Posted in Mitsubishi Colt

P0203 – No. 3 Injector System MMC Colt

 Posted by  Posted on September 26, 2020

OPERATION

  • Power is supplied to the No. 3 injector (terminal No. 1) from the engine control relay (terminal No. 4).
  • The engine-ECU (terminal No. 23) makes the power transistor in the unit be in “ON” position, and that makes currents go on the No. 3 injector (terminal No. 2).

    • FUNCTION

  • The engine-ECU controls the power supply interval of the No. 3 injector.
  • The fuel injection amount of the No. 3 injector depends on the power supply interval.

    • TROUBLE JUDGMENT

  • While engine is running.
  • Injector coil surge voltage (battery positive voltage + 2 V) has not been detected for 2 seconds.

    • PROBABLE CAUSES

  • Failed No. 3 injector
  • Open or shorted No. 3 injector circuit, harness damage, or connector damage
  • Failed engine-ECU

    • DIAGNOSIS PROCEDURE

    STEP 1. M.U.T.-III actuator test

  • Item No. 3: No. 3 injector

    • Q. Is the check result normal?

    STEP 2. Connector check: A-123 No. 3 injector connector

    Q. Is the check result normal?

    STEP 3. Check No. 3 injector itself.

    Q. Is the check result normal?

    STEP 4. Perform voltage measurement at A-123 No. 3 injector connector.

  • Disconnect connector, and measure at harness 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. Connector check: B-206 engine control relay connector

    Q. Is the check result normal?

    STEP 7. Check harness between B-206 (terminal No. 4) engine control relay connector and A-123 (terminal No. 1) No. 3 injector connector.

  • Check power supply line for damage.

    • Q. Is the check result normal?

    STEP 8. Connector check: A-08 engine-ECU connector

    Q. Is the check result normal?

    STEP 9. Check harness between A-123 (terminal No. 2) No. 3 injector connector and A-08 (terminal No. 23) engine-ECU connector.

  • Check earthing line for open/short circuit and damage.

    • Q. Is the check result normal?

    STEP 10. Perform signal wave pattern measurement at A-08 engine-ECU connector (Using on oscilloscope).

  • Disconnect engine-ECU connector, and connect special tool power plant ECU check harness (MB991987), and then measure the voltage on the check connector.
  • Engine: Idling
  • Transmission: Neutral
  • Voltage between terminal No. 23 and earth.

    • Q. Is the check result normal?

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