DTC P0171, P0172, P0174, P0175: Rear Bank (Bank 1) Fuel System Too Lean; Rear Bank (Bank 1) Fuel System Too Rich; Front Bank (Bank 2) Fuel System Too Lean; Front Bank (Bank 2) Fuel System Too Rich

NOTE:

If some of the DTCs listed below are stored at the same time as DTC P0171, P0172, P0174 and/or P0175, troubleshoot those DTCs first, then recheck for P0171, P0172, P0174 and/or P0175.

P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor

P0133, P0153, P2195, P2197, 2237, P2238, P2240, P2241, P2243, P2245, P2247, P2249, P2251, P2252, P2254, P2255, P2627, P2628, P2630, P2631, P2A00, P2A03: Air fuel ratio (A/F) sensor (Sensor 1)

P0134, P0135, P0154, P0155: Air fuel ratio (A/F) sensor (Sensor 1) heater

P0137, P0138, P0139, P0157, P0158, P0159: Secondary HO2S (Sensor 2)

P0141, P0161: Secondary HO2S (Sensor 2) heater

P2646, P2647, P2648, P2649: VTEC system

P0401, P0404, P0406, P2413: Exhaust gas recirculation (EGR) system

P2279: Intake air leakage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).

Check the fuel pressure (see FUEL PRESSURE TEST ).
Is the fuel pressure OK?
1. YES - Check the valve clearances and adjust if necessary (P0172, P0175 only). If the valve clearances are OK, replace the injectors (see INJECTOR REPLACEMENT ), then go to step 2.
2. NO - Check these items:
  - If the pressure is too high, replace the fuel pressure regulator (see FUEL PRESSURE REGULATOR REPLACEMENT ), then go to step 2. If the pressure is too low, check the fuel pump, the fuel filter, and the fuel feed pipe, then go to step 2.
Turn the ignition switch ON (II).
Reset the PCM with the HDS.
Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
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.
Test-drive under these conditions:
- Engine coolant temperature above 158°F (70°C)
- A/T in D5 position
- Drive at a steady speed between 25 mph (40 km/h) and 55 mph (88 km/h) for 5 minutes, then drive at a steady speed between 15 mph (24 km/h) and 75 mph (120 km/h) for 15 minutes.
NOTE: DTC P0171, P0172, P0174, and/or P0175 may take up to 40 minutes of test driving to set. Using the HDS monitor the AF FB AVE for 15 minutes of driving. If the AF FB AVE stays at about 1.0 (0.0%) there is no problem at this time.
Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
1. YES - If DTC P0171, P0172, P0174, or P0175 is indicated, go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
2. NO - Troubleshooting is complete.