P0171 The engine is running lean on bank 1: too much air, or not enough fuel, for the mixture the computer wants
39 owner reports and 788 manufacturer filings across 308 model years from Acura, Buick, Cadillac, Chevrolet and others.
Where P0171 shows up
Source: NHTSA manufacturer communications and complaintsShowing the 25 model years where P0171 appears most; it is on file for 308 in total.
A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.
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P0171 by make
The same record, one make at a time: the model years, bulletins and owner reports that name P0171 on that maker’s vehicles.
What it gets filed under
What owners said
Source: NHTSA complaint databaseOwners’ own words, one per nameplate, scrubbed of anything identifying. These are unverified reports filed with NHTSA — they are what was said, not a finding that it was true.
On September 18,2026 owner #3 bought the vehicle on December 9,2026 at the time of purchase it had 46,545 on September 17 check engine light came on and the diagnostic code came up as P0171 lean bank one from Pep Boys
A diagnostic scan performed afterward showed DTC P0171 (System Too Lean), but the code was subsequently cleared
These are a few of the codes it reads, although some codes come and go, but these remain on: P12E7, P12EC, P12F4, P12F9, P0121, P0171, P0161, P0131, P069E, B097B, B1395, B1516, B1517, B260E, B260E, B2615, B2745, U0800, U1808, U0109, U007C
My vehicle had a check engine light code of P0171 and the odor of burning oil
The vehicle was then taken to an AutoZone, where a handheld diagnostic machine retrieved diagnostic trouble codes: P0017 (crankshaft) and P0171 (system too lean), and it was observed that the oil reservoir was empty
788 manufacturer filings name P0171. Start with what the maker wrote down.
A code names the test that failed, not the part. A bulletin that names it is often a diagnosis someone has already written down — quote its number at the service desk.
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names P0171.
- 09-005-26 Service bulletin2026-03-12 · Fuel/Propulsion System
- Not applicable to vehicles built for US market. Methanol In Fuel - Diagnostic Trouble Code (DTC) P0171 Customers may experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may SYMPTOM: exhibit/set the following Diagnostic Trouble Code (DTC): ● P0171-00 - System Too Lean (Bank 1). Customers can also experience one or more of the following: ● Engine misfire. ● Rough engine idle.
- 08-088-25 REV. B Service bulletin2025-06-25 · Electrical System
- Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician must find one or more of the following Diagnostic Trouble Codes (DTCs) have been set: ● U0168 - Lost Communication With Vehicle Security Control Module. ● P0629 - Fuel Pump Control Circuit High. ● P0171 - Fuel system Lean. ● P0087 - Fue
- 18-025-25 Service bulletin2025-05-18 · Power Train
- "Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0629 - Fuel Pump Control Circuit High. ● P0171 - Fuel system Lean. ● P0087 - Fuel Rail Pressure Too Low – Bank 1. ● P16F0-00 - SPI Comm Hardware Fault. Customers may also experienc
- 08-088-25 REV. A Service bulletin2025-04-30 · Unknown Or Other
- "Flash: Powertrain Control Module (PCM) Updates. Customers must experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician must find one or more of the following Diagnostic Trouble Codes (DTCs) have been set: ● **U0168 - Lost Communication With Vehicle Security Control Module.** ● P0629 - Fuel Pump Control Circuit High. ● P0171 - Fuel system Lean. ● P0087
- 08-088-25 Service bulletin2025-03-28 · Power Train
- "Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician must find one or more of the following Diagnostic Trouble Codes (DTC)s have been set: ● P0629 - Fuel Pump Control Circuit High. ● P0171 - Fuel system Lean. ● P0087 - Fuel Rail Pressure Too Low - Bank 1. Customers may also experience on
- 18-070-24 Service bulletin2024-09-14 · Unknown Or Other
- "Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician must find one or more of the following Diagnostic Trouble Codes (DTC)s have been set: ● P0629 - Fuel Pump Control Circuit High. ● P0171 - Fuel system Lean. ● P0087 - Fuel Rail Pressure Too Low - Bank 1. Customers may also experience th
What P0171 means
Source: SAE J2012 / OBD-IIThe engine is running lean on bank 1: too much air, or not enough fuel, for the mixture the computer wants.
A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.
Common questions about P0171
Source: NHTSA files and the OBD-II standardCan I keep driving with P0171 stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light means a fault was logged and the car should be checked soon; a flashing light means a severe misfire — slow down and get it seen as soon as possible, because severe misfire can quickly damage the catalytic converter. The safe read of this page is the mileage and the components, not permission.
Does a code mean the car is recalled?
No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.
Why do the counts here differ from other sites?
Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.
Will clearing the code fix it?
Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.