Diagnosis Procedure

PERFORM ECM SELF-DIAGNOSIS
With CONSULT

Perform self-diagnosis for "ENGINE".

Is any error system detected?

YES

Check the DTC.
- VQ37VHR FOR USA AND CANADA: Refer to DTC Index .
- VK56VD FOR USA AND CANADA: Refer to DTC Index .
NO

GO TO 2.

CHECK ENGINE SPEED SIGNAL CIRCUIT

Turn the ignition switch OFF.
Disconnect ECM harness connectors.
Disconnect power steering control unit harness connector.

Check the continuity between ECM harness connector and power steering control unit harness connector.

Power steering control unit

ECM

Continuity

Connector

Terminal

Connector

Terminal

M108

M107 ^*1

M124 ^*2

M56 ^*3

M160 ^*4

110 ^*1

126 ^{*2, 3}

169 ^*4

Existed

*1: VQ37VHR (Without EVAP control system)

*2: VQ37VHR (With EVAP control system)

*3: VK56VD(Except for Mexico)

*4: VK56VD(For Mexico)

Is the inspection result normal?

YES

GO TO 3.

Repair or replace damaged parts.

CHECK ENGINE SPEED SIGNAL (ECM)

Connect ECM harness connectors.

Check the signal between ECM harness connector and ground with oscilloscope.

ECM		--	Condition	Value (Approx.)
Connector	Terminal
M107 ^1 M124 ^2 M56 ^3 M160 ^4	110 ^1 126 ^{2, 3} 169 ^*4	Ground	Engine speed: At idle (Warm-up condition)	VQ37VHR Courtesy of NISSAN NORTH AMERICA, INC.
				VK56VD Courtesy of NISSAN NORTH AMERICA, INC.
			Engine speed: Approx. 2, 000 RPM (Warm-up condition)	VQ37VHR Courtesy of NISSAN NORTH AMERICA, INC.
				VK56VD Courtesy of NISSAN NORTH AMERICA, INC.

*1: VQ37VHR (Without EVAP control system)

*2: VQ37VHR (With EVAP control system)

*3: VK56VD(Except for Mexico)

*4: VK56VD(For Mexico)

Is the inspection result normal?

YES

GO TO 4.

Replace ECM.

VQ37VHR FOR USA AND CANADA: Refer to Description .
VK56VD FOR USA AND CANADA: Refer to Description .

CHECK ENGINE SPEED SIGNAL (POWER STEERING CONTROL UNIT)

Turn the ignition switch OFF.
Connect power steering control unit harness connector.

Check the signal between power steering control unit harness connector and ground with oscilloscope.

Power steering control unit		--	Condition	Value (Approx.)
Connector	Terminal
M108	10	Ground	Engine speed: At idle (Warm-up condition)	VQ37VHR Courtesy of NISSAN NORTH AMERICA, INC.
				VK56VD Courtesy of NISSAN NORTH AMERICA, INC.
			Engine speed: Approx. 2, 000 RPM (Warm-up condition)	VQ37VHR Courtesy of NISSAN NORTH AMERICA, INC.
				VK56VD Courtesy of NISSAN NORTH AMERICA, INC.

Is the inspection result normal?

YES

GO TO 5.

Replace power steering control unit. Refer to Removal and Installation .

CHECK TERMINALS AND HARNESS CONNECTORS
- Check the power steering control unit pin terminals for damage or loose connection with harness connector.
- Check ECM pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?

YES

INSPECTION END

NO

Repair or replace damaged parts.