ES–100 3MZ-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

DTC P0110 Intake Air Temperature Circuit Malfunction

DTC P0112 Intake Air Temperature Circuit Low Input

DTC P0113 Intake Air Temperature Circuit High Input

DESCRIPTION
Fig. 1
Resistance
(kΩ)
ES
Acceptable

°C
Temperature
(°F)
A067628E10

The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, monitors the IAT.
The IAT sensor has a built in thermistor with a resistance that varies according to the temperature of the
intake air. When the IAT is low, the resistance of the thermistor increases. When the temperature is high,
the resistance drops. These variations in resistance are transmitted to the ECM (Included in ECM) as
voltage changes (See Fig. 1).
The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.
Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor
changes, according to changes in the IAT, the voltage at terminal THA also varies. Based on this signal,
the ECM increases the fuel injection volume when the engine is cold to improve drivability.
HINT:
When any of DTCs P0110, P0112 and P0113 are set, the ECM enters fail-safe mode. During fail-safe
mode, the IAT is estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition
is detected.
DTC No. Proceed to DTC Detection Condition Trouble Area
Open or short in Intake Air Temperature (IAT) sensor • Open or short in IAT sensor circuit
P0110 Step 1 circuit for 0.5 seconds • IAT sensor (built into MAF meter)
(1 trip detection logic) • ECM
• Short in IAT sensor circuit
Short in Intake Air Temperature (IAT) sensor circuit
P0112 Step 4 • IAT sensor (built into MAF meter)
for 0.5 seconds (1 trip detection logic)
• ECM
• Open in IAT sensor circuit
Open in Intake Air Temperature (IAT) sensor circuit
P0113 Step 2 • IAT sensor (built into MAF meter)
for 0.5 seconds (1 trip detection logic)
• ECM
 3MZ-FE ENGINE CONTROL SYSTEM – SFI SYSTEM ES–101

HINT:
When any of these DTCs are set, check the IAT by entering the following menus on the intelligent tester:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / INTAKE AIR.
Temperature Displayed Malfunction
-40°C (-40°F) Open circuit
140°C (284°F) or higher Short circuit

MONITOR DESCRIPTION
The ECM monitors the sensor voltage and uses this value to calculate the Intake Air Temperature (IAT).
When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a
malfunction in the IAT sensor and sets a DTC.
Example:
If the sensor output voltage is -40°C (-40°F) for 0.5 seconds or more, the ECM determines that there is an ES
open in the IAT sensor circuit, and sets DTC P0113. Conversely, if the output voltage is more than 140°C
(284°F) for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets
DTC P0112.
If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.

MONITOR STRATEGY
P0110: Intake air temperature sensor open/short (Fluctuating)
Related DTCs P0112: Intake air temperature sensor short (Low electrical voltage)
P0113: Intake air temperature sensor open (High electrical voltage)
Required Sensors/Components (Main) Intake Air Temperature (IAT) sensor
Required Sensors/Components (Related) -
Frequency of Operation Continuous
Duration 0.5 seconds
MIL Operation Immediate
Sequence of Operation None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not present None

TYPICAL MALFUNCTION THRESHOLDS

P0110:
Intake air temperature sensor voltage Less than 0.18 V or more than 4.91 V

P0112:
Intake air temperature sensor voltage Less than 0.18 V

P0113:
Intake air temperature sensor voltage More than 4.91 V

COMPONENT OPERATING RANGE

Intake air temperature sensor voltage 0.18 V to 4.91 V [-40 to 140°C (-40 to 284°F)]
 ES–102 3MZ-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

WIRING DIAGRAM
M1 ECM
Intake Air Temperature Sensor
(Built in Mass Air Flow Meter)
5V

R
4 20
THA L-B THA
E8

5 5 28
E2 W-B L BR E2
IM1 E8

ES
G039260E01

HINT:
• If other DTCs relating to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may have an open circuit.
• Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition
information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame
data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if
the air-fuel ratio was lean or rich, and other data, from the time the malfunction occurred.

1 READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (INTAKE AIR

TEMPERATURE)

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch ON.
(c) Turn the tester ON.
(d) Enter the following menus: DIAGNOSIS / ENHANCED
OBD II / DATA LIST / PRIMARY / INTAKE AIR.
(e) Read the value displayed on the tester.
Standard:
Same as actual Intake Air Temperature (IAT).
Result
Temperature Displayed Proceed to
-40 °C (-40°F) A
140°C (284°F) or higher B
Same as actual IAT C

HINT:
• If there is an open circuit, the intelligent tester indicates -
40°C (-40°F).
• If there is a short circuit, the intelligent tester indicates
140°C (284°F) or higher.
B Go to step 4

C CHECK FOR INTERMITTENT PROBLEMS

 3MZ-FE ENGINE CONTROL SYSTEM – SFI SYSTEM ES–103

2 READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN
WIRE HARNESS)

(a) Disconnect the M1 Mass Air Flow (MAF) meter

M1 connector.
MAF Meter ECM
(b) Connect terminals THA and E2 of the MAF meter wire
harness side connector.
(c) Connect the intelligent tester to the DLC3.
THA (d) Turn the ignition switch ON.
(e) Turn the tester ON.
E2 (f) Enter the following menus: DIAGNOSIS / ENHANCED ES
OBD II / DATA LIST / PRIMARY / INTAKE AIR.
(g) Read the value displayed on the tester.
Wire Harness Side: Standard:
140°C (284°F) or higher
(h) Reconnect the MAF meter connector.
M1 MAF Meter
OK CONFIRM GOOD CONNECTION TO
SENSOR. IF OK, REPLACE MASS AIR FLOW
METER

THA E2
A107690E03

NG
 ES–104 3MZ-FE ENGINE CONTROL SYSTEM – SFI SYSTEM

3 READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR OPEN IN
ECM)

(a) Disconnect the M1 MAF meter connector.

(b) Connect terminals THA and E2 of the E8 ECM
connector.
ECM HINT:
M1 MAF Meter Before checking, do visual and contact pressure checks
on the ECM connector.
THA
(c) Connect the intelligent tester to the DLC3.
(d) Turn the ignition switch ON.
E2 (e) Turn the tester ON.
ES (f) Enter the following menus: DIAGNOSIS / ENHANCED
OBD II / DATA LIST / PRIMARY / INTAKE AIR.
(g) Read the value displayed on the tester.
THA E2 Standard:
140°C (284°F) or higher
(h) Reconnect the MAF meter connector.
OK REPAIR OR REPLACE HARNESS OR
CONNECTOR

E8 ECM

A096474E03

NG

CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM

4 READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN
WIRE HARNESS)

(a) Disconnect the M1 MAF meter connector.

M1 ECM (b) Connect the intelligent tester to the DLC3.
MAF Meter (c) Turn the ignition switch ON.
(d) Turn the tester ON.
(e) Enter the following menus: DIAGNOSIS / ENHANCED
THA OBD II / DATA LIST / PRIMARY / INTAKE AIR.
E2 (f) Read the value displayed on the tester.
Standard:
-40°C (-40°F) or higher
A084869E21 (g) Reconnect the MAF meter connector.
OK REPLACE MASS AIR FLOW METER

NG
 3MZ-FE ENGINE CONTROL SYSTEM – SFI SYSTEM ES–105

5 READ VALUE OF INTELLIGENT TESTER OR OBD II SCAN TOOL (CHECK FOR SHORT IN
ECM)

(a) Disconnect the E8 ECM connector.

(b) Connect the intelligent tester to the DLC3.
(c) Turn the ignition switch ON.
(d) Turn the tester ON.
(e) Enter the following menus: DIAGNOSIS / ENHANCED
OBD II / DATA LIST / PRIMARY / INTAKE AIR.
(f) Read the value displayed on the tester.
Standard:
-40°C (-40°F) or higher
(g) Reconnect the ECM connector. ES
E8 ECM OK REPAIR OR REPLACE HARNESS OR
CONNECTOR
M1 MAF Meter ECM

THA
E2

A096476E09

NG

REPLACE ECM