P0603

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
1. If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and let it idle for 1 second.
3. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
4. Repeat steps 1 and 2 for 4 times.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to SEE Diagnosis Procedure.




Diagnosis Procedure
1.CHECK ECM POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.





3. Check voltage between ECM terminal 121 and ground with
CONSULT-III or tester.





OK or NG
OK - GO TO 3.
NG - GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
- IPDM E/R connector E121
- 20A fuse
- Harness for open or short between ECM and battery
- Repair or replace harness or connectors.
3.CHECK INTERMITTENT INCIDENT
How to Check Terminal and Intermittent Incident.
OK or NG
OK - GO TO 4.
NG - Repair or replace harness or connectors.
4.PERFORM DTC CONFIRMATION PROCEDURE
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 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 SEE DTC Confirmation Procedure.
4. 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. Special Repair Requirement With Intelligent Key System (With intelligent key system) or Special Repair Requirement Without Intelligent Key System (Without intelligent key system).
3. Perform VIN Registration.
4. Perform Accelerator Pedal Released Position Learning.
5. Perform Throttle Valve Closed Position Learning.
6. [Flexible Fuel Vehicle]
Perform Ethanol Mixture Ratio Adaptation (Flexible Fuel Vehicle).
7. Perform Idle Air Volume Learning.
- INSPECTION END