Posted in Mitsubishi Colt

P1603 – Battery Backup Circuit Malfunction MMC Colt

 Posted by  Posted on September 26, 2020

OPERATION

  • Power is directly supplied to the engine-ECU (terminal No. 82) from the battery.

    • FUNCTION

  • The engine-ECU is check the open circuit of battery backup line.

    • TROUBLE JUDGMENT

  • After engine starting sequence is completed.
  • Battery positive voltage is 10 V or higher.
  • Battery backup line voltage is 6 V or lower for 2 seconds.

    • PROBABLE CAUSES

  • Open or shorted battery back up circuit, harness damage, or connector damage
  • Failed engine-ECU

    • DIAGNOSIS PROCEDURE

    STEP 1. M.U.T.-III diagnosis code

  • Temporarily place the ignition switch in “LOCK” (OFF) position, and 10 seconds after that, place it in “ON” position again.

    • Q. Is the diagnosis code P1603 set?

    STEP 2. Perform voltage measurement at A-09 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 82 and earth.

    • Q. Is the check result normal?

  • Check power supply line for open/short circuit.

    • STEP 3. Check harness between battery and A-09 (terminal No. 82) engine-ECU connector.

  • Check power supply line for damage.

    • Q. Is the check result normal?

    STEP 4. Connector check: A-09 engine-ECU connector

    Q. Is the check result normal?

    STEP 5. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

    • Q. Is the diagnosis code set?

    Author: admin