P0494
1 owner report and 23 manufacturer filings across 13 model years from Buick, Cadillac, Chevrolet, GMC.
Where P0494 shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports | Parts |
|---|---|---|---|---|
| 2021 Buick Enclave | Engine | 2 | — | |
| 2026 Buick Envision | Not specified | 2 | — | |
| 2021 Cadillac XT5 | Engine | 2 | — | |
| 2020 Cadillac XT5 | Engine | 2 | — | |
| 2021 Cadillac XT6 | Engine | 2 | — | |
| 2021 Chevrolet Blazer | Engine | 2 | — | |
| 2020 Chevrolet Blazer | Engine | 2 | — | |
| 2021 Chevrolet Traverse | Engine | 2 | — | |
| 2021 GMC Acadia | Engine | 2 | — | |
| 2020 GMC Acadia | Engine | 2 | — | |
| 2023 GMC Hummer EV | Equipment | 2 | — | |
| 2021 Buick Envision | Air Bags | 1 | — | |
| 2022 GMC Canyon | Electrical System | — | 1 | Battery → |
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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What it gets filed under
23 manufacturer filings name P0494. 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 P0494.
- PIP6126 Service bulletin2026-09-26 · Unknown Or Other
- This Preliminary information communicates the potential for dtc p0494 to be stored in the ECM due to potential software anomaly
- PIT6546 Service bulletin2026-09-02 · Unknown Or Other
- This Preliminary information describes a condition where engineering is working on a solution to a P0494 DTC stored in the ECM.
- PIT5925B Service bulletin2023-04-24 · Engine And Engine Cooling — Cooling System
- This Preliminary information communicates to the field that water hitting the cooling fans can set a false DTC: P0494 for the 2022-2024 HUMMER EV.
- PIT5925A Service bulletin2023-03-23 · Equipment — Electrical
- This Preliminary information communicates to the field that water hitting the cooling fans can set a false DTC: P0494 for the 2022-2023 HUMMER EV.
- PIE0657A Service bulletin2022-01-14 · Air Bags
- This engineering information (EI) closure ends the need for further information from technicians in regards to the Check Engine Lamp illuminated on the Driver Information Center (DIC) with P0494 Set.
- 21NA088 Service bulletin2021-05-03 · Engine
- This service bulletin provides repair information to correct a customer concern of a Check Engine Light Displayed on Driver Information Center (DIC), Engine Cooling Fan Windmilling, DTC P0494 Set.
What P0494 means
Source: SAE J2012 / OBD-IIP0494 sits in the generic range of the OBD-II standard, so it means the same thing on every vehicle sold in the United States — but WhichTrim does not carry a definition for it and will not invent one. What is on this page is the record: who named it and on what.
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 P0494
Source: NHTSA files and the OBD-II standardCan I keep driving with P0494 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.