Infiniti Q45. Manual - part 880

TROUBLE DIAGNOSIS FOR SYSTEM

STC-23

[WITHOUT REAR ACTIVE STEER]

C

D

E

F

H

I

J

K

L

M

A

B

STC

3. 

CHECK POWER STEERING SOLENOID VALVE

1.

Turn ignition switch “OFF”.

2.

Disconnect power steering solenoid valve harness connector.

3.

Check resistance between power steering solenoid valve con-
nector (A) terminals 1 and 2.

4.

Check power steering solenoid valve connector (A) by listening
for its operation sound while applying battery voltage to power
steering solenoid valve connector (A) terminals 1 (positive) and
2 (negative).

 OK or NG

 OK 

>> GO TO 4.

 NG

>> Replace power steering solenoid valve. Refer to 

PS-17,

"Disassembly and Assembly"

 .

4. 

CHECK HARNESS BETWEEN ACTIVE DAMPER SUSPENSION CONTROL UNIT AND POWER 

STEERING SOLENOID VALVE

1.

Turn ignition switch “OFF”.

2.

Disconnect active damper suspension control unit harness connector and power steering solenoid valve
harness connector.

3.

Check continuity between active damper suspension control unit
harness connector (A) B37 terminal 21 and power steering sole-
noid valve harness connector (B) F3 terminal 1.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 5.

NG

>> Repair or replace damaged parts.

5. 

CHECK ACTIVE DAMPER SUSPENSION CONTROL UNIT

Check active damper suspension control unit input/output signal. Refer to 

STC-12, "Active Damper Suspen-

sion Control Unit Input/Output Signal Reference Values"

 .

OK or NG

OK

>> GO TO 6.

NG

>> Check active damper suspension control unit pin terminals for damage or loose connection with

harness connector. If any item is damaged, repair or replace damaged parts.

1 - 2

: Approx. 4 - 6 

Ω

SGIA1412E

SGIA1419E

Continuity should exist.

SGIA1413E

STC-24

[WITHOUT REAR ACTIVE STEER]

TROUBLE DIAGNOSIS FOR SYSTEM

6. 

STEERING WHEEL TURNING FORCE INSPECTION

Check steering wheel turning force. Refer to 

PS-8, "STEERING WHEEL TURNING FORCE"

 .

OK or NG

OK

>> INSPECTION END

NG

>> Check relief oil pressure of power steering oil pump and power steering gear. If any item is dam-

aged, repair or replace damaged parts. Refer to 

PS-26, "RELIEF OIL PRESSURE"

  (power steer-

ing oil pump) and 

PS-17, "Disassembly and Assembly"

  (power steering gear).

Engine Speed Signal

NGS0006A

●

Check the following if “flickering pattern for 31” is detected in self-diagnosis results without CONSULT-II.

CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE

Data are reference value.

ACTIVE DAMPER SUSPENSION CONTROL UNIT TERMINALS AND REFERENCE VALUE

Data are reference value and are measured between each terminal and ground.

CAUTION:

When using a oscilloscope to measure voltage for inspection, be sure not to extend forcibly any connector terminal.

DIAGNOSTIC PROCEDURE

1. 

CHECK DTC WITH ECM

Perform self-diagnosis with ECM. Refer to 

EC-118, "SELF-DIAG RESULTS MODE"

 .

Is any malfunction detected by self-diagnosis?

YES

>> Check the malfunctioning system.

NO

>> GO TO 2.

Monitored item

Content

Condition

Display value

ENGINE SPEED [rpm]

Engine speed

Engine stopped

0 rpm

Engine running
(Engine speed: 400 rpm or more)

Approximately 
equal to the indica-
tion on tachometer

Terminal

Wire 

color

Item

Condition

Data (Approx.)

12

W/G

Engine speed

Engine speed: At idle
(Warm-up condition)

Engine speed: Approx. 2,000 rpm
(Warm-up condition)

PBIA3654J

PBIA3655J

TROUBLE DIAGNOSIS FOR SYSTEM

STC-25

[WITHOUT REAR ACTIVE STEER]

C

D

E

F

H

I

J

K

L

M

A

B

STC

2. 

CHECK ENGINE SPEED SIGNAL

 With CONSULT-II

1.

Start engine.

2.

Select “DATA MONITOR” mode for “ACT D/SUS” with CONSULT-II.

3.

Read out the value of “ENGINE SPEED”.

 Without CONSULT-II

1.

Start engine.

2.

Check signal between active damper suspension control unit
harness connector (A) terminal and ground with oscilloscope.

Also check harness for short to ground and short to power.

OK or NG

YES

>> GO TO 4.

NO

>> GO TO 3.

Condition

Display value

Engine stopped

0 rpm

Engine running
(Engine speed: 400 rpm or more)

Approximately 
equal to the indica-
tion on tachometer

SEIA0779E

Connector

Terminal

Condition

Data (Approx.)

B37

 12 - 

Ground

Engine speed: At idle
(Warm-up condition)

Engine speed: 
Approx. 2,000 rpm
(Warm-up condition)

SEIA0780E

PBIA3654J

PBIA3655J

STC-26

[WITHOUT REAR ACTIVE STEER]

TROUBLE DIAGNOSIS FOR SYSTEM

3. 

CHECK HARNESS BETWEEN ECM AND ACTIVE DAMPER SUSPENSION CONTROL UNIT

1.

Turn ignition switch “OFF”.

2.

Disconnect ECM harness connector and active damper suspension control unit harness connector.

3.

Check continuity between ECM harness connector (A) F101 ter-
minal 103 and active damper suspension control unit harness
connector (B) B37 terminal 12.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace damaged parts.

4. 

CHECK ACTIVE DAMPER SUSPENSION CONTROL UNIT

Check active damper suspension control unit input/output signal. Refer to 

STC-12, "Active Damper Suspen-

sion Control Unit Input/Output Signal Reference Values"

 .

OK or NG

OK

>> GO TO 5.

NG

>> Check active damper suspension control unit pin terminals for damage or loose connection with

harness connector. If any items are damaged, repair or replace damaged parts.

5. 

CHECK DTC

Perform the self-diagnosis, after driving a vehicle for a while.

OK or NG

OK

>> INSPECTION END

NG

>> Perform self-diagnosis with ECM again. Refer to 

EC-118, "SELF-DIAG RESULTS MODE"

 .

Continuity should exist.

SEIA0781E