistance:
1.5 - 2.0 (Engine coolant temperature 25 C (77 F)).

A/C System
WITH SERVICE TOOL
Confirm the service tool monitor.
Monitor item A/C switch OFF A/C switch ON
A/C signal OFF ON
A/C relay OFF ON

WITHOUT SERVIE TOOL

Check voltage between A/C control module terminal 100, 105 and
ground.
Terminal Signal name A/C switch ON
100 A/C switch Approx. 0V
105 A/C relay Approx. 12V

EC-62
 PCV GAS RECIRCULATION DEVICE

PCV GAS RECIRCULATION DEVICE System Diagram

Component Parts Inspection

Positive Carter Ventilation (PCV) valve
1. At idle, remove PCV valve together with hoses from rocker
cover.
2. Check if hissing sound is heard from the air passage when PCV
valve is operating normally.

ECM0144

3. Check air flow through the PCV valve and sucking air to/from
the INT end.
Blowing air: No air flow
Sucking air: Air flow exists

ECM0145

EC-63
 ECM COMPONENTS

ECM COMPONENTS Removal and Installation

ECM

CAUTION:
Disconnect the negative battery cable from the battery.
1. Disconnect ECM connector.
2. Remove ECM together with ECM bracket.
3. Remove ECM bracket.
4. Install in the reverse order of removal.

CAUTION:
Perform “Throttle Valve Closed Position Learning and Idle Air
Volume Learning” after installation if replacing ECM. (Refer to
EC-54, “Throttle Valve Closed Position Learning and Idle Air
Volume Learning”.)

CRANKSHAFT POSITION SENSOR (POS)

1. Remove fan.
2. Remove harness connector.
3. Remove crankshaft position sensor (POS).
NOTE:
• Make sure that there is no foreign material on sensor flange, O-
rings, and cylinder block.
• Keep away from magnetized objects.
• Make sure that the sensor is inserted securely into front cover
ECM0385 before tightening bolts.

CAMSHAFT POSITION SENSOR (PHASE)

1. Remove fan.
2. Remove harness connector.
3. Remove camshaft position sensor (PHASE).
NOTE:
• Make sure that there is no foreign material on sensor flange, O-
rings, and chain housing.
• Keep away from magnetized objects.
• Make sure that the sensor is inserted securely into cylinder
ECM0386 head front cover before tightening bolts.

MASS AIR FLOW SENSOR

1. Remove harness connector.
2. Remove mass air flow sensor assembly from air horn.

EC-64
 ECM COMPONENTS

Removal and Installation (Cont’d)

ENGINE COOLANT TEMPERATURE SENSOR
1. Disconnect radiator drain plug, and drain coolant.

CAUTION:
Make sure to drain when the coolant temperature is cold.
2. Remove harness connector.
3. Remove coolant temperature sensor using a socket specially
designed for removing and installing coolant temperature
sensors [commercially available: Thermosensor Socket
manufactured by KTC (part No.: B20T-19)] and similar parts.
ECM0387

HEATED OXYGEN SENSOR (WITH HEATED OXYGEN SENSOR

HEATER)
1. Remove harness connector from heated oxygen sensor.
2. Remove heated oxygen sensor using a socket designed for
heated oxygen sensor removal and installation (Service tool).

CAUTION:
Handle it carefully and avoid impacts.

EC-65