Infiniti FX35, FX50 (S51). Manual - part 1777

C1905, C1908, C1922, C1925, C1928 RAS CONTROL UNIT

STC-49

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

2.

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

STC-

89, "Reference Value"

.

Is each data the standard value?

YES

>> Check each harness connector pin terminal for disconnection.

NO

>> Replace RAS control unit. Refer to 

STC-109, "Removal and Installation"

.

Special Repair Requirement

INFOID:0000000005549673

BEFORE REPLACING RAS CONTROL UNIT

• Record the self-diagnosis results (history).

CAUTION:

• Never erase the memory (history) of self-diagnosis results when replacing RAS 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”.

STC-50

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

C1909 RAS CONTROL UNIT

C1909 RAS CONTROL UNIT

Description

INFOID:0000000005549674

• RAS actuator and the power steering solenoid valve is controlled by each sensor signal.
• The fail-safe function stops the rear wheel angle function, when the electric components and the mechanical

components are malfunctioning.

• The protective function stops RAS system temporarily when the input signal is not inputted to RAS control

unit (When battery-power dose not work temporarily).

DTC Logic

INFOID:0000000005549675

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC REPRODUCTION PROCEDURE

With CONSULT-III

1.

Turn the ignition switch from OFF to ON.

2.

Perform “4WAS(MAIN)/RAS/HICAS” self-diagnosis.

Without CONSULT-III

1.

Start the engine.

2.

Perform the self-diagnosis. Refer to 

STC-38, "Diagnosis Description"

.

Is DTC “C1909” or “RAS warning lamp flickering pattern:11” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-50, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005549676

1.

CHECK RAS CONTROL UNIT POWER SUPPLY

1.

Turn the ignition switch OFF.

2.

Disconnect RAS control unit harness connector.

3.

Check the voltage between RAS control unit harness connector terminal and ground.

4.

Turn the ignition switch ON.

CAUTION:

Never start the engine.

5.

Check the voltage between RAS control unit harness connector terminal and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NG

>>

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

• 10A fuse (#45) open
- Short among 10A fuse (#45) connector, RAS control unit harness connector No. 27 terminal and

the ground

DTC

Display items

Malfunction detected condition

Possible cause

C1909

CONTROL UNIT
[ABNORMAL6]

Malfunction has occurred inside RAS control unit.

• RAS control unit
• Harness or connector

RAS control unit

—

Voltage (Approx.)

Connector

Terminal

B37

27 Ground

0 

V

RAS control unit

—

Voltage (Approx.)

Connector

Terminal

B37

27 Ground

Battery 

voltage

C1909 RAS CONTROL UNIT

STC-51

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

• Open between the ignition switch and RAS control unit harness connector No. 27 terminal
• Ignition switch

2.

CHECK RAS CONTROL UNIT GROUND

Check the continuity between RAS control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NG

>> Repair or replace the harnesses and connectors.

3.

PERFORM SELF-DIAGNOSIS

With CONSULT-III

1.

Connect RAS control unit harness connector.

2.

Turn the ignition switch from OFF to ON.

3.

Perform “4WAS(MAIN)/RAS/HICAS” self-diagnosis.

Without CONSULT-III

1.

Connect RAS control unit harness connector.

2.

Start the engine.

3.

Perform the self-diagnosis. Refer to 

STC-38, "Diagnosis Description"

.

Is DTC “C1909” or “RAS warning lamp flickering pattern:11” detected?

YES

>> Replace RAS control unit. Refer to 

STC-109, "Removal and Installation"

.

NO

>> GO TO 4.

4.

CHECK INFORMATION

With CONSULT-III

1.

Select “DATA MONITOR” of “4WAS(MAIN)/RAS/HICAS”.

2.

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

STC-

89, "Reference Value"

.

Is each data the standard value?

YES

>> Check each harness connector pin terminal for disconnection.

NO

>> Replace RAS control unit. Refer to 

STC-109, "Removal and Installation"

.

Special Repair Requirement

INFOID:0000000005549677

BEFORE REPLACING RAS CONTROL UNIT

• Record the self-diagnosis results (history).

CAUTION:

• Never erase the memory (history) of self-diagnosis results when replacing RAS 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”.

RAS control unit

—

Continuity

Connector

Terminal

B37

34 Ground

Existed

STC-52

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

C1911, C1912 RAS MOTOR POWER SUPPLY

C1911, C1912 RAS MOTOR POWER SUPPLY

Description

INFOID:0000000005549678

The power supply for RAS motor.

DTC Logic

INFOID:0000000005549679

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC REPRODUCTION PROCEDURE

With CONSULT-III

1.

Turn the ignition switch from OFF to ON.

2.

Perform “4WAS(MAIN)/RAS/HICAS” self-diagnosis.

Without CONSULT-III

1.

Start the engine.

2.

Perform the self-diagnosis. Refer to 

STC-38, "Diagnosis Description"

.

Is DTC “C1911”, “C1912” or “RAS warning lamp flickering pattern:12” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-52, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005549680

1.

CHECK RAS CONTROL UNIT POWER SUPPLY

1.

Turn the ignition switch OFF.

2.

Disconnect RAS control unit harness connector.

3.

Check the voltage between RAS control unit harness connector and ground.

4.

Turn the ignition switch ON.

CAUTION:

Never start the engine.

5.

Check the voltage between RAS control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NG

>>

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

• 10A fuse (#45) open
- Short among 10A fuse (#45) connector, RAS control unit harness connector No. 27 terminal and

the ground

DTC

Display items

Malfunction detected condition

Possible cause

C1911

MOTOR VOLTAGE
[LOW VOLTAGE]

RAS motor voltage error is detected.
(RAS motor voltage is low.)

• RAS motor relay
• Harness or connector
• RAS control unit

C1912

MOTOR VOLTAGE
[BAD OBSTRCT]

RAS motor voltage error is detected.
(Voltage is applied to RAS motor when RAS control unit 
output is “OFF”.)

• RAS motor relay
• Harness or connector
• RAS control unit

RAS control unit

—

Voltage (Approx.)

Connector

Terminal

B37

27 Ground

0 

V

RAS control unit

—

Voltage (Approx.)

Connector

Terminal

B37

27 Ground

Battery 

voltage