Diagnosis Procedure

ECM sends engine speed signal to power steering control unit.

1. PERFORM ECM SELF-DIAGNOSIS 

   With CONSULT

   1. Turn the ignition switch ON.
      CAUTION: Never start the engine
   2. Perform "ENGINE" self-diagnosis. Refer to Diagnosis Description .

   Is any DTC detected?

   YES

   Check the DTC.

   NO

   GO TO 2.

2. CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT 
   1. Turn the ignition switch OFF.
   2. Disconnect ECM harness connectors.
   3. Disconnect power steering control unit harness connector.
   4. Check the continuity between ECM harness connector and power steering control unit harness connector.

      ECM		Power steering control unit		Continuity
      Connector	Terminal	Connector	Terminal
      M107	110	M108	10	Existed

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

      Power steering control unit		--	Continuity
      Connector	Terminal
      M108	10	Ground	Not existed

   Is the inspection result normal?

   YES

   GO TO 3.

   NO

   Repair or replace error-detected parts.

3. CHECK ENGINE SPEED SIGNAL (1) 
   1. Connect ECM harness connectors.
   2. Turn the ignition switch ON.
   3. Check the signal between ECM harness connector and ground with oscilloscope.

      ECM		--	Condition		Voltage (Approx.)
      Connector	Terminal
      M107	110	Ground	Engine is running Warm-up condition Idle speed		Courtesy of NISSAN NORTH AMERICA, INC.
      			Engine is running Warm-up condition Engine speed: Approx. 2, 000 rpm		Courtesy of NISSAN NORTH AMERICA, INC.

   Is the inspection result normal?

   YES

   GO TO 4.

   NO

   Replace ECM. Refer to Work Procedure .

4. CHECK ENGINE SPEED SIGNAL (2) 
   1. Turn the ignition switch OFF.
   2. Connect power steering control unit harness connector.
   3. Check the signal between power steering control unit harness connector and ground with oscilloscope.

   Power steering control unit		--	Condition		Voltage (Approx.)
   Connector	Terminal
   M108	10	Ground	Engine is running Warm-up condition Idle speed		Courtesy of NISSAN NORTH AMERICA, INC.
   			Engine is running Warm-up condition Engine speed: Approx. 2, 000 rpm		Courtesy of NISSAN NORTH AMERICA, INC.

   Is the inspection result normal?

   YES

   GO TO 5.

   NO

   Replace power steering control unit. Refer to POWER STEERING CONTROL UNIT : Removal & Installation .

5. CHECK TERMINALS AND HARNESS CONNECTORS 
   • Check the power steering control unit pin terminals for damage or loose connection with harness connector.
   • Check the ECM pin terminals for damage or loose connection with harness connector.

   Is the inspection result normal?

   YES

   INSPECTION END

   NO

   Repair or replace error-detected parts.