Infiniti FX35, FX50 (S51). Manual - part 1765

STC-1

STEERING

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SECTION 

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CONTENTS

STEERING CONTROL SYSTEM

WITHOUT REAR ACTIVE STEER

BASIC INSPECTION  ....................................

4

DIAGNOSIS AND REPAIR WORK FLOW  .........

4

Work Flow  .................................................................

4

SYSTEM DESCRIPTION  ..............................

5

EPS SYSTEM  ......................................................

5

System Diagram ........................................................

5

System Description  ...................................................

5

Component Parts Location ........................................

7

Component Description .............................................

7

DTC/CIRCUIT DIAGNOSIS  ..........................

8

POWER SUPPLY AND GROUND CIRCUIT .......

8

Description ................................................................

8

Diagnosis Procedure .................................................

8

POWER STEERING SOLENOID VALVE  ...........

9

Description ................................................................

9

Diagnosis Procedure .................................................

9

Component Inspection  ............................................

10

ENGINE SPEED SIGNAL CIRCUIT  ...................

11

Description ..............................................................

11

Diagnosis Procedure ...............................................

11

VEHICLE SPEED SIGNAL CIRCUIT  .................

14

Description ..............................................................

14

Diagnosis Procedure ...............................................

14

ECU DIAGNOSIS INFORMATION ..............

16

POWER STEERING CONTROL UNIT  ...............

16

Reference Value  .....................................................

16

Wiring Diagram - ELECTRONICALLY CON-
TROLLED POWER STEERING SYSTEM - ............

18

Fail-Safe ..................................................................

23

SYMPTOM DIAGNOSIS  ..............................

25

UNBALANCE STEERING WHEEL TURNING 
FORCE (TORQUE VARIATION) .......................

25

Description ...............................................................

25

Diagnosis Procedure  ...............................................

25

PRECAUTION ..............................................

26

PRECAUTIONS .................................................

26

Precaution for Supplemental Restraint System 
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .................................................................

26

Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect  ...................................

26

REMOVAL AND INSTALLATION  ...............

27

POWER STEERING CONTROL UNIT ..............

27

Removal and Installation  .........................................

27

WITH REAR ACTIVE STEER

BASIC INSPECTION  ...................................

28

DIAGNOSIS AND REPAIR WORKFLOW  ........

28

Work Flow ................................................................

28

Question sheet  ........................................................

29

SYSTEM DESCRIPTION  .............................

31

RAS SYSTEM  ...................................................

31

System Diagram  ......................................................

31

System Description ..................................................

31

Component Parts Location  ......................................

33

Component Description  ...........................................

34

EPS SYSTEM ....................................................

35

System Diagram  ......................................................

35

System Description ..................................................

35

Component Parts Location  ......................................

37

Component Description  ...........................................

37

DIAGNOSIS SYSTEM (RAS CONTROL UNIT) 

...

38

STC-2

Diagnosis Description  .............................................

38

CONSULT-III Function  ...........................................

39

DTC/CIRCUIT DIAGNOSIS .........................

42

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

42

Description ..............................................................

42

DTC Logic ...............................................................

42

Diagnosis Procedure  ..............................................

42

Special Repair Requirement ...................................

43

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

44

Description ..............................................................

44

DTC Logic ...............................................................

44

Diagnosis Procedure  ..............................................

44

Component Inspection ............................................

46

Special Repair Requirement ...................................

46

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

48

Description ..............................................................

48

DTC Logic ...............................................................

48

Diagnosis Procedure  ..............................................

48

Special Repair Requirement ...................................

49

C1909 RAS CONTROL UNIT  ............................

50

Description ..............................................................

50

DTC Logic ...............................................................

50

Diagnosis Procedure  ..............................................

50

Special Repair Requirement ...................................

51

C1911, C1912 RAS MOTOR POWER SUP-
PLY ....................................................................

52

Description ..............................................................

52

DTC Logic ...............................................................

52

Diagnosis Procedure  ..............................................

52

Component Inspection ............................................

54

Special Repair Requirement ...................................

55

C1914 REAR WHEEL STEERING ANGLE 
SENSOR ............................................................

56

Description ..............................................................

56

DTC Logic ...............................................................

56

Diagnosis Procedure  ..............................................

56

Component Inspection ............................................

57

Special Repair Requirement ...................................

58

C1915, C1916 REAR WHEEL STEERING AN-
GLE SENSOR  ....................................................

59

Description ..............................................................

59

DTC Logic ...............................................................

59

Diagnosis Procedure  ..............................................

59

Component Inspection ............................................

61

Special Repair Requirement ...................................

61

C1917, C1918 REAR WHEEL STEERING AN-
GLE SENSOR  ....................................................

62

Description ..............................................................

62

DTC Logic  ...............................................................

62

Diagnosis Procedure ...............................................

62

Component Inspection  ............................................

64

Special Repair Requirement  ...................................

64

C1919 VEHICLE SPEED SIGNAL  ....................

65

Description ..............................................................

65

DTC Logic  ...............................................................

65

Diagnosis Procedure ...............................................

65

Special Repair Requirement  ...................................

66

C1920 STEERING ANGLE SENSOR  ...............

67

Description ..............................................................

67

DTC Logic  ...............................................................

67

Diagnosis Procedure ...............................................

67

Special Repair Requirement  ...................................

68

C1921 ENGINE SPEED SIGNAL  ......................

69

Description ..............................................................

69

DTC Logic  ...............................................................

69

Diagnosis Procedure ...............................................

69

Special Repair Requirement  ...................................

70

C1923 STEERING ANGLE SENSOR  ...............

71

Description ..............................................................

71

DTC Logic  ...............................................................

71

Diagnosis Procedure ...............................................

71

Special Repair Requirement  ...................................

72

C1924 STEERING ANGLE SENSOR  ...............

73

Description ..............................................................

73

DTC Logic  ...............................................................

73

Diagnosis Procedure ...............................................

73

Special Repair Requirement  ...................................

74

C1926 STEERING ANGLE SENSOR  ...............

75

Description ..............................................................

75

DTC Logic  ...............................................................

75

Diagnosis Procedure ...............................................

75

Special Repair Requirement  ...................................

76

C1929 ABS ACTUATOR AND ELECTRIC 
UNIT (CONTROL UNIT)  ....................................

77

Description ..............................................................

77

DTC Logic  ...............................................................

77

Diagnosis Procedure ...............................................

77

Special Repair Requirement  ...................................

78

U1000 CAN COMM CIRCUIT  ............................

79

Description ..............................................................

79

DTC Logic  ...............................................................

79

Diagnosis Procedure ...............................................

79

Special Repair Requirement  ...................................

79

U1010 CONTROL UNIT (CAN)  .........................

80

Description ..............................................................

80

DTC Logic  ...............................................................

80

Diagnosis Procedure ...............................................

80

Special Repair Requirement  ...................................

80

POWER SUPPLY AND GROUND CIRCUIT  .....

81

STC-3

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Description ..............................................................

81

Diagnosis Procedure ...............................................

81

POWER STEERING SOLENOID VALVE  ..........

83

Description ..............................................................

83

Diagnosis Procedure ...............................................

83

Component Inspection  ............................................

84

RAS WARNING LAMP .......................................

85

Description ..............................................................

85

Component Function Check ....................................

85

Diagnosis Procedure ...............................................

85

Special Repair Requirement  ...................................

86

STOP LAMP SWITCH  ........................................

87

Description ..............................................................

87

Component Function Check ....................................

87

Diagnosis Procedure ...............................................

87

Component Inspection  ............................................

87

Special Repair Requirement  ...................................

88

ECU DIAGNOSIS INFORMATION ..............

89

RAS CONTROL UNIT  ........................................

89

Reference Value  .....................................................

89

Wiring Diagram - RAS SYSTEM -  ...........................

92

Fail-Safe ................................................................

100

DTC Inspection Priority Chart  ...............................

102

DTC Index  .............................................................

102

SYMPTOM DIAGNOSIS  ............................

105

RAS WARNING LAMP DOSE NOT TURN ON .

105

Description .............................................................

105

Diagnosis Procedure  .............................................

105

RAS WARNING LAMP DOSE NOT TURN 
OFF ..................................................................

106

Description .............................................................

106

Diagnosis Procedure  .............................................

106

UNBALANCE STEERING WHEEL TURNING 
FORCE (TORQUE VARIATION) .....................

107

Description .............................................................

107

Diagnosis Procedure  .............................................

107

PRECAUTION ............................................

108

PRECAUTIONS ...............................................

108

Precaution for Supplemental Restraint System 
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...............................................................

108

Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect  .................................

108

REMOVAL AND INSTALLATION  .............

109

RAS CONTROL UNIT  .....................................

109

Removal and Installation  .......................................

109

REAR ACTIVE STEER  ...................................

110

Exploded View .......................................................

110

Removal and Installation  .......................................

110

STC-4

< BASIC INSPECTION >

[WITHOUT REAR ACTIVE STEER]

DIAGNOSIS AND REPAIR WORK FLOW

BASIC INSPECTION

DIAGNOSIS AND REPAIR WORK FLOW

Work Flow

INFOID:0000000005235332

DETAILED FLOW

1.

COLLECT THE INFORMATION FROM THE CUSTOMER

It is also important to clarify customer complaints before inspection. First of all, reproduce symptoms and
understand them fully. Ask customer about his/her complaints carefully. In some cases, it is necessary to
check symptoms by driving vehicle with customer.

CAUTION:

Customers are not professional. It is dangerous to make an easy guess like “maybe the customer
means that...,” or “maybe the customer mentions this symptom”.

>> GO TO 2.

2.

CHECK THE STATUS

1.

Power steering fluid leakage and check the power steering fluid level. Refer to 

ST-12, "Inspection"

.

2.

Check the drive belt tension. Refer to 

EM-15, "Checking"

 (VQ35HR), 

EM-163, "Checking"

 (VK50VE).

3.

Check the power steering gear for damages, cracks and fluid leakage. Refer to 

ST-34, "Inspection"

.

4.

Check the relief oil pressure. Refer to 

ST-40, "VQ35HR : Inspection"

 (VQ35HR), 

ST-46, "VK50VE :

Inspection"

 (VK50VE).

>> GO TO 3.

3.

DIAGNOSIS CHART BY SYMPTOM

Perform the diagnosis by symptom. Refer to 

STC-25, "Diagnosis Procedure"

.

>> GO TO 4.

4.

FINAL CHECK

Check the input/output standard values for the power steering control unit.

Are the power steering control unit input/output values within standard ranges respectively?

YES

>> INSPECTION END

NO

>> GO TO 2.