P12A6
4 owner reports and 547 manufacturer filings across 62 model years from Buick, Cadillac, Chevrolet, GMC.
Where P12A6 shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2020 Chevrolet Silverado | Engine And Engine Cooling | 23 | 1 |
| 2021 GMC Yukon | Engine And Engine Cooling | 22 | — |
| 2021 Cadillac Escalade | Engine And Engine Cooling | 21 | — |
| 2019 Chevrolet Silverado | Engine And Engine Cooling | 20 | — |
| 2020 GMC Terrain | Engine And Engine Cooling | 20 | — |
| 2020 Chevrolet Equinox | Engine And Engine Cooling | 19 | — |
| 2020 Chevrolet Malibu | Engine And Engine Cooling | 19 | — |
| 2020 Chevrolet Silverado 2500HD | Engine And Engine Cooling | 18 | — |
| 2020 GMC Sierra | Engine And Engine Cooling | 18 | — |
| 2020 GMC Sierra 2500HD | Engine And Engine Cooling | 18 | — |
| 2020 Cadillac Escalade | Engine And Engine Cooling | 16 | — |
| 2021 Chevrolet Equinox | Engine And Engine Cooling | 16 | — |
| 2021 Chevrolet Malibu | Engine And Engine Cooling | 16 | — |
| 2020 Chevrolet Suburban | Engine And Engine Cooling | 16 | — |
| 2020 Chevrolet Tahoe | Engine And Engine Cooling | 16 | — |
| 2021 GMC Terrain | Engine And Engine Cooling | 16 | — |
| 2020 GMC Yukon | Engine And Engine Cooling | 16 | — |
| 2019 GMC Sierra | Engine And Engine Cooling | 15 | — |
| 2021 Chevrolet Silverado | Engine And Engine Cooling | 14 | — |
| 2021 Chevrolet Silverado 2500HD | Engine And Engine Cooling | 14 | — |
| 2021 GMC Sierra | Engine And Engine Cooling | 14 | — |
| 2021 GMC Sierra 2500HD | Engine And Engine Cooling | 14 | — |
| 2021 Chevrolet Suburban | Engine And Engine Cooling | 13 | — |
| 2021 Chevrolet Tahoe | Engine And Engine Cooling | 13 | — |
| 2020 Chevrolet Corvette | Engine And Engine Cooling | 12 | — |
| 2020 Chevrolet Silverado 3500HD | Engine And Engine Cooling | 12 | — |
| 2020 GMC Sierra 3500HD | Engine And Engine Cooling | 11 | 1 |
| 2021 Chevrolet Silverado 3500HD | Engine | 7 | — |
| 2021 GMC Sierra 3500HD | Engine | 7 | — |
| 2020 Cadillac CT5 | Engine And Engine Cooling | 6 | — |
| 2021 Buick Encore | Engine And Engine Cooling | 5 | — |
| 2020 Buick Encore | Power Train | 5 | — |
| 2021 Chevrolet Camaro | Engine And Engine Cooling | 4 | 1 |
| 2020 Buick Regal | Engine And Engine Cooling | 4 | — |
| 2019 Buick Regal | Engine And Engine Cooling | 4 | — |
| 2019 Chevrolet Malibu | Engine And Engine Cooling | 4 | — |
| 2021 Chevrolet Trailblazer | Engine And Engine Cooling | 4 | — |
| 2022 GMC Terrain | Air Bags | 4 | — |
| 2022 Chevrolet Silverado 2500HD | Unknown Or Other | 2 | 1 |
| 2019 Chevrolet Silverado 2500HD | Engine And Engine Cooling | 3 | — |
| 2017 Chevrolet Silverado 2500HD | Engine And Engine Cooling | 3 | — |
| 2021 GMC Acadia | Power Train | 3 | — |
| 2019 GMC Sierra 2500HD | Engine And Engine Cooling | 3 | — |
| 2018 GMC Sierra 2500HD | Engine And Engine Cooling | 3 | — |
| 2017 GMC Sierra 2500HD | Engine And Engine Cooling | 3 | — |
| 2023 Chevrolet Equinox | Exterior Lighting | 2 | — |
| 2022 Chevrolet Equinox | Electrical System | 2 | — |
| 2023 Chevrolet Silverado 2500HD | Unknown Or Other | 2 | — |
| 2023 Chevrolet Silverado 3500HD | Unknown Or Other | 2 | — |
| 2022 Chevrolet Silverado 3500HD | Unknown Or Other | 2 | — |
| 2019 Chevrolet Silverado 3500HD | Engine And Engine Cooling | 2 | — |
| 2018 Chevrolet Silverado 3500HD | Engine And Engine Cooling | 2 | — |
| 2017 Chevrolet Silverado 3500HD | Engine And Engine Cooling | 2 | — |
| 2023 GMC Sierra 2500HD | Unknown Or Other | 2 | — |
| 2022 GMC Sierra 2500HD | Unknown Or Other | 2 | — |
| 2023 GMC Sierra 3500HD | Unknown Or Other | 2 | — |
| 2022 GMC Sierra 3500HD | Unknown Or Other | 2 | — |
| 2019 GMC Sierra 3500HD | Engine And Engine Cooling | 2 | — |
| 2017 GMC Sierra 3500HD | Engine And Engine Cooling | 2 | — |
| 2021 Chevrolet Express | Engine And Engine Cooling | 1 | — |
Showing the 60 model years where P12A6 appears most; it is on file for 62 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.
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.
Check 4x4, check DEF( def is still at half full), check trailer( no trailer is connected) Took to dealership, 4 active codes P0336, P12A6, U029D, U029E
The engine light has come on 3 times with a truck with only 9000 miles on it I took it to the dealership who gave me a code of P12A6 they told me Chevrolet is aware of this problem but has not come up with solution yet or even wrote a…
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names P12A6. Quoting the document number at a service desk is often the fastest route to a diagnosis someone has already written down.
- PIT6396A2025-08-05 · Unknown Or Other
- This PI communicates an issue with a SES MIL with DTC P2535, P12A6, P10DA and/or C111B maybe set after replacing the fuel pump driver module. Engineering is working on a fix, but in the meantime, dealers are to install a diode.
- PIT63962025-06-11 · Unknown Or Other
- This PI communicates an issue with a SES MIL with DTC P2535, P12A6, P10DA and/or C111B maybe set after replacing the fuel pump driver module. Engineering is working on a fix, but in the meantime, dealers are to install a diode.
- 22-NA-1702023-09-12 · Air Bags
- This bulletin offers Information on Possible Crank No Start or Extended Crank with DTC P12A6 or Service Safety Restraints message on DIC, with B0073.
- 22-NA-1702022-09-07 · Exterior Lighting
- This bulletin offers Information on Possible Crank No Start or Extended Crank with DTC P12A6 or Service Safety Restraints message on DIC, with B0073.
- 20-NA-2182022-05-19 · Engine And Engine Cooling
- This service bulletin provides repair information to correct a customer concern of Possible Crank No Start or Extended Crank with DTC P12A6.
- 20NA2182021-05-07 · Electrical System
- This service bulletin provides repair information to correct a customer concern of Possible Crank No Start or Extended Crank with DTC P12A6.
What P12A6 means
Source: SAE J2012 / OBD-IIP12A6 is a manufacturer-specific code: the second character is a 1, which under the OBD-II standard hands the definition to whoever built the vehicle. The same code can mean one thing on a Ford and something unrelated on a Hyundai. Any site that prints a single definition for it is guessing.
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 P12A6
Source: NHTSA files and the OBD-II standardWhy does this page not define P12A6?
Because it cannot be defined honestly. The second character of a trouble code says who owns its meaning, and a 1 or a 3 hands that to the manufacturer. Sites that print one definition for a manufacturer-specific code are showing you one automaker's meaning and hoping it is yours.
Can I keep driving with P12A6 stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light generally means the fault was logged and the vehicle is in a reduced-risk mode; a flashing light means stop soon, because a misfiring engine can destroy a catalytic converter in minutes. 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.