C056D
2 owner reports and 262 manufacturer filings across 74 model years from Buick, Cadillac, Chevrolet, GMC.
Where C056D shows up
Source: NHTSA manufacturer communications and complaintsShowing the 25 model years where C056D appears most; it is on file for 74 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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C056D by make
The same record, one make at a time: the model years, bulletins and owner reports that name C056D on that maker’s vehicles.
What it gets filed under
262 manufacturer filings name C056D. 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 C056D.
- PIT5662G Service bulletin2022-11-18 · Equipment — Other — Owners/Service/Other Manual
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
- 22-NA-107 Service bulletin2022-07-21 · Power Train
- This service bulletin provides repair information to correct a customer concern of a Service AWD Message in DIC at Ignition On with DTC C056D Set.
- 22-NA-107 Service bulletin2022-05-20 · Power Train — Automatic Transmission
- This service bulletin provides repair information to correct a customer concern of a Service AWD Message in DIC at Ignition On with DTC C056D Set.
- PIT5662G Service bulletin2022-03-25 · Parking Brake
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
- PIT5662F Service bulletin2021-08-19 · Parking Brake
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
- PIT5662D Service bulletin2020-01-09 · Parking Brake
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
What C056D means
Source: SAE J2012 / OBD-IIC056D 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 C056D
Source: NHTSA files and the OBD-II standardCan I keep driving with C056D 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.