Code No. P0172: Abnormal Fuel System (rich)




OPERATION



  • Refer to Code No. P0201: No. 1 Injector System .
  • Refer to Code No. P0202: No. 2 Injector System .
  • Refer to Code No. P0203: No. 3 Injector System .
  • Refer to Code No. P0204: No. 4 Injector System .

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.
  • Air flow sensor output is more than 10 g/sec.
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
  • Under the closed loop air/fuel ratio control.
  • Engine coolant temperature is more than 76°C.
  • Air flow sensor output is less than 10 g/sec.
Judgement Criterion
  • Long-term fuel trim is less than -12.5 % for 5 seconds.


  • Short-term fuel trim is less than -15.2 % 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 data list

  • Refer to Data List Reference Table .

  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?
Go to Step 2 .
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 2. Check injector itself.

  • Check Injector itself (Refer to ).

Q. Is the check result normal?
Go to Step 3 .
Replace the injector.

STEP 3. Fuel pressure measurement.

  • Fuel pressure measurement (Refer to Fuel Pressure Test ).

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

STEP 4. 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.