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2001 Ford F150 5.4L Engine P1131, P1151, P0171, P0174 O2 Sensor Codes - Diagnosis & Aftermarket Cold Air System Impact

Model: 2001 F150 Fault Code: P0000 Posted: 2019-09-04 18:14

Hello, I have a 2001 Ford F15-than with a 5.4L V8 engine. I recently checked the onboard diagnostics and found four trouble codes: P1131, P1151, P0171, and P0174. The truck runs smoothly and starts easily, so I'm wondering if this is simply an oxygen sensor issue or if there's a more complex underlying problem. I also have an aftermarket cold air intake system installed. Could that be contributing to the misreads? Any insights or troubleshooting steps would be greatly appreciated. Thanks in advance for your help.

Related fault codes
P0000P0001P0002P0003
Comments (3)
Anonymous 2019-09-04 18:41

Can you share the freeze frame data associated with these error codes? This helps determine whether the issue occurs at idle, higher RPMs, or under specific driving conditions.

Anonymous 2019-09-04 19:36

I just used my palm-based OBD-II code reader while the engine was running and received the same four codes: P1131, P1151, P0171, and P0174. I'm not sure how to retrieve freeze frame data—can anyone guide me on that?

Anonymous 2019-09-04 22:17

Can you check your fuel trims at idle and compare them with those at 2500 RPMs? If the fuel trim becomes less positive at higher RPM, it may indicate a vacuum leak. If the trim becomes more positive at higher RPM, this could point to an MAF sensor issue or fuel delivery problems. A P0171 code typically indicates one or more of the following: - The Mass Air Flow (MAF) sensor is dirty or faulty (note: over-oiled air filters can cause MAF contamination). - The MAF sensor may have leaked silicone potting material, especially in older vehicles. - A vacuum leak downstream of the MAF sensor. - Possible cracks in vacuum hoses or PCV lines/connections. - A stuck-open or faulty PCV valve. - A failed or stuck oxygen sensor (Bank 1, Sensor 1). - Sticking, plugged, or malfunctioning fuel injectors. - Low fuel pressure—possibly due to a clogged or dirty fuel filter. - An exhaust leak between the engine and the first oxygen sensor. For more details: https://www.example.com/p0171