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

P0603:

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 it ON.
4. Repeat steps 2 and 3 for 4 times.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to [P0603 ECM Power Supply].

Diagnosis Procedure

Step 1-3:

Step 4-5: