2007 INFINITI M35 steering

TROUBLE DIAGNOSIS
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Revision: 2007 April2007 M35/M45
TROUBLE DIAGNOSISPFP:00004
How to Perform Trouble DiagnosisNGS000DX
BASIC CONCEPT

The most important point to perform trouble diagnosis is to understand systems (control and mechanism)
in vehicle thoroughly.

It is also important to clarify customer complaints before inspec-
tion.
First of all, reproduce symptom, and understand it fully.
Ask customer about his/her complaints carefully. In some cases,
they will be necessary to check symptom by driving vehicle with
customer.
CAUTION:
Customers are not professionals. Do not assume “maybe
customer means...” or “maybe customer mentioned this
symptom”.

It is essential to check symptoms right from beginning in order to
repair a malfunction completely.
For an intermittent malfunction, it is important to reproduce
symptom based on interview with customer and past examples.
Do not perform inspection on ad hoc basis. Most intermittent
malfunctions are caused by poor contacts. In this case, it will be
effective to shake suspected harness or connector by hand.
When repairs are performed without any symptom check, no
one can judge if malfunction has actually been eliminated.

Always read “GI General Information” to confirm general precau-
tions. Refer to GI-4, "
General Precautions" .
Component Parts LocationNGS000DY
SEF234G
SEF233G
1. Power steering control unit
(Back of center console assembly)2. Power steering solenoid valve
SGIA1105J

TROUBLE DIAGNOSIS
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Revision: 2007 April2007 M35/M45
For Fast and Accurate Trouble DiagnosisNGS000E1
Check the following items with the vehicle stopped

Is air pressure and size of tires proper?

Is the specified part used for the steering wheel?

Is control unit a genuine part?

Are there any fluid leakage from steering gear assembly, power steering oil pump, and hydraulic pipes,
etc? Refer to PS-8, "
Checking Fluid Leakage" .

Is the fluid level proper? Refer to PS-8, "Checking Fluid Level" .

Is the wheel alignment adjusted properly? Refer to FSU-6, "Wheel Alignment Inspection" (2WD), FSU-24,
"Wheel Alignment Inspection" (AWD).

Are there any damage or modification to suspension or body resulting in increased weight or altered
ground clearance?

Check each link installation condition of suspension and axle.

Check each connector connection condition.
Check the following items while driving the vehicle

Check conditions when the malfunction occurred (5W 1H).

Is the engine condition normal?
Basic InspectionNGS000E2
POWER SUPPLY CIRCUIT TERMINAL LOOSENESS AND BATTERY
Check battery terminals for looseness on both positive and negative ones and ground connection. Also make
sure that battery voltage does not drop.
Inspection: Power Steering Control Unit Power Supply Circuit and GroundNGS000E3
1. CHECK POWER STEERING CONTROL UNIT CONNECTOR
Turn ignition switch OFF, disconnect power steering control unit harness connector, and check terminal for
deformation, disconnection, looseness, etc.
OK or NG
OK >> GO TO 2.
NG >> Connector terminal connection is loose, damaged, open, or shorted. Repair or replace the termi-
nal.
2. CHECK POWER STEERING CONTROL UNIT GROUND CIRCUIT
Disconnect power steering control unit harness connector M8, and
then check continuity between power steering control unit harness
connector M8 and ground.
OK or NG
OK >> GO TO 3.
NG >> Ground circuit open or shorted. Repair or replace any
inoperative parts. Terminal 2 – Ground : Continuity exist.
SGIA1231E

STC-10
[EPS]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
3. CHECK POWER STEERING CONTROL UNIT POWER SUPPLY CIRCUIT
Turn ignition switch ON, and then check voltage between power
steering control unit harness connector M8 and ground.
OK or NG
OK >> Power supply and ground circuit are normal.
NG >> Power supply circuit open or shorted. Repair or replace
any inoperative parts.
Symptom: The Steering Force Does Not Change Smoothly According to the
Vehicle Speed
NGS000E4
Heavy steering force with the static steering/light steering force during high-speed driving
1. POWER STEERING SOLENOID VALVE SIGNAL INSPECTION 1
1. Start engine.
2. Change the vehicle speed from 0 to 100 km/h (0 to 62 MPH)
slowly, and then check voltage between power steering control
unit harness connector M8 and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 7.
2. POWER STEERING SOLENOID VALVE SIGNAL INSPECTION 2
1. Activate fail-safe function by running the engine speed at 1,500 rpm or higher for 10 seconds with the
vehicle stopped.
2. Change the engine speed to the idling, to approximately 1,600
rpm, and to approximately 3,000 rpm slowly, and then check
voltage between power steering control unit harness connector
M8 and ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 8.
3. CHECK POWER STEERING SOLENOID VALVE CONNECTOR
Turn ignition switch OFF, disconnect power steering solenoid valve harness connector, and check terminal for
deformation, disconnection, looseness, etc.
OK or NG
OK >> GO TO 4.
NG >> Harness or connector open or shorted. Repair or replace any inoperative parts.Terminal 1 – ground : Battery voltage (Approx. 12 V)
SGIA1232E
Terminal 7 – ground : The voltage has changed from
approximately 4.4 - 6.6 V to
approximately 2.4 - 3.6 V
SGIA1233E
Terminal 7 – ground : The voltage has changed from
approximately 5.5 V to approxi-
mately 2.1 V step-by-step.
SGIA1233E

TROUBLE DIAGNOSIS
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Revision: 2007 April2007 M35/M45
4. CHECK POWER STEERING SOLENOID VALVE POWER SUPPLY CIRCUIT
Check continuity between power steering control unit harness con-
nector M8 and power steering solenoid valve harness connector F25
(VQ35DE), E211 (VK45DE).
OK or NG
OK >> GO TO 5.
NG >> Open or short in harness. Repair or replace any inoper-
ative parts.
5. CHECK POWER STEERING SOLENOID VALVE GROUND CIRCUIT
Check continuity between power steering solenoid valve harness
connector F25 (VQ35DE), E211 (VK45DE) and ground.
OK or NG
OK >> GO TO 6.
NG >> Open or short in harness. Repair or replace any inoper-
ative parts.
6. CHECK POWER STEERING SOLENOID VALVE
Apply voltage power steering solenoid valve connector, and then
make sure that the operating sound (clicking sound) is heard.
OK or NG
OK >> Perform steering wheel turning force inspection. Refer
to PS-10, "
CHECKING STEERING WHEEL TURNING
FORCE" .
NG >> Power steering solenoid valve is inoperative. Replace.
Power steering control unit Power steering solenoid valve Continuity
Terminal 7 Terminal 1 Yes
SGIA1235E
Terminal 2 – Ground : Continuity exist.
SGIA1236E
Terminal 1 (+) - 2 (–) : Operating sound is heard.
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STC-12
[EPS]
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
7. CHECK VEHICLE SPEED SIGNAL CIRCUIT
Change the vehicle speed, and then check voltage waveform
between power steering control unit harness connector M8 and
ground.
OK or NG
OK >> Power steering control unit is inoperative. Replace it.
NG >> Check the following systems and replace if necessary.

Harness between unified meter & A/C amp and power steering control unit.

Unified meter & A/C amp and vehicle speed signal circuit Refer to DI-28, "UNIFIED METER
AND A/C AMP" .
8. CHECK ENGINE SPEED SIGNAL CIRCUIT
Warm up the engine, and then check voltage waveform between
power steering control unit harness connector M8 and ground when
the engine speed is the idling and at approximately 2,000 rpm.
OK or NG
OK >> Power steering control unit is inoperating. Replace it.
NG >> Check the following systems and replace if malfunction is detected.

Harness between ECM and power steering control unit

ECM engine speed signal circuit. Refer to EC-826, "CONSULT-II Function (ENGINE)" .
Terminal 3 – GroundRepeat Approx. 0 V and approx. 5 V
SGIA1237EELF1080D
Terminal 5 – GroundAt Idle
Approx. 2,000 rpmSGIA1289EPBIA3654J
PBIA3655J

STC-14
[RAS]
REAR ACTIVE STEER
Revision: 2007 April2007 M35/M45
Disassembly and AssemblyNGS000E6
COMPONENTS
DISASSEMBLY
1. Remove mounting bolts of RAS motor assembly, and then remove RAS motor assembly, ground terminal,
O-ring from RAS actuator.
2. Remove mounting bolt of rear wheel steering angle sensor, and then remove rear wheel steering angle
sensor, O-ring from RAS actuator.
INSPECTION AFTER DISASSEMBLY
Check RAS actuator bracket (rear wheel steering angle sensor mounting area) for crush, deformation, cracks,
or other damage. Replace the RAS actuator malfunction is detected.
ASSEMBLY

Assembly is the reverse order of disassembly. For tightening torque, refer to STC-14, "COMPONENTS" .

After assembling RAS actuator assembly (after removing and installing rear wheel steering angle sensor
and RAS motor), perform the neutral position adjustment.
Neutral Position AdjustmentNGS000E7
Adjust neutral position after performing the following procedure.

Removing and installing or replacing the RAS actuator assembly

Disassembling the RAS actuator assembly (when removing rear wheel steering angle sensor and RAS
motor)
CAUTION:
Perform the neutral position adjustment after installing the RAS actuator assembly to the vehicle.
Before that, remove the rear lower link from the RAS actuator.
1. Disconnect harness connector and remove rear wheel steering angle sensor from the RAS actuator
assembly.
2. Disconnect RAS motor harness connector.
3. Turn ignition switch ON.
1. Ground terminal 2. RAS motor assembly 3. O-ring
4. RAS actuator 5. Rear wheel steering angle sensor
Refer to GI-11, "
Components" , for the symbols in the figure.
SGIA1052J

REAR ACTIVE STEER
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Revision: 2007 April2007 M35/M45
4. Supply 6 V voltage by connecting the four 1.5 V batteries in a
series. Connect them to the RAS motor connector (motor side),
and then operate the motor and adjust the rack in the neutral
position (A).
CAUTION:
Do not supply 12 V voltage (battery, etc) to the RAS motor.
NOTE:
For right stroke, connect positive probe to the RAS motor con-
nector terminal 1. For left stroke, connect it to the terminal 2.
5. Install rear wheel steering angle sensor with O-ring to the RAS
actuator assembly. Temporarily tighten the mounting bolts in the specified torque that the sensor can be
moved by hand.
6. Turn and adjust the rear wheel steering angle sensor so as to make each sensor signal of “DATA MONI-
TOR” mode to the following standard with CONSULT-II.
CAUTION:
During DATA MONITOR mode, “MONITORING ERROR” is displayed. But there is not malfunction
in this procedure.
7. Tighten rear wheel steering angle sensor mounting bolts.
8. Perform “ERASE” with CONSULT-II, and then erase the error memory of rear wheel steering angle sen-
sor. Refer to STC-29, "
How to Erase Self-Diagnostic Results" .
9. Perform CONSULT-II “SELF-DIAG RESULTS” again, and then make sure that there is no malfunction.
Refer to STC-28, "
SELF-DIAG RESULT MODE" . Full stroke (B) : 6.8 - 7.2 mm (0.268 - 0.283 in)
STEERING ANG (°) L - 0, R - 0, N - 0
RR ST ANG-MAI (V) Approx. 2.4
RR ST ANG-SUB (V) Approx. 2.4
RR ST ANG-VOL (V) Approx. 5.0
SGIA1240E

STC-16
[RAS]
SYSTEM DESCRIPTION
Revision: 2007 April2007 M35/M45
SYSTEM DESCRIPTIONPFP:00000
ComponentsNGS000E8
RAS (Rear Active Steer) FunctionNGS000E9
A. RAS control unit B. Model following control C. Target vehicle dynamics model
D. Rear wheel steering angle com-
mand value operationE. Rear wheel steering angle servo F. Vehicle speed signal (CAN)
G. Steering angle signal (CAN) H. Vehicle speed sensor I. Steering angle sensor
J. RAS actuator assembly
SGIA1241E
Part name Function
RAS control unit

Calculate the vehicle speed signal from CAN communication and the signals from steering
angle sensor and rear wheel steering angle sensor by a computer, and then control the rear
wheel steering angle.

Fail-safe function is activated when the electrical system is malfunctioning. The output signal
to the actuator is turned OFF during this mode. At that time, the RAS warning lamp illumi-
nates and indicates the system is malfunctioning.

It performs the communication control function with other control units via CAN communica-
tion.

This enables system diagnosis with CONSULT-II.
RAS actuatorThe efficiency of the rear wheel steer improves by locating the electric motor actuator into the
lower link of rear suspension.
Steering angle sensor

Measure the steering angle and send it to RAS control unit via CAN communication.

It is shared with the steering angle sensor for VDC.
Rear wheel steering angle sensor

It sends the rear wheel steering angle status to RAS control unit. The accuracy of rear wheel
steer improves by comparing the vehicle speed signal from CAN communication with the
rear wheel steering angle target value calculated from the wheel angle sensor signal, and it
controls them.

There are 2 types of rear wheel steering angle sensors (main/sub). If one of them is malfunc-
tioning, the other operates the fail-safe mode and stops the control.
RAS warning lamp

It turns on when the fail-safe function is operated and indicates that a RAS control malfunc-
tion has occurred.

It turns on when ignition switch turns on and turns off after the engine is started.

It indicates the suspect system by blinking when performing the self-diagnosis (without CON-
SULT-II).