Infiniti FX35, FX50 (S51). Manual - part 1775

DIAGNOSIS SYSTEM (RAS CONTROL UNIT)

STC-41

< SYSTEM DESCRIPTION >

[WITH REAR ACTIVE STEER]

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A

B

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RR ST ANG-SUB

2.4 V

Approx. 4.4 V

Approx. 0.4 V

MOTOR CURRENT

No output (Approx. 0 A)

Output (change)

Monitor item

Active test “ON”

STC-42

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

C1900, C1901, C1906, C1907, C1927, C1933 RAS CONTROL UNIT

DTC/CIRCUIT DIAGNOSIS

C1900, C1901, C1906, C1907, C1927, C1933 RAS CONTROL UNIT

Description

INFOID:0000000005549661

• 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:0000000005549662

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 “C1900”,  “C1901”,  “C1906”,  “C1907”,  “C1927”,  “C1933” or “RAS warning lamp flickering pattern:11”
detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-42, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005549663

1.

PERFORM SELF-DIAGNOSIS

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 “C1900”,  “C1901”,  “C1906”,  “C1907”,  “C1927”,  “C1933” or “RAS warning lamp flickering pattern:11”
detected?

YES

>> Replace RAS control unit. Refer to 

STC-109, "Removal and Installation"

.

NO

>> GO TO 2.

DTC

Display Items

Malfunction detected condition

Possible cause

C1900

CONTROL UNIT
[ABNORMAL1]

Malfunction has occurred inside RAS control unit.

• RAS control unit
• Harness or connector

C1901

CONTROL UNIT
[ABNORMAL2]

Malfunction has occurred inside RAS control unit.

• RAS control unit
• Harness or connector

C1906

CONTROL UNIT
[ABNORMAL5]

Malfunction has occurred inside RAS control unit.

• RAS control unit
• Harness or connector

C1907

CONTROL UNIT
[ABNORMAL4]

Malfunction has occurred inside RAS control unit.

• RAS control unit
• Harness or connector

C1927

CONTROL UNIT
[ABNORMAL5]

Malfunction has occurred inside RAS control unit.

• RAS control unit
• Harness or connector

C1933

CONTROL UNIT

Malfunction has occurred inside RAS control unit.

RAS control unit

C1900, C1901, C1906, C1907, C1927, C1933 RAS CONTROL UNIT

STC-43

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

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2.

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:0000000005549664

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-44

< DTC/CIRCUIT DIAGNOSIS >

[WITH REAR ACTIVE STEER]

C1902, C1903, C1904, C1910, C1913 RAS MOTOR OUTPUT

C1902, C1903, C1904, C1910, C1913 RAS MOTOR OUTPUT

Description

INFOID:0000000005549665

• RAS motor activates RAS actuator.
• Maintain the toe-stiffness of rear wheels against the road external force because the irreversible sufficiency

performance hypoid gear is used.

DTC Logic

INFOID:0000000005549666

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

DTC REPRODUCTION PROCEDURE

With CONSULT-III

1.

Perform “SELF DIAGNOSTIC MODE” item on “ACTIVE TEST” of “4WAS(MAIN)/RAS/HICAS”.

CAUTION:

Perform the active test while vehicle is stopped.

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 “C1902”, “C1903”, “C1904”, “C1910”, “C1913” or “RAS warning lamp flickering pattern:13” detected?

YES

>> Proceed to diagnosis procedure. Refer to 

STC-44, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005549667

1.

CHECK RAS MOTOR CIRCUIT

1.

Turn the ignition switch OFF.

2.

Disconnect RAS control unit harness connector.

3.

Disconnect RAS motor harness connector.

4.

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

DTC

Display items

Malfunction detected condition

Possible cause

C1902

MOTOR OUTPUT
[REV CURRENT]

RAS motor current error is detected.
(RAS motor current output direction differs.)

• RAS motor
• Harness or connector
• RAS control unit

C1903

MOTOR OUTPUT
[NO CURRENT]

RAS motor current error is detected.
(Current is inputted to RAS control unit if RAS control 
unit output is “OFF”.)

• RAS motor
• Harness or connector
• RAS control unit

C1904

MOTOR OUTPUT
[OVERCURRENT]

RAS motor current error is detected.
(RAS motor output is over current.)

• RAS motor
• Harness or connector
• RAS control unit

C1910

MOTOR OUTPUT
[MOTOR LOCK]

RAS motor inside error is detected.
(RAS motor does not move or the rear wheel angle 
sensor does not change if RAS control unit output is 14 
A or more.)

• RAS motor
• Harness or connector
• RAS control unit

C1913

MOTOR OUTPUT
[ABNORML SIG]

RAS motor current error is detected.
(RAS motor does not move or the rear wheel angle 
sensor output does not change when RAS control unit 
output is 18 A or more, and RAS motor output is low.)

• RAS motor
• Harness or connector
• RAS control unit