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. Start engine and let it idle for 1 second.
2. Turn ignition switch OFF, wait at least 10 seconds, and then turn ON.
3. Repeat steps 1 and 2 for four times.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to "Diagnosis Procedure".




Wiring Diagram





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

CAUTION:
Do not 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 66 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
- 20A fuse
- Harness for open or short between ECM and battery
>> Repair or replace harness or connectors.
3.CHECK INTERMITTENT INCIDENT
Refer to For California For California.
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 "DTC Confirmation Procedure".
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. Refer to Programming and Relearning.
3. Perform For California.
4. Perform For California.
5. Perform For California.
6. Perform For California.
>> INSPECTION END