Posted in Mitsubishi Colt

DTC P0657 – ThrottleValve Control Servo Relay Circuit Malfunction MMC Colt

 Posted by  Posted on September 26, 2020

OPERATION

  • Battery voltage is applied to the throttle valve control servo relay terminal (terminal No. 3).
  • Battery voltage is applied to the throttle valve control servo relay terminal (terminal No. 1) from the engine control relay (terminal No. 4).
  • Engine-ECU (terminal No. 123) applies current to the throttle valve control servo relay coil by turning ON the power transistor in the unit in order to turn the relay ON.
  • When the throttle valve control servo relay turns ON, battery voltage is supplied by the throttle valve control servo relay (terminal No. 4) to the engine-ECU (terminal No. 78).

    • FUNCTION

  • When the ignition switch ON signal is input into the engine-ECU, the engine-ECU turns ON the Throttle valve control servo.

    • TROUBLE JUDGMENT

  • After engine starting sequence is completed.
  • The power line voltage of the electronic controlled throttle system is 4.0 V or less for 1 second.

    • PROBALE CAUSES

  • Failed throttle valve return spring
  • Open or shorted throttle valve control servo relay circuit, harness damage, or connector damage
  • Failed engine-ECU

    • DIAGNOSIS

    STEP 1. Connector check: B-221 throttle valve control servo relay connector

    Q. Is the check result normal?

    STEP 2. Check throttle valve control servo relay itself.

    Q. Is the check result normal?

    STEP 3. Perform voltage measurement at B-221 throttle valve control servo relay connector.

  • Remove relay, and measure at J/B side.
  • Voltage between terminal No. 3 and earth.

    • Q. Is the check result normal?

  • Check power supply line for open/short circuit.

    • STEP 4. Perform voltage measurement at B-221 throttle valve control servo relay connector.

  • Remove relay, and measure at J/B side.
  • Ignition switch: ON
  • Voltage between terminal No. 1 and earth.

    • Q. Is the check result normal?

    STEP 5. Connector check: B-206 engine control relay connector

    Q. Is the check result normal?

  • Check power supply line for open/short circuit.

    • STEP 6. Perform voltage measurement at A-09 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 123 and earth.

    • Q. Is the check result normal?

  • Check earthing line for open/short circuit.

    • STEP 7. Perform voltage measurement at A-09 engine-ECU connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Using a jumper wire, connect A-09 (terminal No. 123) engine-ECU connector and earth.
  • Voltage between terminal No. 78 and earth.

    • Q. Is the check result normal?

    STEP 8. Check harness between B-221 (terminal No. 4) throttle valve control servo relay connector and A-09 (terminal No. 78) engine-ECU connector.

  • Check power supply line for open/short circuit.

    • Q. Is the check result normal?

    STEP 9. Connector check: A-09 engine-ECU connector

    Q. Is the check result normal?

    STEP 10. Connector check: A-09 engine-ECU connector

    Q. Is the check result normal?

    STEP 11. Check and repair harness between B-221 (terminal No. 3) throttle valve control servo relay connector and battery.

  • Check power supply line for damage.

    • Q. Is the harness connector in good condition?

    STEP 12. Check and repair harness between B-221 (terminal No. 1) throttle valve control servo relay connector and B-206 (terminal No. 4) engine control relay connector.

  • Check power supply line for damage.

    • Q. Is the harness connector in good condition?

    STEP 13. Check and repair harness between B-221 (terminal No. 2) throttle valve control servo relay connector and A-09 (terminal No. 123) engine-ECU connector.

  • Check power supply line for damage.

    • Q. Is the harness connector in good condition?

    STEP 14. Check and repair harness between B-221 (terminal No. 4) throttle valve control servo relay connector and A-09 (terminal No. 78) engine-ECU connector.

  • Check power supply line for damage.

    • Q. Is the harness connector in good condition?

    STEP 15. M.U.T.-III diagnosis code

  • Reconfirmation of diagnosis code.

    • Q. Is the diagnosis code set?

    Author: admin