STC-1
STEERING
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CONTENTS
STEERING CONTROL SYSTEM
PRECAUTION ................ ...............................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Service Notice and Precautions for Hydraulic
Pump Electric Power Steering System ............... ......
3
SYSTEM DESCRIPTION ..............................4
COMPONENT PARTS ................................... .....4
Component Parts Location .................................. ......4
Component Description .............................................4
Power Steering Oil Pump Assembly .........................5
SYSTEM ..............................................................6
HYDRAULIC PUMP ELECTRIC POWER STEER-
ING SYSTEM ........ ................................. ......................
6
HYDRAULIC PUMP ELECTRIC POWER
STEERING SYSTEM : System Description ..............
6
HYDRAULIC PUMP ELECTRIC POWER
STEERING SYSTEM : Fail-sa fe ......................... ......
8
HYDRAULIC PUMP ELECTRIC POWER
STEERING SYSTEM : Protec tion Function ..............
9
DIAGNOSIS SYSTEM (POWER STEERING
CONTROL MODULE) .................................... ....
10
CONSULT Function ............................................ ....10
ECU DIAGNOSIS INFORMATION ..............11
POWER STEERING CONTROL MODULE .... ....11
Reference Value ................................................. ....11
Fail-safe ..................................................................12
Protection Function .................................................12
DTC Inspection Priority Chart ............................. ....13
DTC Index ........................................................... ....13
WIRING DIAGRAM ......................................14
HYDRAULIC PUMP ELECTRIC POWER
STEERING SYSTEM .........................................
14
Wiring Diagram .................................................... ....14
BASIC INSPECTION ...................................19
DIAGNOSIS AND REPAIR WORK FLOW .......19
Work Flow ............................................................ ....19
Diagnostic Work Sheet ............................................20
DTC/CIRCUIT DIAGNOSIS .........................22
C1143 STEERING ANGLE SENSOR ...............22
DTC Logic ............................................................ ....22
Diagnosis Procedure ...............................................22
C1601 BATTERY POWER SUPPLY ................23
DTC Logic ................................................................23
Diagnosis Procedure ...............................................23
C1602 NO TUNING SET ...................................26
DTC Logic ................................................................26
Diagnosis Procedure ...............................................26
C1606 EPS MOTOR ..........................................27
DTC Logic ................................................................27
Diagnosis Procedure ...............................................27
C1607, C1608 POWER STEERING CON-
TROL MODULE ................................................
28
DTC Logic ............................................................ ....28
Diagnosis Procedure ...............................................28
C160A HEAT PROTECTION ............................29
DTC Logic ................................................................29
U1000 CAN COMM CIRCUIT ...........................30
Description ...............................................................30
DTC Logic ................................................................30
Diagnosis Procedure ...............................................30
HYDRAULIC PUMP ELECTRIC POWER
STEERING WARNING LAMP ...........................
31
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PRECAUTIONSSTC-3
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000009951730
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. Information necessary to service t he system safely is included in the SR and SB section of
this Service Manual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers , always switch the Ignition OFF, disconnect the
battery and wait at least three mi nutes before performing any service.
Service Notice and Precautions for Hydrau lic Pump Electric Power Steering System
INFOID:0000000009460340
• Check each tire for proper air pressure and size. Refer to WT-60, "Tire".
• Verify that the steering system components are G enuine NISSAN parts and have been installed properly.
• Check the steering column for loose mounting bolts.
• Check the steering gear assembly for loose mounting bolts. Check the inner sockets and outer sockets for
damage or wear. Inspect the boots and seals for leakage of power steering fluid.
• Verify proper wheel alignment. Refer to FSU-7, "Inspection and Adjustment"
.
• Check for any damage, wear, or modification to the suspension and body that would result in increased
weight or an improper wheelarch height. Refer to FSU-26, "Wheelarch Height (Unladen*
1)".
• Check for proper battery voltage.
• Verify that all power steering pump assembly connections are clean and fully seated.
• Verify that only Genuine NISSAN E-PSF is used. Use of any power steering fluid other than Genuine NIS-
SAN E-PSF will prevent the power st eering system from proper operation.
• An audible high pitch noise may be heard from the engine compartment when the steering wheel is oper-
ated, particularly at low speeds such as a parking lot maneuver. This condition is not a malfunction, rather
normal system operation. Steering at low speeds or parking lot maneuvers demands higher hydraulic assis-
tance, resulting in larger power st eering pump load and increased system noise.
• The power steering pump is electrically controlled by the power steering control module.
• Before connecting or disconnecting the power steeri ng control module harness connectors, turn ignition
switch “OFF” and disconnect battery ground cable. Batter y voltage is applied to power steering control mod-
ule even if ignition switch is turned “OFF”.
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STC-4
< SYSTEM DESCRIPTION >
COMPONENT PARTS
SYSTEM DESCRIPTION
COMPONENT PARTS
Component Parts LocationINFOID:0000000009460341
Component DescriptionINFOID:0000000009460342
1. Power steering oil pump assembly 2. Steering angle sensor(view with the steering wheel re-
moved) 3. ECM
4. Combination meter 5. EPS warning light
ALGIA0128ZZ
Component parts Reference
Power steering oil pump assembly STC-5, "Power Steering Oil Pump Assembly"
Steering angle sensorTransmits steering angle sensor signal to the power steering control module via CAN commu-
nication.
ECM Transmits engine speed signal to the power steering control module via CAN communication.
Combination meter Transmits vehicle speed signal to the power steering control module via CAN communication.
The combination meter also di splays the EPS warning light.
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COMPONENT PARTSSTC-5
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Power Steering Oil Pump AssemblyINFOID:0000000009460343
The power steering oil pump assembly is primarily composed of the
reservoir tank (1), power steering oil pump (2), power steering motor
(3), and power steering control module (4).
RESERVOIR TANK
Fluid is filled from the reservoir tank.
POWER STEERING OIL PUMP
The power steering oil pump is driven by the power steer ing motor and generates hydraulic oil pressure in the
system.
POWER STEERING MOTOR
The power steering motor is controll ed by the power steering control module and drives the power steering oil
pump.
POWER STEERING CONTROL MODULE
By receiving steering angle sensor signal and vehicle speed signal, the power steering control module calcu-
lates hydraulic pressure of the hydraulic pump electric power steering system according to the driving condi-
tions. The power steering control modul e controls the power steering motor.
JSGIA0914ZZ
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STC-6
< SYSTEM DESCRIPTION >
SYSTEM
SYSTEM
HYDRAULIC PUMP ELECTRIC POWER STEERING SYSTEM
HYDRAULIC PUMP ELECTRIC POWER ST EERING SYSTEM : System Description
INFOID:0000000009460344
• The system is composed primarily of the power steeri ng oil pump assembly (power steering control module,
power steering motor, power steering oil pump, and reservoir tank), hydraulic pipes, and steering gear
assembly.
• The power steering control module controls the speed of the power steering motor according to the vehicle
speed and steering angle speed. By changing the power st eering oil pump flow, the power steering control
module controls the steering assist force.
• According to the power steering motor control, the sy stem hydraulic pressure is transmitted from the power
steering motor to power steering oil pump. The power steering oil pump is driven by the system hydraulic
pressure.
• After engine start, the hydraulic pump electric power steering system performs control.
• When a malfunction occurs in the system, the fail-safe function stops the hydraulic pump electric power
steering system (manual steering state) or restricts it s operation (certain steering assist force). Refer to STC-
8, "HYDRAULIC PUMP ELECTRIC POWER STEERING SYSTEM : Fail-safe".
• When the power steering function is used continuously in an extreme manner, the protective function
reduces the output to the power steering motor. Refer to STC-9, "HYDRAULIC PUMP ELECTRIC POWER
STEERING SYSTEM : Protection Function".
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL
Communicates the signal from each control unit via CAN communication.
OPERATION CHARACTERISTICS
ALGIA0127GB
Control unit Signal status
ECM Transmits engine status signal to power steering control module via CAN communication.
Steering angle sensor Transmits steering angle sensor signal to power steering control module via CAN commu-
nication.
Combination meter Transmits vehicle speed signal to power steering control module via CAN communication.
Receives hydraulic pump electric power steering warning lamp signal from power steering
control module via CAN communication.
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STC-22
< DTC/CIRCUIT DIAGNOSIS >
C1143 STEERING ANGLE SENSOR
DTC/CIRCUIT DIAGNOSIS
C1143 STEERING ANGLE SENSOR
DTC LogicINFOID:0000000009460356
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC CONFIRMATION PROCEDURE has been previously conducted, always turn ignition switch OFF and
wait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.DTC REPRODUCTION PROCEDURE
With CONSULT
1. Turn the ignition switch OFF to ON.
2. Perform PS self-diagnosis.
Is DTC C1143 detected?
YES >> Proceed to diagnosis procedure. Refer to STC-22, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000009460357
1.CHECK STEERING ANGLE SENSOR CIRCUIT
Check steering angle sensor circuit. Refer to BRC-88, "Diagnosis Procedure"
.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace malfunctioning component.
2.CHECK TERMINALS AND HARNESS CONNECTORS
Check the power steering control module pin termi nals for damage or loose connection with harness connec-
tor.
Is the inspection result normal?
YES >> Power steering control module is malfunctioni ng. Replace power steering oil pump assembly.
Refer to ST-38, "Removal and Installation"
.
NO >> Repair or replace malfunctioning component.
DTC Display item Malfunction detected condition Possible cause
C1143 ST ANG SEN CIRCUIT When a malfunction is detected in steering angle
sensor. • Harness or connector
• Steering angle sensor
• Power steering control mod-
ule
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STEERING WHEEL TURNING FORCE IS HEAVY OR LIGHTSTC-35
< SYMPTOM DIAGNOSIS >
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6.CHECK THE POWER STEERING CONTROL MODULE SIGNAL (5)
With CONSULT
Select “STR ANG SPD” in “DATA MONITOR” of “EPS”.
Is the check result normal?
YES >> GO TO 7.
NO >> Check the steering angle sensor. Refer to STC-22, "Diagnosis Procedure"
.
7.CHECK THE POWER STEERING CONTROL MODULE SIGNAL (6)
With CONSULT
Select “ENGINE STATUS” in “DATA MONITOR” of “EPS”.
Is the display value
“RUN”?
YES >> GO TO 8.
NO >> Check the ECM. Refer to EC-77, "CONSULT Function"
.
8.CHECK THE STEERING FORCE
Check the steering force. Refer to STC-36, "Diagnosis Procedure"
.
Is the check result normal?
YES >> Inspection End.
NO >> It is possible that there is a mechani cal malfunction. Check the steering system.
Monitor item Test condition Display value
STR ANG SPD The steering wheel is not
steered. Approx. 0.0 deg/s
The steering wheel is steered. Displays steering angle speed
(deg/s)
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STC-38
< SYMPTOM DIAGNOSIS >
UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)
NO >> Check the combination meter, ABS actuator and electric unit (control unit). Refer to MWI-18,
"CONSULT Function (METER/M&A)" and BRC-33, "CONSULT Function (ABS)".
6.CHECK THE POWER STEERING CONTROL MODULE SIGNAL (5)
With CONSULT
Select “STR ANG SPD” in “DATA MONITOR” of “EPS”.
Is the check result normal?
YES >> GO TO 7.
NO >> Check the steering angle sensor. Refer to STC-22, "Diagnosis Procedure"
.
7.CHECK THE POWER STEERING CONTROL MODULE SIGNAL (6)
With CONSULT
Select “ENGINE STATUS” in “DATA MONITOR” of “EPS”.
Is the display value
“RUN”?
YES >> GO TO 8.
NO >> Check the ECM. Refer to EC-77, "CONSULT Function"
.
8.CHECK STEERING COLUMN AND STEERING GEAR
Check the steering column assembly and steering gear assembly.
• Steering column assembly. Refer to ST-46, "Steering Column"
.
• Steering gear assembly. Refer to ST-47, "Power Steering Gear"
.
Is the inspection result normal?
YES >> GO TO 9.
NO >> Repair or replace malfunctioning component.
9.CHECK STEERING WHEEL TURNING FORCE
Check the steering wheel turning force. Refer to STC-34, "Diagnosis Procedure"
.
Is the inspection result normal?
YES >> Inspection End.
NO >> Check the steering wheel turning force for mechanical malfunction. Refer to STC-34, "Diagnosis
Procedure".
Monitor item Test condition Display value
STR ANG SPD The steering wheel is not turn-
ing. Approx. 0.0 deg/s
The steering wheel is being
turned. Displays steering angle speed
(deg/s)
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