Code No. P0171: Abnormal Fuel System (lean)




OPERATION




FUNCTION




TROUBLE JUDGMENT


Check Conditions
Judgement Criterion
or

Check Conditions
Judgement Criterion
or

Check Conditions
Judgement Criterion
or


FAIL-SAFE AND BACKUP FUNCTION




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


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


Q. Is any other diagnosis code than P0171 set?

Inspection chart for diagnosis code (Refer to ).
Go to Step 2.

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



  • Data list reference table (Refer to ).

  1. Item 5: Intake air temperature sensor
  2. Item 6: Engine coolant temperature sensor
  3. Item 8: Manifold absolute pressure sensor
  4. Item 10: Air flow sensor
  5. Item BB: Barometric pressure sensor

Q. Are the check results normal?

YES : Go to Step 3.
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value. Inspection chart for diagnosis code (Refer to ).

STEP 3. Check for exhaust leaks


Q. Is the check result normal?

Go to Step 4.
Repair.

STEP 4. Check for intake system vacuum leaks.


Q. Is the check result normal?

Go to Step 5.
Repair.

STEP 5. Check injector itself.



  • No. 1, No. 2, No. 3 and No. 4 injector connector check.
  • Injector check (Refer to ).

Q. Is the check result normal?

Go to Step 6.
Repair or replace the connector, or replace the injector.

STEP 6. Check harness between injector connector and engine-ECU connector.



  1. Check and repair harness between No. 1 injector connector terminal and engine-ECU connector terminal INJ1.
  2. Check and repair harness between No. 2 injector connector terminal and engine-ECU connector terminal INJ2.
  3. Check and repair harness between No. 3 injector connector terminal and engine-ECU connector terminal INJ3.
  4. Check and repair harness between No. 4 injector connector terminal and engine-ECU connector terminal INJ4.

  • Check output line for damage.

Q. Are the check results normal?

Go to Step 7.
Repair or replace the connector, or repair the damaged harness wire.

STEP 7. Fuel pressure measurement.



  • Fuel pressure test (Refer to ).

Q. Is the check result normal?

Go to Step 8.
Repair.

STEP 8. Check fuel.



  • Check for entry of foreign matter (water, diesel fuel, etc.) into fuel.

Q. Is the check result normal?

Go to Step 9.
Replace the fuel.

STEP 9. Replace the injector.



  • After replacing the injector, reconfirm whether the diagnosis code is set.

Q. Is the diagnosis code set?

Replace the engine-ECU.
Check end.