P1276 – Fuel Filter Exchange Vehicles with fuel filter pressure switch MMC L200 IV



OPERATION

  • The battery voltage is applied to the fuel filter pressure switch (terminal No. 1) from the engine-ECU (terminal No. 110).

  • FUNCTION

  • The engine-ECU detects the clogged fuel filter by using the fuel filter pressure switch installed on the fuel filter assembly.

  • TROUBLE JUDGMENT

  • During steady driving after engine warm up.
  • Determination of clogged fuel filter.

  • PROBABLE CAUSES

  • Failed fuel filter pressure switch
  • Open/short circuit or harness damage in fuel filter pressure switch circuit or loose connector contact
  • Failed engine-ECU

  • DIAGNOSIS PROCEDURE

    STEP 1. Connector check: A-143 fuel filter pressure switch connector

    Q. Is the check result normal?

    STEP 2. Check the fuel filter pressure switch itself.

    Q. Is the check result normal?

    STEP 3. Perform voltage measurement at A-143 fuel filter pressure switch 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 4. Connector check: C-103 engine-ECU connector

    Q. Is the check result normal?

    STEP 5. Check harness between A-143 (terminal No. 1) fuel filter pressure switch connector and C-103 (terminal No. 110) engine-ECU connector.

  • Check output line for open/short circuit.
  • Q. Is the check result normal?

    STEP 6. M.U.T.-III data list

  • Item 152: Fuel filter pressure switch
  • Q. Is the check result normal?

    STEP 7. Perform resistance measurement at A-143 fuel filter pressure switch connector.

  • Disconnect connector, and measure at harness side.
  • Resistance between terminal No. 2 and earth.
  • Q. Is the check result normal?

  • Check earthing line for open circuit and damage.
  • STEP 8. Connector check: C-103 engine-ECU connector

    Q. Is the check result normal?

    STEP 9. Check harness between A-143 (terminal No. 1) fuel filter pressure switch connector and C-103 (terminal No. 110) engine-ECU connector.

  • Check output line for damage.
  • Q. Is the check result normal?

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