Nissan Versa (N17): P0603 ECM power supply

Description

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

Power supply

DTC Logic

DTC DETECTION LOGIC

DTC No. Trouble diagnosis DTC detecting condition Possible cause

P0603

ECM BACK UP/CIRCUIT (ECM power supply circuit) ECM back-up RAM system does not function properly.
  • Harness or connectors [ECM power supply (back up) circuit is open or shorted.]
  • ECM

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

  1. Turn ignition switch OFF and wait at least 10 seconds.
  2. Turn ignition switch ON.
  3. Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

2.PERFORM DTC CONFIRMATION PROCEDURE

  1. Turn ignition switch ON wait at least 10 seconds.
  2. Turn ignition switch OFF and wait at least 5 minutes
  3. Turn ignition switch ON, wait at least 10 seconds.
  4. Repeat step 2 and 3 for five times.
  5. Check 1st trip DTC.

Is 1st trip DTC detected?

YES >> Go to EC, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.INSPECTION START

  1. Erase DTC.
  2. Perform DTC CONFIRMATION PROCEDURE.

Is the 1st trip DTC P0603 displayed again?

YES >> GO TO 2.

NO >> INSPECTION END

2.REPLACE ECM

  1. Replace ECM. Refer to EC, "Removal and Installation".
  2. Perform EC, "Work Procedure".

>> INSPECTION END

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