NISSAN TEANA 2008 Service Manual

POWER STEERING CONTROL UNIT
STC-13
< ECU DIAGNOSIS >
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ECU DIAGNOSIS
POWER STEERING CONTROL UNIT
Reference ValueINFOID:0000000003893535
TERMINAL LAYOUT
PHYSICAL VALUES
JSGIA0023ZZ
Te r m i n a l N o .
(Wire color)Description
Condition Value (Approx.)
+ - Signal nameInput/
Output
1
(R/Y)GroundPower steering solenoid
valve voltageOutputVehicle speed: 0 km/h (0 MPH)
(Engine is running)4.4 – 6.6 V
Vehicle speed: 100 km/h (62 MPH) 2.4 – 3.6 V
3
(G/W)GroundIgnition switch power
supplyInputIgnition switch: ON Battery voltage
Ignition switch: OFF 0 V
5
(LG)GroundPower steering solenoid
valve ground—Always 0 V
6
(B)Ground Ground — Always 0 V
8
(L/B)Ground Vehicle speed signal InputVehicle speed: 40 km/h (25 MPH)
CAUTION:
Check air pressure of tire under
standard condition.
10
(V/W)Ground Engine speed signal InputEngine is running
 Warm-up condition
 Idle speed
Engine is running
 Warm-up condition
 Engine speed: Approx. 2,000 rpm
JSNIA0015GB
JSGIA0143ZZ
PBIA3655J

STC-14
< ECU DIAGNOSIS >
POWER STEERING CONTROL UNIT
CAUTION:
When using circuit tester or oscilloscope to measure voltage for inspection, be sure not to forcibly extend any connector ter-
minals.
Wiring Diagram - ELECTRONICALLY CONTROLLED POWER STEERING SYSTEM -
INFOID:0000000003893536
JCGWM0089GB

POWER STEERING CONTROL UNIT
STC-15
< ECU DIAGNOSIS >
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Fail-SafeINFOID:0000000003893835
EPS system
JCGWM0090GB

STC-16
< ECU DIAGNOSIS >
POWER STEERING CONTROL UNIT
 EPS system enters the fail-safe mode (that allows the steering
force to be controlled without impairing the drivability) if any of the
input/output values to/from EPS system (power steering control
unit) deviate from the standard range.
NOTE:
The system enters the fail-safe mode if the engine speed remains
at 1,500 rpm or more for over 10 seconds while the vehicle is
stopped. This is normal.
 The fail-safe function is canceled when a vehicle speed signal of 2
km/h (1.2 MPH) or more is inputted or the ignition switch is turned
OFF→ON. EPS system restores the normal operation at that time.
JSGIA0426GB
ModeWarn-
ing lampDTC Detection point (malfunction part) Error area and root cause
Fail-safe
function— — Vehicle speed signal input Engine speed is 1,500 rpm or more and there is no vehicle
speed signal input for over 10 seconds during vehicle travel.
 Vehicle speed signal has abruptly dropped from 30 km/h (19
MPH) or more to 2 km/h (1.2 MPH) or less within 1.4 sec-
onds.

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)
STC-17
< SYMPTOM DIAGNOSIS >
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SYMPTOM DIAGNOSIS
UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIA-
TION)
DescriptionINFOID:0000000003893538
 Hard steering when fully turning the steering wheel.
 Light steering when driving at a high speed.
Diagnosis ProcedureINFOID:0000000003893539
1.CHECK SYSTEM FOR POWER SUPPLY AND GROUND
Perform trouble diagnosis for power supply and ground. Refer to STC-6, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace damaged parts.
2.CHECK SYSTEM FOR VEHICLE SPEED SIGNAL
Perform trouble diagnosis for vehicle speed signal. Refer to STC-11, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK SYSTEM FOR ENGINE SPEED SIGNAL
Perform trouble diagnosis for engine speed signal. Refer to STC-9, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair or replace damaged parts.
4.CHECK SYSTEM FOR POWER STEERING SOLENOID VALVE
Perform trouble diagnosis for power steering solenoid valve. Refer to STC-7, "
Diagnosis Procedure".
Is the inspection result normal?
YES >> Perform the symptom diagnosis for the steering system. Refer to ST-2, "NVH Troubleshooting
Chart".
NO >> Repair or replace damaged parts.

STC-18
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000003971959
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. Information necessary to service the system safely is included in the “SRS AIRBAG” and
“SEAT BELT” of this Service Manual.
WARNING:
 To avoid rendering the SRS inoperative, 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 incorrect removal and installation of the SRS, can lead to personal
injury caused by unintentional activation of the system. For removal of Spiral Cable and Air Bag
Module, see the “SRS AIRBAG”.
 Never use electrical test equipment on any circuit related to the SRS unless instructed to in this Ser-
vice Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or harness
connectors.
Precaution Necessary for Steering Wheel Rotation after Battery Disconnect
INFOID:0000000003893541
NOTE:
 Before removing and installing any control units, first turn the push-button ignition switch to the LOCK posi-
tion, then disconnect both battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnosis according to self-diagnosis results.
This vehicle is equipped with a push-button ignition switch and a steering lock unit.
If the battery is disconnected or discharged, the steering wheel will lock and cannot be turned.
If turning the steering wheel is required with the battery disconnected or discharged, follow the procedure
below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables.
NOTE:
Supply power using jumper cables if battery is discharged.
2. Carry the Intelligent Key or insert it to the key slot and turn the push-button ignition switch to ACC position.
(At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock will remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
5. When the repair work is completed, re-connect both battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button ignition switch is turned to LOCK position.)
6. Perform self-diagnosis check of all control units using CONSULT-III.

POWER STEERING CONTROL UNIT
STC-19
< ON-VEHICLE REPAIR >
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ON-VEHICLE REPAIR
POWER STEERING CONTROL UNIT
Exploded ViewINFOID:0000000003893542
Removal and InstallationINFOID:0000000003893543
REMOVAL
1. Remove glove box assembly. Refer to IP-11, "Exploded View".
2. Disconnect power steering control unit connector.
3. Remove power steering control unit.
INSTALLATION
Install in the reverse order of removal.
1. Steering member 2. Power steering control unit
: Vehicle front
JSGIA0407ZZ

STR-1
ENGINE
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SECTION STR
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CONTENTS
STARTING SYSTEM
BASIC INSPECTION ....... .............................2
DIAGNOSIS AND REPAIR WORKFLOW ..... .....2
Work Flow ........................................................... ......2
FUNCTION DIAGNOSIS ...............................5
STARTING SYSTEM ...................................... .....5
VQ25DE ................................................................. ......5
VQ25DE : System Diagram ......................................5
VQ25DE : System Description ..................................5
VQ25DE : Component Parts Location ......................5
VQ25DE : Component Description ...........................6
VQ35DE ................................................................. ......6
VQ35DE : System Diagram ......................................6
VQ35DE : System Description ..................................6
VQ35DE : Component Parts Location ......................7
VQ35DE : Component Description ...........................7
COMPONENT DIAGNOSIS ..........................8
B TERMINAL CIRCUIT .................................. .....8
Description .......................................................... ......8
Diagnosis Procedure .................................................8
S TERMINAL CIRCUIT .......................................9
Description .......................................................... ......9
Diagnosis Procedure .................................................9
STARTING SYSTEM ..........................................10
Wiring Diagram - STARTING SYSTEM - ............ ....10
SYMPTOM DIAGNOSIS ..............................13
STARTING SYSTEM .........................................13
Symptom Table ................................................... ....13
PRECAUTION ..............................................14
PRECAUTIONS .................................................14
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ....
14
ON-VEHICLE REPAIR .................................15
STARTER MOTOR ...........................................15
VQ25DE ................................................................. ....15
VQ25DE : Exploded View ........................................15
VQ25DE : Removal and Installation ........................16
VQ25DE : Inspection ...............................................16
VQ35DE ................................................................. ....20
VQ35DE : Exploded View ........................................20
VQ35DE : Removal and Installation ........................21
VQ35DE : Inspection ...............................................22
SERVICE DATA AND SPECIFICATIONS
(SDS) ............... .............................................
26
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
26
Starter Motor ....................................................... ....26

STR-2
< BASIC INSPECTION >
DIAGNOSIS AND REPAIR WORKFLOW
BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
Work FlowINFOID:0000000003860412
OVERALL SEQUENCE
DETAILED FLOW
JPBIA0502GB

DIAGNOSIS AND REPAIR WORKFLOW
STR-3
< BASIC INSPECTION >
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NOTE:
If any malfunction is found, immediately disconnect the battery cable from the negative terminal.
1.CHECK ENGINE START
Crank the engine and check that the engine starts.
Does the engine start?
YES >> GO TO 2.
NO >> GO TO 3.
2.CHECK THAT THE STARTER MOTOR STOPS
Check that the starter motor stops after starting the engine.
Does the starter motor stop?
YES >> INSPECTION END
NO >> Replace magnetic switch.
3.CHECK THE ENGINE SPEED WITH CRANKING
Check that the engine turns at cranking.
Does engine turn by cranking?
YES >> GO TO 4.
NO >> GO TO 5.
4.CHECK THE ENGINE SPEED WITH CRANKING
Check that the engine speed is not low at cranking.
Does engine turn normally?
YES >> Check ignition/fuel system.
NO >> Check charge condition, corrosion and connection condition of the battery. Refer to STR-2, "
Work
Flow".
5.CHECK STARTER MOTOR ACTIVATION
Check that the starter motor turns at cranking.
Does starter motor turn?
YES >> GO TO 6.
NO >> GO TO 7.
6.CHECK STARTER MOTOR UNIT
1. Remove starter motor.
2. Check that the gear shaft of starter motor rotates.
Does gear shaft turn?
YES >> Check pinion clutch. Refer to the following.
• VQ25DE models: STR-16, "
VQ25DE : Inspection"
 VQ35DE models: STR-22, "VQ35DE : Inspection"
NO >> Check reduction gear, armature and gear shaft.
7.CHECK POWER SUPPLY CIRCUIT
Check the following conditions.
 Fuse and fusible link
 Charge condition, corrosion and connection condition of the battery. Refer to STR-2, "
Work Flow".
Are these inspection results normal?
YES >> GO TO 8.
NO >> Repair as needed.
8.CHECK STARTING SYSTEM WIRING
Check the following.
 “B” terminal circuit. Refer to STR-8, "
Diagnosis Procedure".
 “S” terminal circuit. Refer to STR-9, "
Diagnosis Procedure".
Are these inspection results normal?
YES >> GO TO 9.