unified meter control unit INFINITI M35 2007 Factory Repair Manual

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

AWD SYSTEM
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Revision: 2007 April2007 M35/M45
COMPONENTS FUNCTION DESCRIPTION
CAN CommunicationNDS000DE
SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
For details, refer to LAN-50, "
CAN System Specification Chart" .
Component parts Function
AWD control unit

Controls driving force distribution by signals from each sensor and switch from rear wheel driving
mode (0:100) to AWD mode (50:50).

2WD mode is available by fail-safe function if malfunction is detected in AWD system.
Wheel sensors Detects wheel speed.
AWD solenoid Controls electric controlled coupling by command current from AWD control unit.
Electric controlled coupling Transmits driving force to front final drive.
AWD warning lamp

Illuminates if malfunction is detected in electrical system of AWD system.

There is 1 blink in 2 seconds if rotation difference of front wheels and rear wheels is large.

There are 2 blinks in 1 second if load is still applied to driving parts.
ABS actuator and electric unit
(control unit)Transmits the following signals via CAN communication to AWD control unit.

Vehicle speed signal

Stop lamp switch signal (brake signal)
ECMTransmits the following signals via CAN communication to AWD control unit.

Accelerator pedal position signal

Engine speed signal
Unified meter and A/C amp. Transmits conditions of parking brake switch via CAN communication to AWD control unit.

TF-20
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
Trouble Diagnosis Chart for SymptomsNDS000DK
If AWD warning lamp turns ON, perform self-diagnosis. Refer to TF-22, "SELF-DIAG RESULT MODE" .
NOTE:
Light tight-corner braking symptom may occur depending on driving conditions. This is not malfunction.
AWD Control Unit Input/Output Signal Reference ValuesNDS000DL
AWD CONTROL UNIT INSPECTION TABLE
Specifications with CONSULT-II
Symptom Condition Check item Reference page
AWD warning lamp does not turn ON when
the ignition switch is turned to ON.
(AWD warning lamp check)Ignition switch: ONCAN communication line
TF-33
Unified meter and A/C amp.
Unified meter control unit
AWD warning lamp does not turn OFF sev-
eral seconds after engine started.Engine runningCAN communication line
TF-33
Power supply and ground for AWD con-
trol unit
Unified meter and A/C amp.
Unified meter control unit
AWD solenoid
AWD actuator relay (integrated in AWD
control unit)
Wheel sensor
Heavy tight-corner braking symptom occurs
when the vehicle is driven and the steering
wheel is turned fully to either side after the
engine is started. (See NOTE.)

While driving

Steering wheel is
turned fully to either
sidesCAN communication line
TF-35Accelerator pedal position signal
AWD solenoid
Mechanical malfunction of electric con-
trolled coupling (clutch sticking etc.)
Vehicle does not enter AWD mode even
though AWD warning lamp turned to OFF.While drivingCAN communication line
TF-36
AWD solenoid
Mechanical malfunction of electric con-
trolled coupling (Mechanical engage-
ment of clutch is not possible.)
While driving, AWD warning lamp flashes
rapidly. (When flashing in approx. 1 minute
and then turning OFF.)
Rapid flashing: 2 times/secondWhile drivingProtection function is activated due to
heavy load to electric controlled cou-
pling. (AWD system is not malfunction-
ing. Also, optional distribution of torque
sometimes becomes rigid before lamp
flashes rapidly, but it is not malfunction.)TF-37
While driving, AWD warning lamp flashes
slowly. (When continuing to flash until turn-
ing ignition switch OFF)
Slow flashing: 1 time/2 seconds
While driving

Vehicle speed: 20 km/h
(12 MPH) or moreTire size is different between front and
rear of vehicle.TF-37
Monitor item [Unit] Content Condition Display value
FR RH SENSOR [km/h] or [mph]Wheel speed (Front wheel
right)Vehicle stopped 0.00 km/h (0.00 mph)
Vehicle running
CAUTION:
Check air pressure of tire under
standard condition.Approximately equal to
the indication on speed-
ometer (Inside of ±10%)
FR LH SENSOR [km/h] or [mph]Wheel speed (Front wheel
left)Vehicle stopped 0.00 km/h (0.00 mph)
Vehicle running
CAUTION:
Check air pressure of tire under
standard condition.Approximately equal to
the indication on speed-
ometer (Inside of ±10%)

TROUBLE DIAGNOSIS FOR SYMPTOMS
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Revision: 2007 April2007 M35/M45
TROUBLE DIAGNOSIS FOR SYMPTOMSPFP:00007
AWD Warning Lamp Does Not Turn ON When The Ignition Switch Is Turned to
ON
NDS000DU
DIAGNOSTIC PROCEDURE
1. CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to TF-22, "
SELF-DIAG RESULT MODE" .
Is the
“CAN COMM CIRCUIT [U1000]” displayed?
YES >> Perform trouble diagnosis for CAN communication line. Refer to TF-32, "CAN Communication
Line" .
NO >> GO TO 2.
2. CHECK AWD CONTROL UNIT
Check AWD control unit input/output signal. Refer to TF-20, "
AWD Control Unit Input/Output Signal Reference
Va l u e s" .
OK or NG
OK >> GO TO 3.
NG >> Check AWD control unit pin terminals for damage or loose connection with harness connector. If
any items are damaged, repair or replace damaged parts.
3. CHECK OUTPUT SIGNAL WITH UNIFIED METER AND A/C AMP.
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “METER A/C AMP” with CONSULT-II.
3. Start the engine, and then make sure that “4WD W/L” display
turns from "ON" to "OFF" after several seconds.
OK or NG
OK >> GO TO 4.
NG >> Perform trouble diagnosis for combination meter. Refer
to DI-18, "
Trouble Diagnosis" .
4. SYMPTOM CHECK
Check again.
OK or NG
OK >>INSPECTION END
NG >> Replace unified meter control unit assembly. Refer to DI-27, "
Disassembly and Assembly of Com-
bination Meter" .
AWD Warning Lamp Does Not Turn OFF Several Seconds after Engine StartedNDS000DV
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to TF-22, "
SELF-DIAG RESULT MODE" .
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
Monitor item Condition Display value
4WD W/LIgnition switch ON ON
Start engine (after several seconds) OFF
SDIA2065E

TROUBLE DIAGNOSIS FOR SYMPTOMS
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Revision: 2007 April2007 M35/M45
4. CHECK AWD CONTROL UNIT
Check AWD control unit input/output signal. Refer to TF-20, "
AWD Control Unit Input/Output Signal Reference
Va l u e s" .
OK or NG
OK >> GO TO 5.
NG >> Check AWD control unit pin terminals for damage or loose connection with harness connector. If
any items are damaged, repair or replace damaged parts.
5. CHECK OUTPUT SIGNAL WITH UNIFIED METER AND A/C AMP.
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “METER A/C AMP” with CONSULT-II.
3. Start the engine, and then make sure that “4WD W/L” display
turns from "ON" to "OFF" after several seconds.
OK or NG
OK >> GO TO 6.
NG >> Perform trouble diagnosis for combination meter. Refer
to DI-18, "
Trouble Diagnosis" .
6. SYMPTOM CHECK
Check again.
OK or NG
OK >>INSPECTION END
NG >> Replace unified meter control unit assembly. Refer to DI-27, "
Disassembly and Assembly of Com-
bination Meter" .
Heavy Tight-Corner Braking Symptom Occurs When The Vehicle Is Driven and
The Steering Wheel Is Turned Fully to Either Side after The Engine Is Started
NDS000DW
NOTE:
Light tight-corner braking symptom may occur depending on driving conditions. This is not malfunc-
tion.
DIAGNOSTIC PROCEDURE
1. CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to TF-22, "
SELF-DIAG RESULT MODE" .
Is the
“CAN COMM CIRCUIT [U1000]” displayed?
YES >> Perform trouble diagnosis for CAN communication line. Refer to TF-32, "CAN Communication
Line" .
NO >> GO TO 2.
2. CHECK ACCELERATOR PEDAL POSITION SIGNAL CIRCUIT
Perform self-diagnosis for ECM. Refer to EC-55, "
Emission-Related Diagnostic Information" .
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 3.
Monitor item Condition Display value
4WD W/LIgnition switch ON ON
Start engine (after several seconds) OFF
SDIA2065E