P0603

DTC P0603 ECM POWER SUPPLY





Component Description





Battery voltage is supplied to the ECM even when the ignition switch is turned OFF for the ECM memory function of the DTC memory, the air-fuel ratio feedback compensation value memory, the Idle Air Volume Learning value memory, etc.




On Board Diagnosis Logic









DTC Confirmation Procedure

NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
1. Turn ignition switch ON and wait at least 10 seconds.
2. Turn ignition switch OFF and wait at least 5 minutes.
3. Turn ignition switch ON and wait at least 10 seconds.
4. Repeat steps 2 and 3 for five times.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to P0603.




Wiring Diagram

EC-PCM/PW-01:

Specification data are reference values and are measured between each terminal and ground.

CAUTION:
Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.









Diagnosis Procedure
1.CHECK ECM POWER SUPPLY
1. Turn ignition switch OFF.





2. Check voltage between ECM terminal and ground with CONSULT-III or tester.

Voltage: Battery voltage

OK or NG
OK - GO TO 3.
NG - GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E17, F10
- 20 A fuse
- Harness for open or short between ECM and battery
- Repair open circuit or short to ground or short to power in harness or connectors.
3.CHECK INTERMITTENT INCIDENT
Description Diagnosis Procedure.
OK or NG
OK - GO TO 4.
NG - Repair or replace harness or connectors.
4.PERFORM DTC CONFIRMATION PROCEDURE
1. Erase DTC.
2. Perform DTC Confirmation Procedure.
See P0603.
3. Is the 1st trip DTC P0603 displayed again?
Yes or No
Yes - GO TO 5.
No - INSPECTION END
5.REPLACE ECM
1. Replace ECM.
2. Perform initialization of NVIS (NATS) system and registration of all NVIS (NATS) ignition key IDs. NATS (Nissan Anti-Theft System) System Description.
3. Perform Testing and Inspection.
4. Perform Testing and Inspection.
5. Perform Throttle Valve Closed Position Learning.
6. Perform Programming and Relearning.
- INSPECTION END