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2006 Lexus GS 300 3.0L Eng

VARIABLE GEAR RATIO STEERING SYSTEM

PRECAUTION

CAUTION: If the negative (-) battery cable has been

disconnected, initialize the following systems when the
cable is reconnected.
VARIABLE GEAR RATIO STEERING SYSTEM
System

See procedure

Clearance Sonar System

INITIALIZATION

Power Window Control System

INITIALIZATION

Sliding Roof System

INITIALIZATION

Variable Gear Ratio Steering System

INITIALIZATION

1. TROUBLESHOOTING PRECAUTIONS
a. If the problem is caused by a poor connection of a terminal or poor installation of a part,
reconnecting the terminal, or removing and reinstalling the part may solve the problem, or may
temporarily return the system to normal.
b. To specify the cause of the problem, check for DTCs or confirm vehicle operating conditions
when the problem occurred and note them down before disconnecting connectors or removing
parts.
c. Be sure to check for DTCs in other systems as the problem may be caused by a malfunction in
another system.
d. DTCs may be stored in the EPS and/or ECB systems due to VGRS system inspections. Check
for DTCs in the EPS and ECB systems and clear any output codes after inspecting the VGRS
system.
e. When the engine switch is turned on/off, system start-up/stop operation is performed. At this
time, a small operating sound can be heard and the steering wheel slightly moves in a turning
direction.
f. If "INVALID" is displayed for "STRAIGHT ANG FLG" in the data list, the VGRS system does not
operate.
g. If the steering wheel is turned left and right with the engine switch off, a noise can be heard.
However, this is not a malfunction.
2. HANDLING AND OPERATIONAL PRECAUTIONS
a. Removal and installation of the steering control ECU, steering actuator, and each sensor must
be performed with the engine switch off unless specified.
b. If the steering control ECU, steering actuator, or a sensor is removed and installed, perform the
test mode inspection, check for DTCs, and confirm that the normal system code is output.
c. If the engine switch is turned on (IG) with the steering control ECU connector disconnected,
DTCs may be stored in the EPS and/or ECB systems. Check for DTCs in those systems and
clear any output codes after completing repair.
3. PRECAUTIONS FOR REPLACEMENT OF STEERING SYSTEM PARTS
a. If the steering control ECU or steering actuator is replaced, perform actuator angle neutral point
calibration and initialization.
b. The steering control ECU cannot be disassembled or repaired. If there is any problem with the

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steering control ECU, replace with a new one.

4. PRECAUTIONS FOR STEERING WHEEL OFF-CENTER

NOTE: If the steering wheel is still off-center

after completing steering angle sensor initialization
(See INITIALIZATION ), perform VGRS system
calibration (See INITIALIZATION ).
HINT:
The steering wheel may become off-center under any of the following conditions.
These conditions do not indicate a malfunction.
1. The steering wheel is turned when the engine switch is off.
2. The steering wheel is turned quickly.
3. The steering wheel is turned to the left or right lock position.
If the steering wheel is off-center, drive the vehicle at 35 km/h (22 mph) or more for 5 seconds
or more, or turn the steering wheel to the left and right with the vehicle stopped or while driving
at low speeds. This may center the steering wheel.
5. CONDITIONS UNDER WHICH VGRS SYSTEM DOES NOT OPERATE
a. The VGRS system does not operate under any of the following conditions:
a. Power supply voltage is low or too high.
b. A fail-safe function is operating to protect the system from overheating. (System control
is suspended to prevent the motor in the steering actuator and the steering control
ECU from overheating. If the temperatures of the motor and ECU drop, the system will
return to normal.)
c. The vehicle is exposed to extremely low temperatures. (If the ambient temperature
becomes approximately -30C, system control will be suspended.)

NOTE: If any of the above occurs,

perform steering angle sensor initialization
(See INITIALIZATION ).
PARTS LOCATION

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Fig 1: Identifying Steering Column Parts Location

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

SYSTEM DIAGRAM

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Fig 2: System Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

COMMUNICATION METHOD SPECIFICATION

Transmitting ECU
(Transmitter)
Steering Angle

Receiving ECU
Sensor Steering
Control ECU

Signals
Steering wheel angle signal

Communication
method
CAN

Tire angle (during straight

ahead driving) signal

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Steering Angle
Sensor

Steering Control
ECU

Steering wheel angle signal

ECM

Steering Control
ECU

Engine speed signal

Deceleration
Sensor

Steering Control
ECU

Deceleration sensor signal

Yaw Rate Sensor

Steering Control
ECU

Yaw rate signal

Serial
communication
CAN

CAN

CAN

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Skid Control ECU

Steering Control
ECU

Vehicle speed signal

CAN

Steering cooperative
control level signal
Steering Control
ECU

Skid Control ECU

Steering Control
ECU

Power Steering
ECU

Steering actuator operating

angle signal

Steering actuator operating

angle signal

CAN

CAN

Steering cooperative
control level signal
Steering Control
ECU (*1)

Combination Meter

Warning information signal

CAN - BEAN

HINT:
*1: Warning information signals are transmitted via the following route:
Steering control ECU --> (CAN) --> Power steering ECU --> (CAN) --> Gateway ECU --> (BEAN) --> Combination
meter
SYSTEM DESCRIPTION
1. GENERAL DESCRIPTION
a. The VGRS (Variable Gear Ratio Steering) system controls the steering angle in accordance with
vehicle speed. The system is controlled by the steering control ECU which operates the steering
actuator mounted on the steering intermediate shaft. The operating angle of the steering actuator
is added to the steering angle of the intermediate shaft in order to vary the turning angle of the
front wheels in accordance with vehicle speed.
b. When the VGRS system is operating normally, the steering wheel can be turned approximately
2.7 turns from lock to lock, with the engine running and the vehicle stopped.
c. If a malfunction occurs in the VGRS system, steering actuator operation will immediately stop
and the input and output shafts will be directly connected to enable the conventional steering
mechanism to operate, maintaining steering function (fail-safe). At the same time, the master
warning light (VGRS) will come on to inform the driver of the malfunction.
2. FUNCTIONS OF COMPONENTS
a. Functions of VGRS system components
FUNCTIONS OF COMPONENTS
Component

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Function

Steering
Control ECU

Calculates the steering gear ratio based on tire angle signals and vehicle
speed signals. Drives the steering actuator based on calculation results of
steering cooperative control received from the skid control ECU, and of
steering gear ratio control.

Steering
Actuator

Drives the motor using the output current from the steering control ECU to
change the output shaft angle.

Rotation Angle
Sensor

Outputs the motor rotation angle to the steering control ECU.

Steering Angle
Sensor

Outputs the steering wheel angle to the steering control ECU.

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Master
Warning Light
Multiinformation
Display

Located on the combination meter ECU. Comes on or blinks in accordance

with system conditions to inform the driver of system malfunctions.
Located on the combination meter ECU. Displays a warning message to inform
the driver of system malfunctions.

HOW TO PROCEED WITH TROUBLESHOOTING

HINT:
The intelligent tester can be used in steps 3, 4, 5, 7 and 11.
1. VEHICLE BROUGHT TO WORKSHOP
NEXT
2. CUSTOMER PROBLEM ANALYSIS
a. Confirm problem symptoms.
NEXT
3. CHECK MULTIPLEX COMMUNICATION SYSTEM
a. Check for DTCs.
MULTIPLEX COMMUNICATION SPECIFICATION
DTC is not output.

DTC is output.

B : GO TO MULTIPLEX COMMUNICATION SYSTEM

A : GO TO NEXT STEP
4. CHECK CAN COMMUNICATION SYSTEM
a. Check for DTCs.
MULTIPLEX COMMUNICATION SPECIFICATION
DTC is not output.

DTC is output.

B : GO TO CAN COMMUNICATION SYSTEM

A : GO TO NEXT STEP
5. CHECK DTC
a. Check for DTCs.
a. Record the DTCs.
b. Clear the DTCs.
c. Recheck for DTCs.
a. Simulate the malfunction and check if the DTCs are output again (See TERMINALS
OF ECU ).
TERMINALS OF ECU SPECIFICATION

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DTC is output.

DTC is not output.

DTCs are not output, and the malfunction can not be simulated or
checked.

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B : GO TO STEP 10
C : SYMPTOM SIMULATION
A : GO TO NEXT STEP
6. DTC CHART
NEXT
7. CIRCUIT INSPECTION
NEXT
8. REPAIR
NEXT
9. CONFIRMATION TEST
NEXT
END
10. PROBLEM SYMPTOMS TABLE
NEXT
11. CIRCUIT INSPECTION
NEXT
12. CONFIRMATION TEST
NEXT
END
INITIALIZATION
1. STEERING ANGLE SENSOR INITIALIZATION (to obtain a tire angle (during straight-ahead driving)
signal)
a. Turn the engine switch on (IG), and check that the master warning light and VSC/ABS warning
lights illuminate for a few seconds.

NOTE: If the warning lights remain on or

blink, repair he applicable system.
b. Drive the vehicle on a straight road at 35 km/h (22 mph) or more for 5 seconds or longer.
HINT:
a. At this point, the steering wheel will still remain off-center by 5 to 10 degrees.
b. In this step, the neutral position of the steering wheel is restored from the steering
control ECU memory.
c. Confirm that steering angle sensor initialization is completed (when using the intelligent tester).
a. Enter the VGRS menu using the intelligent tester. Select "STRAIGHT ANG FLG" from
"DATA LIST". Check if the steering angle sensor has obtained a tire angle (during
straight-ahead driving) signal.
Standard:
"VALID" is displayed on the tester screen.
d. Confirm that steering angle sensor initialization is completed (when not using the intelligent
tester).

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a. Drive the vehicle on a straight road at 60 km/h (37 mph) or more for 30 seconds or
longer.
b. Stop the vehicle (engine running).
c. Slowly turn the steering wheel from lock to lock.
d. If it turns approximately 2.7 turns, steering angle sensor initialization is completed. If it
turns approximately 3.2 turns, steering angle sensor initialization is not completed.

NOTE: If the steering wheel turns

approximately 3.2 turns, perform step (b)
again.

Fig 3: Identifying Master Warning Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

CALIBRATION

NOTE: Use this procedure to center the steering

wheel if:
The steering actuator has been replaced,
The steering control ECU has been replaced,
The steering column or gear has been
disconnected,
or
The steering wheel is still off-center after
completing the steering angle sensor
initialization.

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1. VGRS SYSTEM CALIBRATION PROCEDURE (USING SST CHECK WIRE)

1. FACE TIRES STRAIGHT AHEAD

NOTE: Drive the vehicle to confirm that the

steering wheel is centered.
NEXT
2. CHECK DTCs
a. Check for DTCs (See TERMINALS OF ECU ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC C1591/51 is not output.

DTC C1591/51 is output.

B : Go to step 4
A : GO TO NEXT STEP
3. PERFORM ACTUATOR ANGLE INITIALIZATION

NOTE: Complete steps (d) to (h) within 1

minute.
a. Turn the engine switch on (IG).
b. Start the engine.
c. Center the steering wheel.
d. Using SST check wire, connect terminals TS and CG, and TC and CG of the DLC3.
SST 09843-18040
e. Disconnect the SST check wire from terminal TS of the DLC3, and turn the steering
wheel to the left 180 or more.
f. Connect the SST check wire to terminal TS of the DLC3.
g. Disconnect the SST check wire from terminal TC of the DLC3, and turn the steering
wheel to the right 180 or more.
h. Connect the SST check wire to terminal TC of the DLC3.

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Fig 4: Identifying DLC3 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:
When the master warning light (VGRS) comes on, DTC C1591/51 is memorized.
i. Disconnect the SST check wire from the DLC3.
j. Turn the engine switch off.
NEXT
Go to step 1
4. FACE TIRES STRAIGHT AHEAD
a. Confirm that the steering wheel is centered when facing the tires straight ahead.

NOTE: Drive the vehicle to confirm that

is steering wheel is centered.
Result
RESULT SPECIFICATION
Result

Proceed to

Steering wheel is off-center.

Steering wheel is centered.

B : Go to step 8

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A : GO TO NEXT STEP
5. UNLOCK STEERING ACTUATOR

NOTE: Do not start the engine.

a. Turn the engine switch off.
b. Disconnect the negative (-) terminal cable from the battery.
c. Disconnect the K26 connector from the steering actuator.
d. Connect a jumper wire from terminal LV+ to the positive (+) battery terminal and
another jumper wire from terminal LG+ to the negative (-) battery terminal.

NOTE: Do not apply voltage for more

than 3 minutes.

Fig 5: Identifying K26 Connector From Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NEXT
6. STEERING CENTER ADJUSTMENT
a. Center the steering wheel.

NOTE: If the spiral cable of the airbags

and VGRS system is not centered when
the steering wheel is installed, release the
system lock and center the spiral cable
(See SPIRAL CABLE ). Slowly turn the
steering wheel to the left. Turn it to the right

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approximately 2 turns from the point where

resistance begins to be felt (the end of the
spiral cable) while steering. This will center
the spiral cable. (If excessive force is
applied to the end of the spiral cable, the
cable may break.)
NEXT
7. LOCK STEERING ACTUATOR
a. Disconnect the positive (+) and negative (-) battery terminal cables from the steering
actuator.
b. Connect the K26 connector to the steering actuator.
c. Connect the negative (-) terminal cable to the battery.
d. Turn the steering wheel approximately 3 to the left and right. Confirm that the reaction
force can be felt.

NOTE:
a. If the above procedures are not
followed correctly, a DTC will be
detected. If a DTC is detected,
perform the above procedures
again and then check for DTCs.
b. Perform these procedures with
the engine switch off.
NEXT : Go to step 1
8. ADJUST ACTUATOR ANGLE
HINT:
Activating and ending test mode will complete actuator angle adjustment.
a. Make sure the engine switch is off.

NOTE: Do not touch the steering

wheel during these procedures.
b. Using SST check wire, connect terminals TS and CG of the DLC3.
SST 09843-18040
c. Turn the engine switch on (IG).
d. Confirm that the "VGRS TEST MODE" is displayed on the multi-information display
when test mode is activated.
e. Turn the engine switch off.
f. Disconnect the SST check wire from terminals TS and CG of the DLC3.

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Fig 6: Identifying DLC3 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

g. Turn the engine switch on (IG) again.

NEXT
9. CHECK MASTER WARNING LIGHT
a. Confirm that the master warning light (VGRS) off.
b. Turn the engine switch off.
c. Confirm that master warning light (VGRS) operating normally.
NEXT
10. CHECK STEERING WHEEL OPERATION
a. Start the engine.
b. Perform the steering angle sensor initialization (See INITIALIZATION ).
c. Turn the steering wheel from lock to lock to check that it rotates approximately 2.7
turns.
d. Drive vehicle to confirm steering wheel is centered.
NEXT
END
2. VGRS SYSTEM CALIBRATION PROCEDURE (USING INTELLIGENT TESTER)
1. FACE TIRES STRAIGHT AHEAD

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NOTE: Drive the vehicle to confirm that the

steering wheel is centered.
NEXT
2. PERFORM VGRS SYSTEM CALIBRATION
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and turn the intelligent tester on.
c. Select and perform "STEERING ANGLE ADJ" from the VGRS menu on the intelligent
tester display.
Fig 7: Connecting Intelligent Tester To DLC3

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

d. Press the "ENTER" key.

NOTE: Press the "ENTER" key even if

DTC C15B4/71 is output.

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Fig 8: Intelligent Tester Display - Press "ENTER" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

e. Press the "ENTER" key.

NOTE: Ensure that the engine switch

is off.

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Fig 9: Intelligent Tester Display - Press "ENTER" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

f. Press the "YES" key.

Fig 10: Intelligent Tester Display - Press "YES" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

g. Press the "ENTER" key.

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NOTE: If the spiral cable of the airbags

and VGRS system is not centered when
the steering wheel is installed, release the
system lock and center the spiral cable
(See SPIRAL CABLE ). Slowly turn the
steering wheel to the left. Turn it to the right
approximately 2 turns from the point where
resistance begins to be felt (the end of the
spiral cable) while steering. This will center
the spiral cable. (If excessive force is
applied to the end of the spiral cable, the
cable may break.)

Fig 11: Intelligent Tester Display - Press "ENTER" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

h. Press the "ENTER" key.

NOTE: Do not touch the steering

wheel during these procedures.

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Fig 12: Intelligent Tester Display - Press "ENTER" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

i. Press the "ENTER" key.

Fig 13: Intelligent Tester Display - Press "ENTER" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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j. Press the "ENTER" key.

NOTE: Do not touch the steering

wheel during these procedures.

Fig 14: Intelligent Tester Display - Press "ENTER" Key

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

k. The remaining time is displayed and the display switches automatically to the next
screen.

NOTE: Do not touch the steering

wheel during these procedures.

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Fig 15: Intelligent Tester Display - VGRS System Calibration

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

l. Check that VGRS system calibration is completed normally.

m. Select "ENTER" to return the display to the "MENU" screen.
Fig 16: Intelligent Tester Display - Steering Angle

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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NEXT
3. CHECK MASTER WARNING LIGHT
a. Confirm that the master warning light (VGRS) off.
b. Turn the engine switch off.
c. Disconnect the intelligent tester from the DLC3.
d. Confirm that master warning light (VGRS) operating normally.
NEXT
4. CHECK STEERING WHEEL OPERATION
a. Start the engine.
b. Perform the steering angle sensor initialization (See INITIALIZATION ).
c. Turn the steering wheel from lock to lock to check that it rotates approximately 2.7
turns.
d. Drive vehicle to confirm steering wheel is centered.
NEXT
END
PROBLEM SYMPTOMS TABLE
HINT:
If a normal system code is displayed during the DTC check but the problem still occurs, check the circuits for each
problem symptom in the order given in the table below and proceed to the relevant troubleshooting page.
Variable Gear Ratio Steering System
PROBLEM SYMPTOMS CHART
Symptom

See

Steering wheel is off-center or

deviates from neutral position

DTC U0100/56 LOST

COMMUNICATION WITH ECM / PCM
"A"

Only if the following (1 to 4) is all

normal and the problem is still
occurring, replace the steering
control ECU.

REMOVAL

1. Actuator temperature is
abnormal

DTC U0123/56 LOST

COMMUNICATION WITH YAW RATE
(DECELERATION) SENSOR
MODULE

2. IG power source circuit

DTC C15B4/71 ECU MALFUNCTION

3. IG or PIG power supply circuit

WIRING DIAGRAM

4. Power steering system (check

steering effort)

ON-VEHICLE INSPECTION

Steering angle differs

between left and right

Steering angle differs between left

and right

STEERING ANGLE DIFFERS

BETWEEN LEFT AND RIGHT

Steering wheel vibrates

or abnormal noise is
heard from steering
wheel

Steering wheel vibrates or

abnormal noise is heard from
steering wheel

STEERING WHEEL VIBRATES OR

ABNORMAL NOISE IS HEARD FROM
STEERING WHEEL

Steering wheel is
off-center

VGRS system stops or

does not operate

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Suspected area

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Master warning light

(VGRS) malfunction

Master warning light circuit

MASTER WARNING LIGHT

MALFUNCTION

TERMINALS OF ECU
HINT:
Inspect the connectors from the back side while they are connected.
Fig 17: Identifying Terminals Of ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

TERMINAL DESCRIPTION SPECIFIED CONDITION CHART

Symbols
(Terminal No.)

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Wiring Color

Terminal Description

Condition

Specified
Condition

AFS+ (A40-2)
- PGND
(A40-7)

L - W-B

CAN communication line (to AFS

system)

Engine switch on
(IG)

Pulse
generation

IG (A40-3) PGND (A40-7)

B-Y - W-B

Power supply (ECU-IG fuse)

Engine switch on
(IG)

10 to 14 V

CAN+ (A40-4)
- CAN(A40-9)

B-W

Local CAN communication

Engine switch on
(IG)

Pulse
generation

AFS- (A40-5) PGND (A40-7)

Y - W-B

CAN communication line (to AFS

system)

Engine switch on
(IG)

Pulse
generation

PGND (A40-7)
- Body ground

W-B -

Body Ground

Always

Below 1

PIG (A40-8) PGND (A40-7)

R - W-B

Power supply (VGRS fuse)

Engine switch on
(IG)

10 to 14 V

+BI (A40-10) PGND (A40-7)

GR - W-B

Power supply (ECU-B fuse)

Always

10 to 14 V

BMV (K69-1) PGND (A40-7)

W - W-B

Steering actuator motor signal (V

phase)

Engine start

Sine wave

BMU (K69-2) PGND (A40-7)

B - W-B

Steering actuator motor signal (U

phase)

Engine start

Sine wave

BMW (K69-3)
- PGND
(A40-7)

R - W-B

Steering actuator motor signal (W

phase)

Engine start

Sine wave

SG (K69-6) PGD2 (K69-8)

BR - W-B

Steering actuator motor signal shield

ground

Always

Below 1

PGD2 (K69-8)
- Body ground

W-B Body
ground

Steering control ECU ground

Always

Below 1

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+BO (K70-1) PGND (A40-7)

LG - W-B

Steering sensor power supply line

Always

10 to 14 V

LV (K70-3) PGND (A40-7)

Y - W-B

Power source for steering actuator

lock

Engine switch on
(IG)

10 to 14 V

S1 (K70-41) PGND (A40-7)

W - W-B

Steering actuator motor rotation

angle sensor signal

Engine switch on
(IG)

Sine wave

RV (K70-6) PGND (A40-7)

B - W-B

Steering actuator resolver excitation

output voltage

Engine switch on
(IG)

Sine wave

SIL (K70-7) PGND (A40-7)

R - W-B

Diagnostic communication signal

Engine switch on
(IG)

Pulse
generation

CANH (K70-9)
- CANL
(K70-20)

P-V

Global CAN communication

Engine switch on
(IG)

Pulse
generation

SS1- (K70-10)
- PGND
(A40-7)

L - W-B

Steering angle sensor signal

Engine switch on
(IG), turn the
steering wheel

Pulse
generation

LG (K70-12) PGND (A40-7)

L - W-B

Steering actuator lock ground

Engine start

Pulse
generation

S2 (K70-14) PGND (A40-7)

R - W-B

Steering actuator motor rotation

angle sensor signal

Engine switch on
(IG)

Sine wave

RG (K70-15) PGND (A40-7)

G - W-B

Steering actuator resolver common

ground

Always

Below 1

SS2+
(K70-16) PGND (A40-7)

Shielded W-B

Ground for steering actuator motor

rotation angle sensor signal wire and
control signal wire shield wire

Engine switch on
(IG)

Pulse
generation

SS1+
(K70-19) PGND (A40-7)

LG - W-B

Steering angle sensor signal

Engine switch on
(IG), turn the
steering wheel

3 to 4 V

DIAGNOSIS SYSTEM
1. DIAGNOSTIC SYSTEM
a. Inspect the battery voltage.
Standard:
11 to 14 V
HINT:
If the voltage is below 11 V, recharge the battery before proceeding.

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Fig 18: Identifying DLC3 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Check the DLC3.

a. The steering control ECU uses CAN and ISO 9141-2 as its communication protocol.
The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO
9141-2 format. Verify the conditions listed in the table below.
TERMINAL DESCRIPTION SPECIFIED CONDITION CHART

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Symbols (Terminals
No.)

Terminal
description

Condition

Specified
condition

SIL (7) - SG (5)

Bus "+" line

During
transmission

Pulse
generation

CG (4) - Body
ground

Chassis ground

Always

Below 1

SG (5) - Body
ground

Signal ground

Always

Below 1

BAT (16) - Body

ground

Battery positive

Always

11 to 14 V

CANH (6) - CANL

(14)

HIGH-level CAN
bus line

Engine switch
off

54 to 67

CANH (6) - Battery

positive

HIGH-level CAN
bus line

Engine switch
off

1 M or
higher

CANH (6) - CG (4)

HIGH-level CAN
bus line

Engine switch
off

3 k or higher

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CANL (14) Battery positive

LOW-level CAN
bus line

Engine switch
off

1 M or
higher

CANL (14) - CG (4)

LOW-level CAN
bus line

Engine switch
off

3 k or higher

HINT:
If the display shows a communication error message when you connect the cable of
the intelligent tester to the DLC3, turn the engine switch on (IG) and operate the
intelligent tester, there is a problem on either the vehicle side or the tool side.
a. If communication is normal when the tool is connected to another vehicle,
inspect the DLC3 on the original vehicle.
b. If communication is still not possible when the tool is connected to another
vehicle, the problem is probably in the tool itself. Consult the Service
Department listed in the tool's instruction manual.
c. If the problem still occurs after the above inspection is performed, there may
be a problem with the DLC3 connector.
2. FUNCTION OF WARNING LIGHT AND MESSAGE
a. If a malfunction occurs during system operation, the master warning light (VGRS) on the
combination meter assembly will come on and "CHECK VGRS" will be displayed on the multiinformation display to inform the driver of the system malfunction.
Fig 19: VGRS Screen Display

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

3. DTCs
a. Normal mode.
a. DTCs are memorized in the steering control ECU and read by using the intelligent
tester (See TERMINALS OF ECU ).
b. Test mode.
a. By switching from normal mode to test mode, the steering angle sensor can be
inspected (See DTC CHECK / CLEAR ).
HINT:

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Whether the system is in diagnostic mode or test mode can be checked from the
indication on the multi-information display. For details of the indication and how to
check, refer to "DTC CHECK / CLEAR" (see DTC CHECK / CLEAR ).
Fig 20: Connecting Intelligent Tester To DLC3

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

4. CHECK MASTER WARNING LIGHT

a. Turn the engine switch on (IG).
b. Check that the master warning light (VGRS) comes on for 2 seconds.
HINT:
If the master warning light (VGRS) check result is not normal, proceed to troubleshooting of the
warning light circuit.
TROUBLE AREA CHART
Trouble Area
Master warning light circuit

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See procedure
MASTER WARNING LIGHT MALFUNCTION

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Fig 21: Identifying Master Warning Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

DTC CHECK / CLEAR

1. DTC CHECK (USING INTELLIGENT TESTER)
HINT:
If the DTC check/clear is performed using the intelligent tester, 2-digit codes will also be displayed on the
multi information display.
a. Check for DTCs.
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and turn the intelligent tester on.
c. Check the DTCs by following the prompts on the tester screen. (5-digit DTCs only will
be displayed.)
HINT:
Refer to the intelligent tester's operator's manual for further details.
b. Clear the DTCs.
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG).
c. Clear the DTCs by following the prompts on the tester screen.
HINT:
Refer to the intelligent tester's operator's manual for further details.

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Fig 22: Connecting Intelligent Tester To DLC3

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

2. DTC CHECK (USING SST CHECK WIRE)

HINT:
The master warning light comes on in diagnostic mode.
a. Check for DTCs.
a. Using SST check wire, connect terminals TC and CG of the DLC3.
SST 09843-18040
b. Turn the engine switch on (IG).
c. "DIAG VGRS" is displayed on the multi information display and the system starts
searching for a malfunction.

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Fig 23: Identifying DLC3 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

d. If the system is normal, "DIAG VGRS OK" is displayed.

Fig 24: DIAG VGRS OK Screen Display

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

e. If the system has a malfunction, "DIAG VGRS xx" is displayed. ("xx" is a 2-digit DTC.)
b. Clear the DTCs.

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a. Turn the engine switch on (IG).

Fig 25: DIAG VGRS xx Screen Display

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Using SST check wire, connect and disconnect terminals TC and CG of the DLC3 4
times within 8 seconds.
SST 09843-18040
c. Disconnect SST check wire from the DLC3.

NOTE: The stored yaw rate sensor

value will be cleared by the above
operation. Obtain the yaw rate sensor zero
point.
d. Turn the engine switch off.
HINT:
If the problem still exists, DTCs may not be cleared (See INITIALIZATION ).
e. Obtain the yaw rate sensor zero point.

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Fig 26: Identifying DLC3 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

FREEZE FRAME DATA

HINT:
The VGRS system stores data when a trouble code is set and can be viewed using the intelligent tester.
1. FREEZE FRAME DATA OF STEERING CONTROL ECU
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and turn the intelligent tester on.
c. Select "FREEZE FRAME DATA" from the display on the tester.
INTELLIGENT TESTER DISPLAY CHART
Intelligent Tester
Display
SPD (VSC)

Vehicle speed (VSC ECU)

Value (Unit)
Speed indicated on
speedometer (km/h)

ENGINE REV
(RPM)

Engine revolution (RPM)

MTR SOURCE
CUR

Motor power source actual

current

0 to 127.5 (A)

PIG SOURCE
VOL

PIG power source voltage

0 to 25.5 (V)

IG power source voltage

0 to 25.5 (V)

IG SOURCE VOL

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Measurement Item

Less than 300 or more then

300 (RPM)

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LOCK OUTPUT
VOL

LOCK motor output voltage

0 to 25.5 (V)

Command value DUTY for PVM

control

0 to 100 (%)

Command value DUTY for

actuator lock control

0 to 100 (%)

RES OFFSET
(SIN)

Resolver offset (SIN)

0 to 25.5 (V)

RES OFFSET
(COS)

Resolver offset (COS)

0 to 25.5 (V)

MOTOR
CURRENT U

Motor current U

-63 to 64.5 (A)

MOTOR
CURRENT V

Motor current V

-63 to 64.5 (A)

MOTOR
CURRENT W

Motor current W

-63 to 64.5 (A)

DUTY VAL
LOCK DUTY VAL

MOTOR
VOLTAGE

Motor power supply voltage

0 to 51 (V)

STEERING POS1

Steering position1

-2047 to 2048.9375 (deg)

ACTUATOR POS

Actuator position

-2047 to 2048.9375 (deg)

STR ANGL VEL

Steering wheel angle velocity

-2047 to 2048.9375
(deg/sec)

ACT TARGET
ANG1

Actuator target angle1

-2047 to 2048.9375 (deg)

ACT TARGET
ANG2

Actuator target angle2

-2047 to 2048.9375 (deg)

ACT REV SPD

Actuator revolution speed

-2047 to 2048.9375 (deg)

CHECK MODE PROCEDURE

1. TEST MODE (VGRS SENSOR SIGNAL CHECK)
HINT:
1. When the system enters test mode, "VGRS TEST MODE" is displayed on the multi-information
display.
2. Before entering test mode, check and repair any malfunctions indicated by the present DTCs of
the VGRS system.
3. By switching from normal mode to test mode, the steering angle sensor can be read.
4. When entering test mode, the steering control ECU sets all the test mode DTCs first.
5. When the mode is switched from test mode to normal mode, all the test mode DTCs will be
erased.
a. Check the test mode DTCs (using the intelligent tester).
a. Turn the engine switch off.

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Fig 27: VGRS TEST MODE Screen Display

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Connect the intelligent tester to the DLC3.

c. Turn the engine switch on (IG) and turn the intelligent tester on.
d. Read the test mode DTCs by following the prompts on the tester screen.
HINT:
Refer to the intelligent tester's operator's manual for further details.
b. Clear the test mode DTCs (using the intelligent tester).

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Fig 28: Connecting Intelligent Tester To DLC3

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

a. Turn the engine switch off.

b. Connect the intelligent tester to the DLC3.
c. Turn the engine switch on (IG) and turn the intelligent tester on.
d. Switch the system from test mode to normal mode by following the directions on the
tester screen.
HINT:
Refer to the intelligent tester's operator's manual for further details.
c. Check the test mode DTCs (using SST check wire).
a. Turn the engine switch off.

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Fig 29: Connecting Intelligent Tester To DLC3

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

b. Using SST check wire, connect terminals TS (TC) and CG of the DLC3.
SST 09843-18040
c. Turn the engine switch on (IG).
d. Read 2-digit test mode DTCs from the multi information display.

NOTE: Perform these procedures with

the vehicle stopped.
d. Clear the test mode DTCs (using SST check wire).
a. Turn the engine switch off.
b. Disconnect the SST check wire from the DLC3.
SST 09843-18040
c. Turn the engine switch on (IG).
HINT:
If the engine switch is turned on (IG) with terminals TS and CG short-circuited, the
system remains in test mode.

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Fig 30: Identifying DLC3 Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

2. TEST MODE DTC

a. If a trouble code is displayed during the DTC check, check the circuit indicated by the DTC. For
details of each code, proceed to DTC chart.
DTC DETECTION ITEM CHART
DTC No.

C15C4/74

C15C5/75

Detection Item

A steering signal indicating a tire angle of 36or

more (to the left or right) is input after transfer to
test mode. (*1)

A steering signal indicating a motor rotation

angle of 36or more (to the left or right) is input
after transfer to test mode. (*1)

Trouble Area
a. Steering
angle sensor
b. Steering
control ECU
a. Steering
angle sensor
b. Steering
control ECU

HINT:
*1: A tire angle of 36and a motor rotation angle of 36correspond to the steering wheel angle
respectively. The amount of change in tire angle and motor rotation angle is from when the mode
is changed to test mode.
DATA LIST / ACTIVE TEST
HINT:
By accessing the DATA LIST displayed on the intelligent tester, the values of switches and sensors can be read

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without removing any parts. Reading the DATA LIST is the first step of troubleshooting and is one method to shorten
labor time.
1. STEERING CONTROL ECU
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and turn the intelligent tester on.
c. Following the display on the tester, select "DATA LIST".
ITEM NORMAL CONDITION CHART

Item

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Measurement Item/Range
(Display)

Normal Condition

Diagnostic Note

SPD (VSC)

Vehicle speed (VSC

ECU)/Min.: 0 km/h, Max.:
255 km/h

Actual vehicle
speed

Speed indicated on
speedometer

ENGINE REV
(RPM)

Engine revolution
(rpm)/Less 300 or More
300

Less than 300

RPM More than
300 RPM

Engine stopped
Engine running

MTR SOURCE
CUR

Motor power source

actual current/Min.: 0 A,
Max.: 127.5 A

Less than 1 A
More than 1 A

When not turning

the steering wheel
When turning the
steering wheel

PIG SOURCE
VOL

PIG power source

voltage/Min.: 0 V, Max.:
25.5 V

9 to 16 V

Engine switch on
(IG) (Engine
stopped)

IG SOURCE
VOL

IG power source
voltage/Min.: 0 V, Max.:
25.5 V

9 to 16 V

Engine switch on
(IG) (Engine
stopped)

TERMINAL
VOL U

Terminal voltage U/Min.: 0

V, Max.: 25.5 V

0 to 16 V

Turning the
steering wheel
changes the value
(with the engine
running and the
VGRS system
operating)

TERMINAL
VOL V

Terminal voltage V/Min.: 0

V, Max.: 25.5 V

0 to 16 V

Turning the
steering wheel
changes the value
(with the engine
running and the
VGRS system
operating)

TERMINAL
VOL W

Terminal voltage W/Min.:

0 V, Max.: 25.5 V

0 to 16 V

Turning the
steering wheel
changes the value
(with the engine
running and the
VGRS system
operating)

LOCK
OUTPUT VOL

Lock motor output

voltage/Min.: 0 V, Max.:
25.5 V

9 to 16 V

Engine switch on
(IG) (Engine
stopped)

THERMISTOR
TEMP

Thermistor
temperature/Min.: -50C,
Max.: 205C

-50 to 150C

When the VGRS

system operates

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DUTY VAL

Command value DUTY

for PVM control/Min.: 0%,
Max.: 100%

0 to 100%

When the VGRS

system operates

LOCK DUTY
VAL

Command value DUTY

for actuator lock
control/Min.: 0%, Max.:
100%

Less than 10%

Engine switch on
(IG)

STRAIGHT
ANG FLG (*1)

Straight steering angle

valid flag/VALID or
INVALID

VALID or
INVALID

Immediately after
connecting the
battery terminal

ACT TEMP
EST

Actuator estimation
temperature/Min.: -50C,
Max.: 205C

-50 to 150C

When the VGRS

system operates

MTR
OVERHEAT
(*2)

Record of continuous
overheat preventive
control/Rec or Unrec

Rec or Unrec

MTR LOW
POWER (*2)

Record of low motor

power source voltage/Rec
or Unrec

Rec or Unrec

MTR HIGH
POWER (*2)

Record of high motor

power source voltage/Rec
or Unrec

Rec or Unrec

# CODE

The number of
DTCs/Max.: 0, Min.: 255

0 to 255

TEST MODE
STAT

Test mode status/Normal

mode or Test mode

Normal mode or
Test mode

MODE STATE

Mode State/00, 01, 02,

03, 04, 05, 06, 07, 08, 09,
0A, 0B, 0C, 0D, 0E, 0F,
10 00, 01, 02, 03, 04, 06,
07, 08, 09, 0A, 0B, 0C,
0D, 0E, 0F, 10

00, 01, 02, 03,

04, 05, 06, 07,
08, 09, 0A, 0B,
0C, 0D, 0E, 0F,
10 00, 01, 02,
03, 04, 06, 07,
08, 09, 0A, 0B,
0C, 0D, 0E, 0F
or 10

NOTE: *1: This data must be "VALID"

before proceeding with any steering adjustment.
If "INVALID" is displayed, perform steering
angle sensor initialization procedure.
Alternatively, if the steering actuator or steering
control ECU has been replaced, perform VGRS
system calibration (steering angle adjustment).
HINT:
*2: If "Rec" is displayed, enter the VGRS menu on the intelligent tester, select record clearance,
and follow the prompts to set to "Unrec".
DIAGNOSTIC TROUBLE CODE CHART
HINT:
If a trouble code is displayed during the DTC check, check the circuit indicated by the DTC. For details of each
code, proceed to the page for the respective "DTC No." in the following DTC chart.
Variable Gear Ratio Steering System
DIAGNOSTIC TROUBLE CODE CHART

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DTC No.
C1591/51

Detection Item
Actuator Neutral Position Calibration Undone

Trouble Area
1. Steering actuator
2. Steering control ECU

C1592/52

Actuator Neutral Position Calibration

Incomplete

1. Steering actuator
2. Steering control ECU

C1593/53

Actuator Standard Position Malfunction

C1595/55

Lost Communication with Steering Angle

Sensor Module

1. Steering actuator

1. Steering angle sensor

2. Steering control ECU
3. Wire harness and connector

C1597/57

Lost Communication between VGRS and EPS

1. Power steering ECU

2. Steering control ECU
3. CAN communication system
(Local CAN)

C15A1/61

Actuator Malfunction

1. Wire harness and connector

2. Steering actuator
3. Steering control ECU

C15A2/62

Actuator Malfunction

1. Wire harness and connector

2. Power source circuit
3. Steering actuator
4. Steering control ECU

C15A3/63

Actuator Malfunction

1. Wire harness and connector

2. Steering actuator
3. Steering control ECU

C15A4/64

Actuator Malfunction

C15A5/65

Actuator Malfunction

1. Steering actuator

1. Steering actuator
2. Steering control ECU

C15A6/62

Actuator Malfunction

1. Power source circuit

2. Wire harness and connector

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3. Steering actuator
4. Steering control ECU
C15A9/66

Lock Holder Deviation Detection

C15AA/66

Lock Mechanism Release Incomplete

C15AB/66

Lock Mechanism Insertion Malfunction

C15B1/71

ECU Malfunction

C15B2/72

ECU Malfunction

C15B3/73

ECU Malfunction

C15B4/71

ECU Malfunction

C15C1/74

Steering Angle Sensor Malfunction

1. Steering actuator

1. Steering actuator

1. Steering actuator

1. Steering control ECU

1. Steering control ECU

1. Steering control ECU

1. Steering control ECU

1. Steering angle sensor

2. CAN communication system
3. Steering control ECU

C15C2/74

Steering Angle Sensor B+ Malfunction

1. Steering angle sensor

2. CAN communication system
3. Steering control ECU

C15C3/75

Brake System Control Module Malfunction

1. Skid control ECU

2. CAN communication system
3. Steering control ECU

C15C4/74

Steering Angle Signal (Test Mode DTC)

1. Steering angle sensor

2. Steering control ECU

C15C5/75

Motor Revolution Angle Signal (Test Mode

DTC)

1. Steering angle sensor

2. Steering control ECU

C15C6/77

IG Power Supply Voltage Malfunction

1. ECU-IG fuse
2. IG circuit
3. Charging system
4. Steering control ECU

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C15C7/78

DC Motor Power Source Voltage Malfunction

1. VGRS fuse
2. Power source circuit
3. Steering control ECU

C15C8/79

Power Supply Relay Failure

1. VGRS fuse
2. Steering control ECU

U0100/56

Lost Communication with ECM / PCM "A"

1. ECM
2. CAN communication system

U0122/56

Lost Communication with Vehicle Dynamics

Control Module

1. Skid control ECU

2. CAN communication system

U0123/56

Lost Communication with Yaw Rate

(Deceleration) Sensor Module

1. Yaw rate (deceleration) sensor

2. CAN communication system

U0126/56

Lost Communication with Steering Angle

Sensor Module

1. Steering position sensor

2. CAN communication system

U0131/56

Lost Communication with Power Steering

Control Module

1. Power steering ECU

2. CAN communication system

DTC C1591/51 Actuator Neutral Position Calibration Undone

DESCRIPTION
If the steering control ECU or steering actuator is replaced, or if the tie-rod ends are adjusted, VGRS system
calibration is required. If the steering control ECU detects that steering angle adjustment is incomplete, it will store
DTC C1591/51.
DTC DETECTING CONDITION CHART
DTC No.
C1591/51

DTC Detecting Condition

The steering control ECU detects that
steering angle adjustment is incomplete.

Procedure
There is no malfunction if this DTC is not output
again after performing VGRS system calibration.

1. CHECK DTC
a. Check for DTCs (See TERMINALS OF ECU ).
OK:
DTC C1591/51 only is output.
NG : REPAIR CIRCUIT INDICATED BY DTC OUTPUT
OK : GO TO NEXT STEP
2. PERFORM VGRS SYSTEM CALIBRATION
a. Perform VGRS system calibration (See INITIALIZATION ).

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NEXT
3. CHECK DTC
a. Check for DTCs (See TERMINALS OF ECU ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC C1592/52 is output.

DTC C1593/53 is output.

B : GO TO DTC C1592/52
C : GO TO DTC C1593/53
A : END
DTC C1592/52 Actuator Neutral Position Calibration Incomplete
DESCRIPTION
The steering control ECU first checks the actuator angle neutral position calibration flag after entering test mode. If
the ECU detects that steering actuator angle neutral position calibration is incomplete twice, it will store DTC
C1592/52.
DTC DETECTING CONDITION CHART
DTC No.

C1592/52

DTC Detecting Condition

The steering control ECU detects that steering actuator angle

neutral position calibration is incomplete, twice.

Trouble Area
Steering
actuator
Steering
control ECU

1. CLEAR DTC
a. Clear the DTCs (See TERMINALS OF ECU ).
NEXT
2. PERFORM VGRS SYSTEM CALIBRATION
a. Perform VGRS system calibration (See INITIALIZATION ).
NEXT
3. CHECK DTC
a. Check for DTCs (See TERMINALS OF ECU ).
OK:
DTC C1592/52 is not output.
NG : Go to step 4
OK : END
4. CHECK DTC
a. Check for DTCs (See TERMINALS OF ECU ).

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Result
RESULT SPECIFICATION
Proceed
to

Result
DTC C15B2/72 is output.

DTC C1592/52 is output after VGRS system calibration has been performed
less than 3 times.

DTC 1592/52 is output after VGRS system calibration has been performed
3 times or more.

A : REPLACE STEERING CONTROL ECU

B : Go to step 1
C : REPLACE STEERING ACTUATOR
DTC C1593/53 Actuator Standard Position Malfunction
DESCRIPTION
If the steering control ECU detects a steering actuator standard position error, it will store DTC C1593/53.
DTC DETECTING CONDITION CHART
DTC No.

C1593/53

DTC Detecting Condition

Trouble Area

The steering control ECU detects a steering actuator standard

position error.

Steering
actuator

1. CHECK DTC
a. Check for DTCs (See TERMINALS OF ECU ).
OK:
DTC C1593/53 is not output.
NG : REPLACE STEERING ACTUATOR
OK : END
DTC C1595/55 Lost Communication With Steering Angle Sensor Module; DTC C15C4/74 Steering Angle
Signal (Test Mode DTC)
DESCRIPTION
Signal transmission between the steering control ECU and steering angle sensor is performed via serial
communication.
If an error occurs between them in serial communication, the ECU will store DTC C1595/55.
DTC DETECTING CONDITION CHART
DTC No.

DTC Detecting Condition

Trouble Area
Steering angle
sensor

C1595/55

The steering control ECU detects an error in serial

communication between the ECU and steering angle sensor.

Wire harness and

connector
Steering control

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ECU

WIRING DIAGRAM
Fig 31: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK STEERING ANGLE SENSOR

a. Check that a steering angle sensor with the specified part number is installed.
Standard:
A steering angle sensor with the specified part number (89245-30070) is installed.
NG : REPLACE STEERING ANGLE SENSOR
OK : GO TO NEXT STEP
2. CHECK WIRE HARNESS
a. Turn the engine switch off.
b. Disconnect the connectors from the steering control ECU and the steering angle sensor.
c. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

K70-10 (SS1-) - K19-7 (SS1-)

Below 1

K70-19 (SS1+) - K19-8 (SS1+)

Below 1

K70-19 (SS1+) - Body ground

10 k or higher

K70-10 (SS1-) - Body ground

10 k or higher

K70-19 (SS1+) - K70-10 (SS1-)

1 k or higher

NG : REPAIR OR REPLACE WIRE HARNESS

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Fig 32: Identifying K70 And K19 Connectors From Steering Control ECU And Steering Angle Sensor

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
3. CHECK STEERING ANGLE SENSOR
a. Connect the connector to the steering angle sensor.
b. Adjust the shift lever to neutral.
c. Jack up the vehicle.
d. Turn the engine switch on (IG).
e. Check the signal waveform according to the condition in the table below.
Voltage
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

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Condition

Specified condition

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K70-19 (SS1+) K70-10 (SS1-)

Engine switch on (IG), rotate

steering wheel slowly

Pulse generation (0
--> 5 V)

HINT:
The output voltage should fluctuate up and down similarly to the diagram on the left when the
wheel is turned slowly.
NG : REPLACE STEERING ANGLE SENSOR
Fig 33: Connecting Connector To Steering Angle Sensor

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : REPLACE STEERING CONTROL ECU

DTC C1597/57 Lost Communication Between VGRS And EPS
DESCRIPTION
The steering control ECU receives signals from the power steering ECU via local CAN communication. If the
steering control ECU cannot receive signals from the power steering ECU correctly via local CAN communication, it
will store DTC C1597/57.

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DTC DETECTING CONDITION CHART

DTC No.

C1597/57

DTC Detecting Condition

The steering control ECU detects a reception error of

signals from the power steering ECU via local CAN
communication.

Trouble Area
CAN communication
system (Local CAN)
Power steering ECU
Steering control ECU

WIRING DIAGRAM
Fig 34: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK WIRE HARNESS

a. Disconnect the connectors from the steering control ECU and the power steering ECU.
b. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

A40-4 (CAN+) - A23-1 (CAN+)

Below 1

A40-9 (CAN-) - A23-8 (CAN-)

Below 1

A40-4 (CAN+) - A40-9 (CAN-)

10 k or higher

NG : REPAIR OR REPLACE WIRE HARNESS

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Fig 35: Identifying Connectors From Steering Control ECU And Power Steering ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
2. REPLACE POWER STEERING ECU
a. Replace the power steering ECU.
b. Connect the connectors to the steering control ECU and the power steering ECU.
c. Check for DTCs in the steering control ECU (See TERMINALS OF ECU ).
OK:
DTC C1597/57 is not output.
NG : REPLACE STEERING CONTROL ECU
OK : END
DTC C15A1/61 Actuator Malfunction
DESCRIPTION

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The steering control ECU drives the actuator while the steering wheel is turned to set the gear ratio. It detects the
current flowing into the actuator motor driving circuit.
If the steering control ECU detects excessive current, it will store this DTC C15A1/61, turn on the master warning
light, and stop VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.

DTC Detecting Condition

Trouble Area
Wire harness and
connector

C15A1/61

Excessive current (exceeding the estimated amount) flows

due to a malfunction in the motor drive circuit.

Steering actuator
Steering control
ECU

WIRING DIAGRAM
Fig 36: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:
When DTC C15A2/62 is output, a short circuit inside the steering actuator or inside the steering control ECU is
suspected.
1. CHECK WIRE HARNESS
a. Turn the engine switch off.
b. Disconnect the connectors from the steering control ECU and the steering actuator.
c. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART

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Tester connection

Specified condition

K69-1 (BMV) - K69-2 (BMU)

10 k or higher

K69-1 (BMV) - K69-3 (BMW)

10 k or higher

K69-2 (BMU) - K69-3 (BMW)

10 k or higher

K69-1 (BMV) - Body ground

10 k or higher

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K69-2 (BMU) - Body ground

10 k or higher

K69-3 (BMW) - Body ground

10 k or higher

Fig 37: Identifying K69 Connector From Steering Control ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG : REPAIR OR REPLACE WIRE HARNESS

OK : GO TO NEXT STEP
2. CHECK STEERING ACTUATOR
a. Connect the connector to the steering actuator.
b. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

K69-1 (BMV) - Body ground

10 k or higher

K69-2 (BMU) - Body ground

10 k or higher

K69-3 (BMW) - Body ground

10 k or higher

NG : REPLACE STEERING ACTUATOR

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Fig 38: Connecting Connector To Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : REPLACE STEERING CONTROL ECU

DTC C15A2/62 Actuator Malfunction; DTC C15A6/62 Actuator Malfunction
DESCRIPTION
The steering control ECU drives the actuator based on steering angle sensor signals and vehicle speed signals.
If the steering control ECU detects excessive current flowing into the steering actuator, or an internal malfunction, it
will turn on the master warning light, store DTC C15A2/62, and stop VGRS operation. If the steering control ECU
detects a malfunction in the pre-driver circuit, it will turn the master warning light on, store DTC C15A6/62, and stop
VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.

DTC Detecting Condition

Trouble Area
Wire harness and
connector

C15A2/62

The VGRS system detects a malfunction in the motor

drive circuit.

Power source circuit

Steering actuator
Steering control ECU

Power source circuit

C15A6/62

The actual motor current value greatly differs from the

estimated value.

Wire harness and

connector
Steering actuator
Steering control ECU

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WIRING DIAGRAM
Fig 39: Actuator Malfunction - Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:
The actuator only can be checked in this procedure. If it is normal, the steering control ECU is faulty.
1. CHECK WIRE HARNESS (POWER SOURCE CIRCUIT)
a. Turn the engine switch off.
b. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

A40-7 (PGND) - Body ground

Below 1

c. Turn the engine switch on (IG).

d. Measure the voltage according to the value(s) in the table below.
Voltage
TESTER CONNECTION SPECIFIED CONDITION CHART

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Tester connection

Specified condition

A40-8 (PIG) - Body ground

10 to 14 V

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Fig 40: Identifying Wire Harness (Power Source Circuit)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

NG : REPAIR OR REPLACE WIRE HARNESS

OK : GO TO NEXT STEP
2. CHECK WIRE HARNESS
a. Turn the engine switch off.
b. Disconnect the connectors from the steering control ECU and the steering actuator.
c. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

K69-1 (BMV) - K69-2 (BMU)

10 k or higher

K69-1 (BMV) - K69-3 (BMW)

10 k or higher

K69-2 (BMU) - K69-3 (BMW)

10 k or higher

K69-1 (BMV) - K26-5 (BMV+)

Below 1

K69-2 (BMU) - K26-4 (BMU+)

Below 1

K69-3 (BMW) - K26-13 (BMW+)

Below 1

K69-1 (BMV) - Body ground

10 k or higher

K69-2 (BMU) - Body ground

10 k or higher

K69-3 (BMW) - Body ground

10 k or higher

NG : REPAIR OR REPLACE WIRE HARNESS

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Fig 41: Identifying Connectors From Steering Control ECU And Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
3. CHECK STEERING ACTUATOR
a. Connect the connector to the steering actuator.
b. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART

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Tester connection

Specified condition

K69-1 (BMV) - K69-2 (BMU)

Below 1

K69-1 (BMV) - K69-3 (BMW)

Below 1

K69-2 (BMU) - K69-3 (BMW)

Below 1

K69-1 (BMV) - Body ground

10 k or higher

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K69-2 (BMU) - Body ground

10 k or higher

K69-3 (BMW) - Body ground

10 k or higher

NG : REPLACE STEERING ACTUATOR

Fig 42: Connecting Connector To Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
4. CHECK DTC
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and turn the intelligent tester on.
c. Check for DTCs (See TERMINALS OF ECU ).
OK:
DTC C15A1/61 is not output.
NG : REPLACE STEERING ACTUATOR
OK : REPLACE STEERING CONTROL ECU
DTC C15A3/63 Actuator Malfunction; DTC C15C5/75 Motor Revolution Angle Signal (Test Mode DTC)
DESCRIPTION
The steering actuator drives the internal motor using the current output from the steering control ECU to change the
relative angle between tire angle and steering wheel angle.
The rotation angle sensor in the steering actuator detects the motor rotation angle and outputs this information to
the steering control ECU.
If the steering control ECU detects a malfunction in the rotation angle sensor circuit, it will store DTC C15A3/63.
DTC DETECTING CONDITION CHART

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DTC No.

C15A3/63

DTC Detecting Condition

The steering control ECU detects a malfunction in the

rotation angle sensor circuit.

Trouble Area
Wire harness and
connector
Steering actuator
Steering control ECU

WIRING DIAGRAM
Fig 43: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK WIRE HARNESS

a. Turn the engine switch off.
b. Disconnect the connectors from the steering control ECU and the steering actuator.
c. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART

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Tester connection

Specified condition

K70-4 (S1) - K26-5 (S1+)

Below 1

K70-6 (RV) - K26-1 (RV+)

Below 1

K70-14 (S2) - K26-9 (S2+)

Below 1

K70-15 (RG) - K26-10 (RG+)

Below 1

K70-4 (S1) - K70-6 (RV)

10 k or higher

K70-4 (S1) - K70-14 (S2)

10 k or higher

K70-4 (S1) - K70-15 (RG)

10 k or higher

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K70-6 (RV) - K70-14 (S2)

10 k or higher

K70-6 (RV) - K70-15 (RG)

10 k or higher

K70-14 (S2) - K70-15 (RG)

10 k or higher

K70-4 (S1) - Body ground

10 k or higher

K70-6 (RV) - Body ground

10 k or higher

K70-14 (S2) - Body ground

10 k or higher

K70-15 (RG) - Body ground

10 k or higher

NG : REPAIR OR REPLACE WIRE HARNESS

Fig 44: Identifying K70 And K26 Connectors From Steering Control ECU And Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
2. CHECK STEERING ACTUATOR
a. Connect the connector to the steering actuator.

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b. Measure the resistance according to the value(s) in the table below.

Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

K70-4 (S1) - K70-6 (RV)

Below 100

K70-4 (S1) - K70-14 (S2)

Below 100

K70-4 (S1) - K70-15 (RG)

Below 100

K70-6 (RV) - K70-14 (S2)

Below 100

K70-6 (RV) - K70-15 (RG)

Below 100

K70-14 (S2) - K70-15 (RG)

Below 100

K70-4 (S1) - Body ground

10 k or higher

K70-6 (RV) - Body ground

10 k or higher

K70-14 (S2) - Body ground

10 k or higher

K70-15 (RG) - Body ground

10 k or higher

NG : REPLACE STEERING ACTUATOR

Fig 45: Connecting K70 Connector To Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : REPLACE STEERING CONTROL ECU

DTC C15A4/64 Actuator Malfunction; DTC C15A9/66 Lock Holder Deviation Detection; DTC C15AA/66 Lock
Mechanism Release Incomplete; DTC C15AB/66 Lock Mechanism Insertion Malfunction
DESCRIPTION
When the VGRS system is normal, the steering actuator conducts current from the steering control ECU to the

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steering actuator solenoid to release the lock mechanism, enabling motor operation. The steering actuator does not
operate under either of the following conditions:
The engine is off.
The motor in the actuator is locked by the lock mechanism to prevent rotation. (Fail-safe function)
The system is being protected from overheating. (Fail-safe function)
If the steering control ECU detects a malfunction in the steering actuator lock mechanism or a motor rotation angle
error, it will store these DTCs.
DTC DETECTING CONDITION CHART
DTC No.

DTC Detecting Condition

Trouble Area

C15A4/64

The steering control ECU detects that the difference between the
actuator target angle and the actuator position is approximately 30
or more for 1 second.

Steering
actuator

C15A9/66

The steering control ECU detects that the lock pin is not aligned
with the lock holder correctly.

Steering
actuator

C15AA/66

The steering control ECU cannot operate because the actuator lock
cannot be released.

Steering
actuator

C15AB/66

The steering control ECU detects that the lock pin cannot be
inserted into the lock holder.

Steering
actuator

1. REPLACE STEERING ACTUATOR

NEXT
END
DTC C15A5/65 Actuator Malfunction
DESCRIPTION
If the steering control ECU detects a malfunction in the lock mechanism, it will turn the master warning light on, store
the DTC C15A5/65, and stop VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.

C15A5/65

DTC Detecting Condition

The steering control ECU detects that the LG terminal

voltage is abnormal.

Trouble Area
Wire harness and
connector
Steering actuator
Steering control ECU

WIRING DIAGRAM

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Fig 46: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK WIRE HARNESS

a. Turn the engine switch off.
b. Disconnect the connectors from the steering control ECU and the steering actuator.
c. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

K70-3 (LV) - K26-7 (LV+)

Below 1

K70-12 (LG) - K26-16 (LG+)

Below 1

K70-3 (LV) - Body ground

10 k or higher

K70-12 (LG) - Body ground

10 k or higher

d. Turn the engine switch on (IG).

e. Measure the voltage according to the value(s) in the table below.
Voltage
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

K70-3 (LV) - Body ground

Below 1 V

K70-12 (LG) - Body ground

Below 1 V

NG : REPAIR OR REPLACE WIRE HARNESS

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Fig 47: Identifying K70 And K26 Connectors From Steering Control ECU And Steering Actuator

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
2. CHECK STEERING ACTUATOR
a. Turn the engine switch off.
b. Connect the connector to the steering control ECU.
c. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART

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Tester connection

Specified condition

K26-7 (LV+) - K26-16 (LG+)

10 to 100

K26-7 (LV+) - Body ground

10 k or higher

K26-16 (LG+) - Body ground

10 k or higher

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NG : REPLACE STEERING ACTUATOR

Fig 48: Connecting K26 Connector To Steering Control ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : REPLACE STEERING CONTROL ECU

DTC C15B1/71 ECU Malfunction; DTC C15B2/72 ECU Malfunction; DTC C15B3/73 ECU Malfunction
DESCRIPTION
If the steering control ECU detects an internal malfunction, it will turn the master warning light on, store these DTCs,
and stop VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.

DTC Detecting Condition

Trouble Area

C15B1/71

The steering control ECU detects an internal malfunction.

Steering control
ECU

C15B2/72

The steering control ECU detects an internal malfunction.

Steering control
ECU

C15B3/73

The steering control ECU detects an internal temperature

error.

Steering control
ECU

1. REPLACE STEERING CONTROL ECU

NEXT
END
DTC C15B4/71 ECU Malfunction

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DESCRIPTION
If the steering control ECU detects an internal malfunction, it will turn the master warning light on, store DTCs
C15B4/71, and stop VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.
C15B4/71

DTC Detecting Condition

The steering control ECU detects an internal malfunction.

Trouble Area
Steering control ECU

1. CHECK MASTER WARNING LIGHT

a. Check the conditions under which the master warning light comes on.
Result:
The engine stalled, battery voltage is too low, or the steering control ECU connector is
disconnected.
NG : REPLACE STEERING CONTROL ECU
OK : GO TO NEXT STEP
2. CLEAR DTC
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and turn the intelligent tester on.
c. Clear the DTCs (See TERMINALS OF ECU ).
NEXT
3. PERFORM VGRS SYSTEM CALIBRATION
a. Perform VGRS system calibration (See INITIALIZATION ).
NEXT
4. CHECK DTC
a. Turn the engine switch on (IG).
b. Check for DTCs (See TERMINALS OF ECU ).
OK:
DTC is not output.
NG : REPLACE STEERING CONTROL ECU
OK : END
DTC C15C1/74 Steering Angle Sensor Malfunction; DTC C15C2/74 Steering Angle Sensor B+ Malfunction
DESCRIPTION
The steering control ECU detects a steering angle sensor malfunction by receiving an error signal from the steering
angle sensor via CAN communication. If the steering control ECU detects this error signal, it will turn the master
warning light on, store these DTCs, and stop VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.

C15C1/74

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DTC Detecting Condition

The steering control ECU receives a steering angle sensor
malfunction signal via CAN communication.

Trouble Area
Steering angle
sensor

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Steering angle
sensor
Steering
control ECU

Steering angle
sensor
C15C2/74

The steering control ECU receives a B+ open circuit signal from

the steering angle sensor via CAN communication.

Steering angle
sensor
Steering
control ECU

WIRING DIAGRAM
Fig 49: Wiring Diagram (1 Of 2)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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Fig 50: Wiring Diagram (2 Of 2)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK DTC
a. Check for DTCs in the skid control ECU (See DATA LIST / ACTIVE TEST ).
OK:
DTC is not output.
NG : REPAIR CIRCUIT INDICATED BY DTC OUTPUT
OK : GO TO NEXT STEP
2. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

B : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

A : REPLACE STEERING CONTROL ECU
DTC C15C3/75 Brake System Control Module Malfunction
DESCRIPTION
The steering control ECU detects a vehicle speed error by receiving an error signal from the skid control ECU via
CAN communication.
If the steering control ECU detects this error signal, it will turn the master warning light on, store this DTC, and stop
VGRS operation.
DTC DETECTING CONDITION CHART

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DTC No.

DTC Detecting Condition

Trouble Area
Skid control ECU

C15C3/75

The steering control ECU receives a vehicle speed error

signal via CAN communication.

CAN communication
system
Steering control ECU

1. CHECK DTC
a. Check for DTCs in the skid control ECU (See DATA LIST / ACTIVE TEST ).
OK:
DTC is not output.
NG : REPAIR CIRCUIT INDICATED BY DTC OUTPUT
OK : GO TO NEXT STEP
2. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

NG : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

OK : REPLACE STEERING CONTROL ECU
DTC C15C6/77 IG Power Supply Voltage Malfunction
DESCRIPTION
The steering control ECU monitors IG power supply voltage.
If the steering control ECU detects a malfunction, it will turn on the master warning light, store DTC C15C6/77, and
stop VGRS operation.
DTC DETECTING CONDITION CHART
DTC No.

DTC Detecting Condition

Trouble Area
ECU-IG LH
fuse

C15C6/77

The steering control ECU detects that the battery voltage is

normal and the IG terminal voltage is less than 4 V for 6
seconds.

IG circuit
Charging
system
Steering
control ECU

WIRING DIAGRAM

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Fig 51: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

CAUTION: The fault may be intermittent. Check

harnesses and connectors thoroughly and retest.
1. CHECK STEERING CONTROL ECU
a. Record and clear the DTCs (See TERMINALS OF ECU ).
b. Start the engine.
c. Measure the voltage according to the value(s) in the table below.
Voltage
TESTER CONNECTION SPECIFIED CONDITION CHART

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Tester connection

Specified condition

Proceed to

A40-3 (IG) - A40-7 (PGND)

9 to 16 V

A40-3 (IG) - A40-7 (PGND)

Below 9 V

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A40-3 (IG) - A40-7 (PGND)

Above 16 V

B : CHECK OR REPAIR HARNESS AND FUSE

C : CHECK AND REPAIR CHARGING SYSTEM
Fig 52: Identifying Steering Control ECU Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

A : GO TO NEXT STEP
2. CHECK DTC
a. Turn the engine switch off.
b. Connect the intelligent tester to the DLC3.
c. Turn the engine switch on (IG) and turn the intelligent tester on.
d. Check for DTCs (See TERMINALS OF ECU ).
OK:
DTC C15C6/77 is not output.
NG : REPLACE STEERING CONTROL ECU
OK : END
DTC C15C7/78 DC Motor Power Source Voltage Malfunction; DTC C15C8/79 Power Supply Relay Failure
DESCRIPTION
The steering control ECU monitors PIG (motor power source voltage) and detects a malfunction in the power supply
relay (located inside the steering control ECU).
If the steering control ECU detects a malfunction, it will turn on the master warning light, store these DTCs, and stop
VGRS operation.
DTC DETECTING CONDITION CHART

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DTC No.

DTC Detecting Condition

Trouble Area
VGRS fuse

C15C7/78

The steering control ECU detects that the IG terminal voltage is

between 9 and 16 V, and the PIG terminal voltage is less than
7 V or more than 18.5 V for 2.4 seconds.

Wire harness
and connector
Power source
circuit
Steering control
ECU

VGRS fuse
C15C8/79

The steering control ECU detects a malfunction in the power

source relay or an open circuit.

Wire harness
and connector
Steering control
ECU

WIRING DIAGRAM

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Fig 53: Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

CAUTION: The fault may be intermittent. Check

harnesses and connectors thoroughly and retest.
1. CHECK WIRE HARNESS (PGD2 - Body ground)
a. Turn the engine switch off.
b. Disconnect the negative (-) terminal cable from the battery.
c. Disconnect the connector from the steering control ECU.
d. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

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Condition

Specified condition

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A40-7 (PGND) - Body ground

Always

Below 1

NG : REPAIR OR REPLACE WIRE HARNESS

Fig 54: Identifying A40 Connector From Steering Control ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : GO TO NEXT STEP
2. CHECK STEERING CONTROL ECU
a. Connect the connector to the steering control ECU.
b. Connect the negative (-) terminal cable to the battery.
c. Record and clear the DTCs (See TERMINALS OF ECU ).
d. Start the engine.
e. Measure the voltage according to the value(s) in the table below.
Voltage
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Specified condition

Proceed to

A40-8 (PIG) - A40-7 (PGND)

9 to 16 V

A40-8 (PIG) - A40-7 (PGND)

Below 9 V

A40-8 (PIG) - A40-7 (PGND)

Above 16 V

B : CHECK OR REPAIR HARNESS AND FUSE

C : CHECK OR REPAIR CHARGING SYSTEM

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Fig 55: Connecting A40 Connector To Steering Control ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

A : GO TO NEXT STEP
3. CHECK DTC
a. Turn the engine switch off.
b. Connect the intelligent tester to the DLC3.
c. Turn the engine switch on (IG) and turn the intelligent tester on.
d. Check for DTCs (See TERMINALS OF ECU ).
OK:
Neither DTC C15C7/78 nor C15C8/79 is output.
NG : REPLACE STEERING CONTROL ECU
OK : END
DTC U0100/56 Lost Communication With ECM / PCM "A"
DESCRIPTION
The steering control ECU receives signals from the ECM (engine ECU) via CAN communication. If the steering
control ECU detects an error in reception, it will output this DTC.
DTC DETECTING CONDITION CHART
DTC No.

U0100/56

DTC Detecting Condition

The steering control ECU detects an error in reception

(from ECM) in CAN communication.

Trouble Area
CAN communication
system
ECM

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WIRING DIAGRAM
Fig 56: Lost Communication With ECM / PCM Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

B : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

A : REPLACE ECM
DTC U0122/56 Lost Communication With Vehicle Dynamics Control Module
DESCRIPTION
The steering control ECU receives signals from the skid control ECU via CAN communication. If the steering control
ECU detests an error in reception, it will output this DTC.
DTC DETECTING CONDITION CHART
DTC No.

U0122/56

DTC Detecting Condition

The steering control ECU detects an error in reception

(from skid control ECU) in CAN communication.

Trouble Area
CAN communication
system
Skid control ECU

WIRING DIAGRAM

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Fig 57: Lost Communication With Vehicle Dynamics Control Module Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

B : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

A : REPLACE SKID CONTROL ECU
DTC U0123/56 Lost Communication With Yaw Rate (Deceleration) Sensor Module
DESCRIPTION
The steering control ECU receives signals from the yaw rate (deceleration) sensor via CAN communication.
If the steering control ECU detects an error in reception, it will output this DTC.
DTC DETECTING CONDITION CHART
DTC No.

U0123/56

DTC Detecting Condition

The steering control ECU detects an error in reception

(from yaw rate (deceleration) sensor) in CAN
communication.

Trouble Area
CAN communication
system
Yaw rate
(deceleration) sensor

WIRING DIAGRAM

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Fig 58: Lost Communication With Yaw Rate (Deceleration) Sensor Module Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

B : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

A : REPLACE YAW RATE (DECELERATION) SENSOR
DTC U0126/56 Lost Communication With Steering Angle Sensor Module
DESCRIPTION
The steering control ECU receives signals from the steering angle sensor via CAN communication. If the steering
control ECU detects an error in reception, it will output this DTC.
DTC DETECTING CONDITION CHART
DTC No.

U0126/56

DTC Detecting Condition

The steering control ECU detects an error in reception

(from steering angle sensor) in CAN communication.

Trouble Area
CAN communication
system
Steering angle
sensor

WIRING DIAGRAM

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Fig 59: Lost Communication With Steering Angle Sensor Module Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

B : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

A : REPLACE STEERING ANGLE SENSOR
DTC U0131/56 Lost Communication With Power Steering Control Module
DESCRIPTION
The steering control ECU receives signals from the power steering ECU via CAN communication. If the steering
control ECU detects an error in reception, it will output this DTC.
DTC DETECTING CONDITION CHART
DTC No.

U0123/56

DTC Detecting Condition

The steering control ECU detects an error in reception

(from power steering ECU) in CAN communication.

Trouble Area
CAN communication
system
Power steering ECU

WIRING DIAGRAM

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Fig 60: Lost Communication With Power Steering Control Module Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

1. CHECK DTC
a. Check for DTCs in the CAN communication system (See GATEWAY ECU COMMUNICATION
STOP MODE ).
Result
RESULT SPECIFICATION
Result

Proceed to

DTC is not output.

DTC is output.

B : REPAIR CIRCUIT INDICATED BY DTC OUTPUT

A : REPLACE POWER STEERING ECU
Steering Wheel Is Off-center Or Deviates From Neutral Position
This problem may be caused by a malfunction in the ECB or EPS system. Make sure that no DTC is output for the
skid control ECU, power steering ECU, or steering control ECU before proceeding with the following procedures.
If a DTC is output for any of these ECUs, first troubleshoot it and then proceed.
1. CHECK DRIVE VEHICLE
a. Drive the vehicle straight at 35 km/h or more for 5 seconds or more.
b. Turn the steering wheel slowly from left and right several times, and then check if the steering
wheel is centered.
Result
RESULT SPECIFICATION
Result

Proceed to

The steering wheel is centered.

The steering wheel is off-center.

HINT:
If turning the steering wheel quickly while driving at low speeds, the steering angle may differ
between left and right, or the steering wheel may become off-center. However, this is not a
malfunction.

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A : VGRS SYSTEM IS NORMAL

B : GO TO NEXT STEP
2. CHECK TIRE SIZE
a. Check all the tires.
Result
RESULT SPECIFICATION
Result

Proceed to

All tire sizes are correct and tire pressures are normal.

The size of any of the tires is incorrect.

All tire sizes are correct, but tire pressures are incorrect.

B : REPLACE WITH SPECIFIED SIZE TIRES

C : ADJUST TIRE AIR PRESSURE TO SPECIFIED VALUE
A : GO TO NEXT STEP
3. CHECK WHEEL ALIGNMENT
a. Check wheel alignment (See ADJUSTMENT for front, ADJUSTMENT for rear).
OK:
The wheel alignment is normal.
HINT:
Adjust the tie-rod ends within the specified values so that the tire angles are the same between
left and right when the steering wheel is turned from lock to lock.
NG : PERFORM WHEEL ALIGNMENT ADJUSTMENT
OK : PERFORM STEERING ANGLE ADJUSTMENT AND VGRS SYSTEM CALIBRATION
VGRS System Stops Or Does Not Operate
HINT:
This problem may be caused by a malfunction in the ECB or EPS system.
Make sure that no DTC is output for the skid control ECU, power steering ECU, or steering control ECU before
proceeding with the following procedures.
If a DTC is output for any of these ECUs, first troubleshoot it and then proceed.
1. READ VALUE OF INTELLIGENT TESTER
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG) and intelligent tester on.
c. Select the DATA LIST mode on the intelligent tester.
ITEM NORMAL CONDITION CHART
Item
MTR
OVERHEAT

Measurement Item / Range (Display)

Record of continuous overheat preventive control /
Rec or Unrec

Normal
Condition
Rec or Unrec

Result:

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A: "Rec" (Record motor overheating)

B: "Unrec" (No record of motor overheating)
HINT:
If "Rec" is displayed, reset the setting to "Unrec". Refer to DATA LIST .
B : Go to step 3
A : GO TO NEXT STEP
2. CHECK HEAT PROTECTION FUNCTION FOR STEERING ACTUATOR
a. Turn the engine switch on (IG) and wait for 30 minutes until the steering actuator cools down.
b. Start the engine and slowly turn the steering wheel from lock to lock (approximately 90/sec) 3
times.
HINT:
If turning the steering wheel quickly while driving at low speeds, the steering angle may differ
between left and right, or the steering wheel may become off-center. However, this is not a
malfunction.
c. Check the number of turns from lock to lock.
Result:
A: 2.7 turns
B: 3.2 turns
B : Go to step 3
A : VGRS SYSTEM IS NORMAL
3. CHECK STEERING EFFORT
a. Start the engine.
b. Turn the steering wheel.
c. Check the steering effort.
OK:
Below 6.5 N*m (66 kgf*cm, 57 in.*lbf)
HINT:
After completing the inspection or repair, attempt to simulate the problem and then perform step
1 again to reconfirm that the problem does not occur.
NG : GO TO POWER STEERING SYSTEM
OK : GO TO NEXT STEP
4. CHECK STEERING ACTUATOR
a. Check for an abnormal noise or vibration in the steering actuator.
OK:
Neither an abnormal noise or vibration occurs.
NG : GO TO STEERING WHEEL VIBRATES OR ABNORMAL NOISE IS HEARD FROM STEERING
WHEEL
OK : GO TO NEXT STEP
5. CHECK WIRE HARNESS

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a. Turn the engine switch on (IG).

b. Measure the voltage and resistance according to the value(s) in the table below.
Voltage
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Condition

Specified condition

A40-3 (IG) - Body ground

Engine switch on (IG)

10 to 14 V

A40-8 (PIG) - Body ground

Engine switch on (IG)

10 to 14 V

c. Turn the engine switch off.

d. Measure the resistance according to the value(s) in the table below.
Resistance
TESTER CONNECTION SPECIFIED CONDITION CHART
Tester connection

Condition

Specified condition

A40-7 (PGND) - Body ground

Always

Below 1

NG : REPAIR OR REPLACE WIRE HARNESS

Fig 61: Identifying Wire Harness

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

OK : REPLACE STEERING CONTROL ECU

Steering Angle Differs Between Left And Right
HINT:
Check that the steering wheel is centered.

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After checking that no DTC is output for the VGRS system, perform the following procedure.
1. CHECK STEERING WHEEL POSITION
a. Turn the steering wheel from lock to lock at a speed of approximately 90/sec Check if the
steering wheel angles between left and right.
OK:
The steering wheel is centered.
HINT:
If turning the steering wheel quickly while driving at low speeds, the steering angle may differ
between left and right, or the steering wheel may become off-center. However, this is not a
malfunction.
OK : VGRS SYSTEM IS NORMAL
NG : GO TO NEXT STEP
2. CHECK STEERING EFFORT
a. Start the engine.
b. Turn the steering wheel.
c. Check the steering effort.
OK:
Below 6.5 N*m (66 kgf*cm, 57 in.*lbf)
HINT:
After completing the inspection or repair, attempt to simulate the problem and then perform step
1 again to reconfirm that the problem does not occur.
NG : GO TO POWER STEERING SYSTEM
OK : GO TO NEXT STEP
3. CHECK WHEEL ALIGNMENT
a. Check wheel alignment (See ADJUSTMENT for front, ADJUSTMENT for rear).
OK:
The wheel alignment is normal.
HINT:
Adjust the tie-rod ends within the specified values so that the tire angles are the same between
left and right when the steering wheel is turned from lock to lock.
NG : PERFORM WHEEL ALIGNMENT ADJUSTMENT
OK : PERFORM REINSTALL STEERING GEAR NEUTRAL POSITION AND STEERING COLUMN
NEUTRAL POSITION
Steering Wheel Vibrates Or Abnormal Noise Is Heard From Steering Wheel
HINT:
Check that no DTC is output for the VGRS system, ECB system, and ABS system.
1. CHECK STEERING WHEEL CONDITION
a. Turn the engine switch on (IG).
b. Check for abnormal noise or vibration while turning the steering wheel.

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OK:
No abnormal noise or vibration.

NOTE: DTC C15A5/65 is stored when the

engine switch is turned on (IG) with the
connector disconnected from the steering
control ECU. Clear the DTC after this check.
NG : REPLACE STEERING ACTUATOR ASSY
OK : GO TO NEXT STEP
2. REPAIR OR REPLACE POWER STEERING SYSTEM
a. Repair or replace the power steering system (See POWER STEERING SYSTEM ).
NEXT
CHECK DTC OF VGRS SYSTEM
Master Warning Light Malfunction
DESCRIPTION
If the steering control ECU detects that VGRS system has a malfunction, warning information is transmitted to the
combination meter via CAN and BEAN.
The combination meter will turn the master warning light on based on this information.
Warning information is transmitted via the following route:
Steering control ECU --> (CAN) --> Power steering ECU --> (CAN) --> Gateway ECU --> (BEAN) -->
Combination meter
Connecting terminals TC and CG of the DLC3 makes the master warning light blink and outputs DTCs.
WIRING DIAGRAM

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Fig 62: Wiring Diagram (1 Of 4)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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Fig 63: Wiring Diagram (2 Of 4)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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Fig 64: Wiring Diagram (3 Of 4)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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Fig 65: Wiring Diagram (4 Of 4)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:
Check that there is no problem in CAN and BEAN communications before performing the following procedure.
If there is any problem in these communications, first troubleshoot it and then proceed.
1. CHECK BATTERY
a. Measure the battery voltage.
OK:
11 to 14 V
NG : REPLACE BATTERY
OK : GO TO NEXT STEP
2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (COMBINATION METER)
a. Connect the intelligent tester to the DLC3.
b. Turn the engine switch on (IG).

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c. From the display on tester, perform the "Active Test".

Result
ITEM DIAGNOSTIC NOTE CHART
Item
MST WARN
INDICATOR

Test Details
Master warning
(OFF/ON)

Diagnostic Note
Confirm that the vehicle is stopped and
engine idling

NG : CHECK AND REPLACE COMBINATION METER

OK : GO TO NEXT STEP
3. CHECK POWER STEERING SYSTEM
a. Check for DTCs in the power steering system (See DTC CHECK / CLEAR ).
OK:
DTC is not output.
NG : GO TO POWER STEERING SYSTEM
OK : GO TO NEXT STEP
4. CHECK WIRE HARNESS
a. Check for an open or short circuit in the wire harnesses (CANH and CANL) of the ECM (See
ECM COMMUNICATION STOP MODE ).
OK:
The wire harnesses are normal.
NG : REPAIR OR REPLACE WIRE HARNESS
OK : REPLACE STEERING CONTROL ECU

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