P0172

DTC P0171 / P0172: Fuel System Too Lean / Rich (Bank-1)

DTC Detecting Condition and Trouble Area






DTC Confirmation Procedure

WARNING:

- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and tester, on a level road.

NOTE:

Check to make sure that the following conditions are satisfied when using this DTC confirmation procedure.

- Intake air temp.: between -10 °C and 60 °C (14 °F and 140 °F)
- Altitude (barometric pressure): 2020 m, 6650 ft or less (540 mmHg, 72 kPa or more)

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature.
4) Operate vehicle within freeze frame data condition as noted for 5 min.
5) Stop vehicle and check DTC and pending DTC.

DTC Troubleshooting

1.
Was "Engine System Check" performed?
YES
Go to Step 2.
NO
Go to Engine System Check Engine System Check.

2.
Is there DTC(s) other than "P0171" and "P0172"?
YES
Go to applicable DTC flow.
NO
Go to Step 3.

3. Check intake system and exhaust system for leakage.

Are intake system and exhaust system in good condition?
YES
Go to Step 4.
NO
Repair or replace.

4. Check fuel pressure.

Check fuel pressure referring to Fuel Pressure Check Fuel Pressure Check.

Is check result satisfactory?
YES
Go to Step 5.
NO
Repair or replace.

5. Check fuel injector.

Check fuel injectors referring to Fuel Injector Inspection Fuel Injector Inspection.

Is check result satisfactory?
YES
Go to Step 6.
NO
Faulty injector(s) or its circuit.

6. Check fuel level sensor.

Check fuel level sensor referring to Step 2 of P0461 DTC P0461: Fuel Level Sensor (Gauge) Circuit Performance Problem.

Is check result satisfactory?
YES
Go to Step 7.
NO
Faulty fuel level sensor or its circuit.

7. Check MAF sensor.

Check MAF sensor referring to Step 2 and 3 of P0101 DTC P0101: Mass Air Flow (MAF) Circuit Performance Problem.

Is check result satisfactory?
YES
Go to Step 8.
NO
Faulty MAF sensor or its circuit.

8. Check ECT sensor.

Check ECT sensor referring to Step 4 and 5 of P0116 DTC P0116: Engine Coolant Temp. (ECT) Circuit Range / Performance Problem.

Is check result satisfactory?
YES
Go to Step 9.
NO
Faulty ECT sensor or its circuit.

9. Check HO2S-1.

Check HO2S-1 referring to Step 2 of P0131 DTC P0131 / P0132: Heated Oxygen Sensor (HO2S) Circuit Low / High Voltage (Bank-1 Sensor-1).

Is check result satisfactory?
YES
Substitute a known-good ECM and recheck.
NO
Faulty HO2S-1 or its circuit.