Infiniti G37 Coupe. Manual - part 1253

C1652 4WAS FRONT MOTOR POWER SUPPLY

STC-63

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

NO

>> GO TO 3.

3.

4WAS FRONT CONTROL UNIT SIGNAL INSPECTION

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Check “MOTOR VOLT” item on “DATA MONITOR” of 4WAS front control unit.

Does the item on “DATA MONITOR” indicate “16 V” or more?

YES

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

STC-168, "Symptom Table"

.

NO

>> Replace 4WAS front control unit. Refer to 

STC-177, "Exploded View"

.

Special Repair Requirement

INFOID:0000000001666335

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.

• Erase the memory of the self-diagnosis results (record) after printing out or recording all the val-

ues of “DATA MONITOR”.

AFTER REPLACING 4WAS FRONT CONTROL UNIT

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

STC-28, "4WAS

FRONT ACTUATOR NEUTRAL POSITION ADJUSTMENT : Special Repair Requirement (Pattern 3)"

.

STC-64

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

C1654 4WAS FRONT ACTUATOR RELAY

C1654 4WAS FRONT ACTUATOR RELAY

Description

INFOID:0000000001666336

• It performs control inside 4WAS front control unit.
• The actuator relay turns ON when turning the ignition switch ON.
• When turning the ignition switch from ON to OFF, the actuator relay remains ON and is turned OFF after a

few minutes due to the 4WAS front control unit control.

DTC Logic

INFOID:0000000001666337

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 “C1654” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-64, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001666338

1.

4WAS FRONT MOTOR GROUND INSPECTION

1.

Turn the ignition switch OFF.

2.

Check the continuity between 4WAS front control unit harness connector and the ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace the harnesses and connectors.

2.

4WAS FRONT MOTOR POWER SUPPLY INSPECTION

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Check the voltage between 4WAS front control unit harness connectors.

Is the measurement value “9 V” or less?

YES

>>

Check the following items. Repair or replace the malfunctioning parts.

• 4WAS front control unit harness connector pin terminal and connection
• 40A fusible link (#I) open

DTC

Items

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

C1654

ACTUATOR RELAY

An error is detected on the main relay power supply in-
side 4WAS front control unit.

The main relay power 
supply inside 4WAS front 
control unit error is de-
tected.

4WAS front control unit

Continuity

Connector

Terminal

M41

12 – Ground

Existed

4WAS front control unit

Voltage (Approx.)

Connector

Terminal

M41

11 – 12

Battery voltage

C1654 4WAS FRONT ACTUATOR RELAY

STC-65

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

- Short among 40A fusible link (#I) connector, 4WAS front control unit harness connector No. 11

terminal and the ground

• Open between the battery and 4WAS front control unit harness connector No. 11 terminal
• Battery

NO

>> GO TO 3.

3.

4WAS FRONT CONTROL UNIT SIGNAL INSPECTION

With CONSULT-III

1.

Start the engine.

CAUTION:

Stop the vehicle.

2.

Check “MOTOR VOLT” item on “DATA MONITOR” of 4WAS front control unit.

Does the item on “DATA MONITOR” indicate “16 V” or more?

YES

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

STC-168, "Symptom Table"

.

NO

>> Replace 4WAS front control unit. Refer to 

STC-177, "Exploded View"

.

Special Repair Requirement

INFOID:0000000001666339

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.

• Erase the memory of the self-diagnosis results (record) after printing out or recording all the val-

ues of “DATA MONITOR”.

AFTER REPLACING 4WAS FRONT CONTROL UNIT

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

STC-28, "4WAS

FRONT ACTUATOR NEUTRAL POSITION ADJUSTMENT : Special Repair Requirement (Pattern 3)"

.

STC-66

< COMPONENT DIAGNOSIS >

[WITH 4WAS]

C1655 4WAS FRONT DRIVER

C1655 4WAS FRONT DRIVER

Description

INFOID:0000000001666340

• It perform control inside 4WAS front control unit. 
• The power supply for 4WAS front motor (3-phase motor).

DTC Logic

INFOID:0000000001666341

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 “C1655” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-66, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000001666342

1.

CHECK 4WAS FRONT MOTOR GROUND

1.

Turn the ignition switch OFF.

2.

Disconnect 4WAS front control unit harness connector.

3.

Check the continuity between 4WAS front control unit harness connector and the ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace the harnesses and connectors.

2.

PERFORM SELF-DIAGNOSIS (4WAS FRONT CONTROL UNIT)

With CONSULT-III

1.

Connect 4WAS front control unit harness connector.

2.

Perform 4WAS front control unit self-diagnosis.

Is DTC “C1622” detected?

YES

>> Check the error system.

NO

>> Replace 4WAS front control unit. Refer to 

STC-177, "Exploded View"

.

Special Repair Requirement

INFOID:0000000001666343

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

C1655

PRE-DRIVER

4WAS front motor 3-phase current error is detected.
(Current is not applied to 4WAS front motor)

4WAS front control unit or 
4WAS front motor power 
supply error is detected.

4WAS front control unit

Continuity

Connector

Terminal

M41

12 – Ground

Existed