Nissan Maxima Service and Repair Manual: Engine speed signal circuit

Description

ECM sends engine speed signal to power steering control unit.

Diagnosis Procedure

1.PERFORM ECM SELF-DIAGNOSIS

With CONSULT

Perform ECM self-diagnosis.

2.CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT FOR OPEN

1. Turn the ignition switch OFF.
2. Disconnect ECM connector E10.
3. Disconnect power steering control unit connector.
4. Check continuity between ECM connector E10 (A) terminal 94
   and power steering control unit connector M59 (B) terminal 10.

3.CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT FOR SHORT

1. Check continuity between ECM connector E10 terminal 94 and
   ground.
2. Turn ignition switch ON.
3. Check voltage between ECM connector E10 terminal 94 and
   ground.

4.CHECK ENGINE SPEED SIGNAL (ECM SIDE)

1. Turn the ignition switch OFF.
2. Connect ECM connector E10.
3. Start the engine.
4. Check signal between ECM connector E10 terminal 94 and
   ground with oscilloscope.

5.CHECK ENGINE SPEED SIGNAL (POWER STEERING CONTROL UNIT SIDE)

1. Turn the ignition switch OFF.
2. Connect power steering control unit harness connector.
3. Start the engine.
4. Check signal between power steering control unit harness connector
   M59 terminal 10 and ground with oscilloscope

6.CHECK TERMINALS AND HARNESS CONNECTORS

1. Check power steering control unit pin terminals for damage or loose connection with harness connector.
2. Check ECM pin terminals for damage or loose connection with harness connector.