Code No. P0172: Abnormal Fuel System (rich)


OPERATION



  • Check code No. P0261: No. 1 injector circuit low input (Refer to ).
  • Check code No. P0262: No. 1 injector circuit high input (Refer to ).
  • Check code No. P0264: No. 2 injector circuit low input (Refer to ).
  • Check code No. P0265: No. 2 injector circuit high input (Refer to ).
  • Check code No. P0267: No. 3 injector circuit low input (Refer to ).
  • Check code No. P0268: No. 3 injector circuit high input (Refer to ).
  • Check code No. P0270: No. 4 injector circuit low input (Refer to ).
  • Check code No. P0271: No. 4 injector circuit high input (Refer to ).

FUNCTION



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

TROUBLE JUDGMENT


Check Conditions
  • Under the closed loop air/fuel ratio control.
  • Engine coolant temperature is more than 76°C.
Judgement Criterion
  • Long-term fuel trim is less than -12.5 % for 5 seconds.


  • Short-term fuel trim is less than -10.2 % for 5 seconds.
Check Conditions
  • Engine coolant temperature is more than 76°C.
  • Under the closed loop air/fuel ratio control.
Judgement Criterion
  • Long-term fuel trim is -12.5 % for 2 seconds.


  • Short-term fuel trim is -25.0 % for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION



  • None

PROBABLE CAUSES



  • Failed intake air temperature sensor
  • Failed air flow sensor
  • Failed injector
  • Failed engine coolant temperature sensor
  • Failed manifold absolute pressure sensor
  • Failed barometric pressure sensor
  • Incorrect fuel pressure
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

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

Q. Is any other diagnosis code than P0172 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 injector itself.

  • Injector check (Refer to ).

Q. Is the check result normal?
Go to Step 4.
Replace the injector.

STEP 4. Fuel pressure measurement.

  • Fuel pressure test (Refer to ).

Q. Is the check result normal?
Go to Step 5.
Repair.

STEP 5. 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.