Diagnostic Procedure

1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check voltage between ECM terminal 121 and ground with CONSULT-III or tester.

   Voltage: Battery voltage 

Fig 1: Checking Voltage Between ECM Terminal 121 And Ground
Courtesy of NISSAN MOTOR CO., U.S.A.

OK or NG 

OK: GO TO  3.

NG: GO TO  2.

Check the following.

• Harness connectors E131, M92
• IPDM E/R connector E124
• 15A fuse
• Harness for open or short between ECM and battery

>> Repair or replace harness or connectors.

Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ."

OK or NG 

OK: GO TO  4.

NG: Repair or replace harness or connectors.

With CONSULT-III 

1. Turn ignition switch ON.
2. Select "SELF DIAG RESULTS" mode with CONSULT-III.
3. Touch "ERASE".
4. Perform DTC Confirmation Procedure  .

   See "DTC CONFIRMATION PROCEDURE ."

5. Is the 1st trip DTC P0603 displayed again?

With GST 

1. Turn ignition switch ON.
2. Select Service $04 with GST.
3. Perform DTC Confirmation Procedure  .

   See "DTC CONFIRMATION PROCEDURE ."

4. Is the 1st trip DTC P0603 displayed again?

Yes or No 

YES: GO TO  5.

NO: INSPECTION END 

1. Replace ECM.
2. Perform initialization of NVIS (NATS) system and registration of all NVIS (NATS) ignition key IDs. Refer to "ECM RE-COMMUNICATING FUNCTION ."
3. Perform "VIN REGISTRATION ."
4. Perform "ACCELERATOR PEDAL RELEASED POSITION LEARNING ."
5. Perform "THROTTLE VALVE CLOSED POSITION LEARNING ."
6. Perform "IDLE AIR VOLUME LEARNING ."

>> INSPECTION END