Infiniti G37 Coupe. Manual - part 1255

C1667 LOCK INSERTION

STC-71

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

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STC

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1.

Check the “DATA MONITOR” value of each DTC detected with the self-diagnosis function. Refer to 

STC-

142, "Reference Value"

.

2.

Perform 4WAS front control unit self-diagnosis.

Is each data the standard value?

YES

>> GO TO 1.

NO

>> Replace 4WAS front control unit. Refer to 

STC-177, "Exploded View"

.

Special Repair Requirement

INFOID:0000000001666352

AFTER REPLACING 4WAS FRONT ACTUATOR

• Perform 4WAS front actuator adjustment after replacing 4WAS front actuator. Refer to 

STC-28, "4WAS

FRONT ACTUATOR NEUTRAL POSITION ADJUSTMENT : Special Repair Requirement (Pattern 2)"

.

STC-72

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

C1668 LOCK HOLDER GAP DETECT

C1668 LOCK HOLDER GAP DETECT

Description

INFOID:0000000001666353

• Wiring connected to 4WAS front actuator is integrated with 4WAS front actuator.
• 4WAS front actuator rotates together with steering wheel.
• 4WAS front actuator mainly consists of five components. [4WAS front lock solenoid valve (lock structure),

front wheel steering angle sensor, 4WAS front motor, gear shaft, and spiral cable]

- 4WAS front lock solenoid valve (lock structure) is controlled by the 4WAS front control unit, and locks/

unlocks 4WAS front actuator.

- If a strong force (rotation direction) is applied to 4WAS front actuator, the locking mechanism (holder)

absorbs the force and locks 4WAS front actuator.

- Front wheel steering angle sensor detects a turning angle of 4WAS front motor.
- 4WAS front motor controls number of revolutions by a command value from the 4WAS front control unit.
- Gear shaft is an output axis of 4WAS front motor. (Gear shaft = 4WAS front motor revolution + steering

angle)

- Spiral cables mean the power line and signal lines of 4WAS front motor.

DTC Logic

INFOID:0000000001666354

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

RECHECK DTC

With CONSULT-III

1.

Turn the ignition switch from OFF to ON.

2.

Perform 4WAS front control unit self-diagnosis.

Is DTC “C1668” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-72, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001666355

1.

PERFORM SELF-DIAGNOSIS (4WAS FRONT CONTROL UNIT)

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Perform 4WAS front control unit self-diagnosis. Check that DTC “C1668” is detected.

CAUTION:

• Replace 4WAS front actuator when the diagnosis history remains.
• Never repair the malfunctioning part in 4WAS front actuator adjustment without replacing 4WAS

front actuator.

>> Replace 4WAS front actuator. Refer to 

STC-168, "Symptom Table"

.

Special Repair Requirement

INFOID:0000000001666356

AFTER REPLACING 4WAS FRONT ACTUATOR

• Perform 4WAS front actuator adjustment after replacing 4WAS front actuator. Refer to 

STC-28, "4WAS

FRONT ACTUATOR NEUTRAL POSITION ADJUSTMENT : Special Repair Requirement (Pattern 2)"

.

DTC

Items

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

C1668

LOCK HLD GAP DETCT

4WAS front lock solenoid valve (lock) error is detected.
(Excessive force is applied to the lock.)

The inside 4WAS front 
actuator error is detected.

C1669 INCOMPLETE LOCK RELEASE

STC-73

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

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C1669 INCOMPLETE LOCK RELEASE

Description

INFOID:0000000001666357

• Wiring connected to 4WAS front actuator is integrated with 4WAS front actuator.
• 4WAS front actuator rotates together with steering wheel.
• 4WAS front actuator mainly consists of five components. [4WAS front lock solenoid valve (lock structure),

front wheel steering angle sensor, 4WAS front motor, gear shaft, and spiral cable]

- 4WAS front lock solenoid valve (lock structure) is controlled by the 4WAS front control unit, and locks/

unlocks 4WAS front actuator.

- If a strong force (rotation direction) is applied to 4WAS front actuator, the locking mechanism (holder)

absorbs the force and locks 4WAS front actuator.

- Front wheel steering angle sensor detects a turning angle of 4WAS front motor.
- 4WAS front motor controls number of revolutions by a command value from the 4WAS front control unit.
- Gear shaft is an output axis of 4WAS front motor. (Gear shaft = 4WAS front motor revolution + steering

angle)

- Spiral cables mean the power line and signal lines of 4WAS front motor.

DTC Logic

INFOID:0000000001666358

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

RECHECK DTC

With CONSULT-III

1.

Turn the ignition switch from OFF to ON.

2.

Perform 4WAS front control unit self-diagnosis.

Is DTC “C1669” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-73, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001666359

1.

CHECK INFORMATION

• Check that any item below is applicable.
- The steering force is heavy when 4WAS warning lamp is ON.
- The power steering system error is detected (oil leakage, belt tension, steering force etc.).

Is the item applicable?

YES

>> Perform the symptom diagnosis for the steering system. Refer to 

ST-3, "NVH Troubleshooting

Chart"

.

NO

>> Replace 4WAS front actuator. Refer to 

STC-179, "Removal and Installation"

.

Special Repair Requirement

INFOID:0000000001666360

AFTER REPLACING 4WAS FRONT ACTUATOR

• Perform 4WAS front actuator adjustment after replacing 4WAS front actuator. Refer to 

STC-28, "4WAS

FRONT ACTUATOR NEUTRAL POSITION ADJUSTMENT : Special Repair Requirement (Pattern 2)"

.

DTC

Items

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

C1669

INCOMP LOCK RELEAS

4WAS front actuator error is detected.
(An error is detected in unlock condition.)

The power steering oil 
pressure or the inside 
4WAS front actuator error 
is detected.

STC-74

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

C1671 ACTUATOR ADJUSTMENT NOT PERFORMED

C1671 ACTUATOR ADJUSTMENT NOT PERFORMED

Description

INFOID:0000000001666361

• Memorize the neutral position of 4WAS front actuator in 4WAS front control unit.

DTC Logic

INFOID:0000000001666362

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

RECHECK DTC

With CONSULT-III

1.

Turn the ignition switch from OFF to ON.

2.

Perform 4WAS front control unit self-diagnosis.

Is DTC “C1671” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-74, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001666363

1.

PERFORM SELF-DIAGNOSIS (4WAS FRONT CONTROL UNIT)

With CONSULT-III

Perform 4WAS front control unit self-diagnosis.

Is any DTC other than “C1671” detected?

YES

>> Check the error system.

NO

>> GO TO 2.

2.

4WAS FRONT ACTUATOR ADJUSTMENT

With CONSULT-III

1.

Perform 4WAS front actuator adjustment. Refer to 

STC-28, "4WAS FRONT ACTUATOR NEUTRAL

POSITION ADJUSTMENT : Special Repair Requirement (Pattern 2)"

.

2.

Perform 4WAS front control unit self-diagnosis.

Is any DTC other than “C1671” detected?

YES

>> Check the error system.

NO

>> GO TO 3.

3.

PERFORM SELF-DIAGNOSIS (4WAS FRONT CONTROL UNIT)

With CONSULT-III

Perform 4WAS front control unit self-diagnosis.

Is DTC “C1671” detected?

YES

>> Replace 4WAS front control unit. Refer to 

STC-177, "Exploded View"

.

NO

>> INSPECTION END

Special Repair Requirement

INFOID:0000000001666364

BEFORE REPLACING 4WAS FRONT CONTROL UNIT

• Record the self-diagnosis results (history).

CAUTION:

• Never erase the memory (history) of self-diagnosis results when replacing 4WAS front control unit

after diagnosis.

DTC

Items

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

C1671

ACT ADJ NOT PRFRM

4WAS front actuator adjustment is not performed.

4WAS front actuator ad-
justment is not per-
formed.