Either this guy is not an honest mechanic and trying to pull a fast one over you or he knows nothing about the system or problem.
DTC P0171: FUEL SYSTEM TOO LEAN; DTC 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.
†P0101, P0102, P0103: Mass air flow (MAF) sensor (2003-2004 SULEV, LX-P models and 2005-2007 models)
†P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor
†P0133, P1172 (2005-2007 models), P1157, P2195, P2238,
†P2252, P2A00: Air fuel ratio (A/F) sensor (Sensor 1)
†P0134, P0135: Air fuel ratio (A/F) sensor (Sensor 1) heater
†P0137, P0138, P0139, P2270 (2005-2007 models), P2271 (2005-2007 models): Secondary HO2S (Sensor 2)
†P0141: Secondary HO2S (Sensor 2) heater
†P2646, P2647, P2648, P2649: VTEC system
†P0401, P0404, P0406, P2413: Exhaust gas recirculation (EGR) system
†P2279: Intake air leakage (2003-2004 except SULEV, LX-P models)
†P0443, P0496: EVAP canister purge valve (2003-2004 SULEV, LX-P models and 2005-2007 models)
†Check the fuel pressure.
Is the fuel pressure OK?
YES
†2003-2004 SULEV, LX-P models and 2005-2007 models: Go to step 2.
†2003-2004 except SULEV, LX-P models: Check the engine valve clearances and adjust if necessary. If the valve clearances are OK, replace the injectors, then go to step 7.
NO
†If the pressure is too high, replace the fuel pressure regulator
then go to step 7.
†If the pressure is too low, check the fuel pump and the fuel feed line. Then go to step 7.
2. Check these parts for vacuum leaks:
†PCV valve
†PCV hose
†EVAP canister purge valve
†Throttle body
†Intake manifold
†Brake booster hose
Are the parts OK?
YES - Go to step 3.
NO - Repair or replace parts with leaks, then go to step 7.
3. 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.
4. Check for these conditions:
†ECT SENSOR above 176°F (80°C)
†M/T in neutral (A/T in Park or neutral)
†All electric load off
5. Monitor the ENG SPD in the DATA LIST with the HDS, and hold the engine speed at 4,500 rpm. Once the engine speed is met, hold the accelerator pedal steady for more than 10 seconds.
Did the engine speed vary more than 100 rpm from 4,500 rpm?
YES - Repeat step 5.
NO - Go to step 6.
6. While holding the engine speed at 4,500 rpm, check the MAF SENSOR in the DATA LIST with the HDS.
Is there about 14-20 gm/s?
YES - Check the engine valve clearances and adjust if necessary. If the valve clearances are OK, replace the injectors then go to step 7.
NO - Replace the MAF sensor/IAT sensor, then go to step 7.
7. Turn the ignition switch ON (II).
8. Reset the ECM/PCM with the HDS.
9. Do the ECM/PCM idle learn procedure.
10. 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.
11. Test-drive under these conditions:
†Engine coolant temperature above 176°F (80°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.
12. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0171 or P0175 indicated?
YES - Go to step 1.
NO - Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
P0224 = Throttle/Pedal Position Sensor/Switch "B" Circuit Intermittent.
Check the throttle position sensor wireconnector. It could be loose or dislodged causing the problem. If P0224 is rectified, P0171 might go away as well.
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Wednesday, December 15th, 2010 AT 2:37 PM