P0170 – Abnormal Fuel System MMC Colt

FUNCTION

  • If the fuel system goes out of order, the fuel correction valve will become larger.
  • The engine-ECU checks whether the fuel trim value is within a specified range.

  • TROUBLE JUDGMENT

  • In learning the air-fuel ratio.
  • Long-term fuel trim has continued to be +12.5% or higher for 10 seconds.
  • Long-term fuel trim has continued to be -12.5% or higher for 10 seconds.

  • PROBABLE CAUSES

  • Failed intake air temperature sensor
  • Failed purge control solenoid valve
  • Failed injector
  • Air drawn in from gaps in gasket, seals, etc.
  • Failed engine coolant temperature sensor
  • Failed manifold absolute pressure sensor
  • Exhaust leak
  • Incorrect fuel pressure
  • Failed engine-ECU
  • Harness damage in injector circuit, or connector damage

  • DIAGNOSIS PROCEDURE

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

    Q. Is any other diagnosis code than P0170 output?

    STEP 2. M.U.T.-III data list

  • Item No. 6: Intake air temperature sensor
  • Item No. 7: Manifold absolute pressure sensor
  • Item No. 8: Engine coolant temperature sensor
  • Q. Are the check results normal?

    STEP 3. Check throttle body (throttle valve portion) for contamination.

    Q. Is the check result normal?

    STEP 4. Check for intake of air from gaps in gasket, seals, etc.

    Q. Is the check result normal?

    STEP 5. Check for leakage of exhaust emission from exhaust manifold.

    Q. Is the check result normal?

    STEP 6. Connector check: Injector connectors

  • A-101 (No. 1 injector connector).
  • A-102 (No. 2 injector connector).
  • A-123 (No. 3 injector connector).
  • Q. Are the check results normal?

    STEP 7. Check injector itself.

    Q. Is the check result normal?

    STEP 8. Connector check: B-206 engine control relay connector and A-08 engine-ECU connector

    Q. Is the check result normal?

    STEP 9. Check harness between B-206 engine control relay connector and injector connectors.

  • Check harness between B-206 (terminal No. 4) engine control relay connector and A-101 (terminal No. 1) No. 1 injector connector.
  • Check harness between B-206 (terminal No. 4) engine control relay connector and A-102 (terminal No. 1) No. 2 injector connector.
  • Check harness between B-206 (terminal No. 4) engine control relay connector and A-123 (terminal No. 1) No. 3 injector connector.
    note Before checking harness, check intermediate connectors A-13 and B-212, and repair if necessary.
  • Check power supply line for damage.
  • Q. Are the check results normal?

    STEP 10. Check harness between injector connectors and A-08 engine-ECU connector.

  • Check harness between A-101 (terminal No. 2) No. 1 injector connector and A-08 (terminal No. 8) engine-ECU connector.
  • Check harness between A-102 (terminal No. 2) No. 2 injector connector and A-08 (terminal No. 9) engine-ECU connector.
  • 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 damage.
  • Q. Are the check results normal?

    STEP 11. Check purge control solenoid valve itself.

    Q. Is the check result normal?

    STEP 12. Fuel pressure measurement.

    Q. Is the check result normal?

    Author: admin