Code No. P1276: Fuel Filter Exchange <Except vehicles for Thailand>

OPERATION

The battery voltage is applied to the fuel filter pressure switch terminal from the engine-ECU connector terminal FFPS.

FUNCTION

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

TROUBLE JUDGEMENT

Check Condition

During steady driving after engine warm up.

Judgement Criterion

Determination of clogged fuel filter.

FAIL-SAFE AND BACKUP FUNCTION

None

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. Check the fuel filter pressure switch itself.

Check the fuel filter pressure switch itself (Refer to GROUP 13D - Fuel Filter - Fuel Filter Inspection

).

Q. Is the check result normal?

	Go to Step 2.

	Repair or replace the connector, or replace the fuel filter body.

STEP 2. Perform voltage measurement at fuel filter pressure switch connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Voltage between terminal engine-ECU FFPS line and body earth.

OK: System voltage

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Check harness between fuel filter pressure switch connector terminal and engine-ECU connector terminal FFPS.

Check output line for open/short circuit.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 4. M.U.T.-III diagnosis code

Reconfirmation of diagnosis code

Q. Is the diagnosis code set?

	Replace the engine-ECU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 5. Perform resistance measurement at fuel filter pressure switch connector.

Disconnect connector, and measure at harness side.
Resistance between terminal earth line and body earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 4.

	Go to Step 6.

STEP 6. Check harness between fuel filter pressure switch connector terminal and engine-ECU connector terminal FFPS.

Check output line for damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.