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 60 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.
What it gets filed under
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names C056D. Quoting the document number at a service desk is often the fastest route to a diagnosis someone has already written down.
- PIT5662G2022-11-18 · Equipment — Other — Owners/Service/Other Manual
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
- 22-NA-1072022-07-21 · 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-1072022-05-20 · Electrical System
- 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.
- PIT5662G2022-03-25 · Parking Brake
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
- PIT5662F2021-08-19 · Parking Brake
- This Preliminary information communicates information to diagnose DTC C056D or C056E.
- PIT5662D2020-01-09 · 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 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.