P0172
DTC P0171: Fuel System Too LeanDTC P0172: Fuel System Too Rich
NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
- If some of the DTCs listed below are indicated at the same time as DTC P0171 and/or P0172, troubleshoot those DTCs first, then recheck for P0171 and/or P0172.
P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor
P0133, P1172 (2005-2006 models), P1157, P2195, P2238,
P2252, P2AOO: Air fuel ratio (A/F) sensor (Sensor 1)
P0134, P0135: Air fuel ratio (A/F) sensor (Sensor 1) heater
P0137, P0138, P0139, P2270 (2005-2006 models), P2271 (2005-2006 models): Secondary HO2S (Sensor 2)
P0141: Secondary HO2S (Sensor 2) heater
P2646, P2647, P2648, P2649: VTEC system
P2279: Intake air leakage
1. Check the fuel pressure.
Is the fuel pressure OK?
YES - Check the engine valve clearances and adjust if necessary (P0172 only). If the valve clearances are OK, replace the injectors, then go to step 2.
N0-
- If the pressure is too high, replace the fuel pressure regulator, then go to step 2.
- If the pressure is too low, check the fuel pump and the fuel feed line. Then go to step 2.
2. Turn the ignition switch ON (II).
3. Reset the ECM/PCM with the HDS.
4. Do the ECM/PCM idle learn procedure
5. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
6. Test-drive under these conditions:
- ECT SENSOR (2004-2005 models), ECT SENSOR 1 (2006 model) above 176 degrees F (80 degrees C)
- M/T in neutral (A/T in Park or neutral)
- All electric loads off
NOTE: DTC P0171 and/or P0172 may take up to 80 minutes of test driving to set. Using the HDS, monitor the long term fuel trim (LT FUEL TRIM) or the air fuel feed back average (AF FB AVE). If the long term fuel trim/air fuel feed back average stays within 0.80-1.20, there is no problem at this time.
7. Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated7
YES - If DTC P0171 or P0172 is indicated, go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO - Troubleshooting is complete.