What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer communications
9Original wording in English
MAZDA
Reported code forms C0021:52
When switching to the maintenance mode, U3000:53 and the related DTCs are stored, but the DTCs will not be cleared automatically after finishing the maintenance mode. It is necessary to clear the DTCs completely after…
CADILLAC, CHEVROLET, GMC
Reported code forms C0021
This technical bulletin provides repair information to correct a customer concern of Loss of Brake Assist, Various Messages Displayed in Driver Information Center (DIC), Brake Pedal Travel and Apply May Feel Different,…
CHEVROLET, GMC
Reported code forms C0021
This Preliminary information communicates repair information on Service Brake System, Reduced Engine Power, and Speed Limited messages on the DIC. Along with these messages, a SES MIL will be on and the brake pedal may…
CHEVROLET, GMC
Reported code forms C0021
This Preliminary information communicates an issue with DTC P0606 and C0021 setting after completing campaign N192268090 and advises to reprogram the BSCM with updated calibrations available in Tis2Web.
CHEVROLET, GMC
Reported code forms C0021
This Preliminary information communicates an issue with DTC P0606 and C0021 setting after completing campaign N192268090 and advises to reprogram the BSCM with updated calibrations available in Tis2Web.
CHEVROLET, GMC
Reported code forms C0021
This Preliminary information communicates an issue with DTC P0606 and C0021 setting after completing campaign N192268090 and advises to reprogram the BSCM with updated calibrations available in Tis2Web.
Check vehicle applicability
17A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Cadillac | CT6 | 2020 |
| Cadillac | CT6 | 2019 |
| Cadillac | XT5 | 2020 |
| Cadillac | XT5 | 2019 |
| Cadillac | XT6 | 2020 |
| Chevrolet | BLAZER | 2020 |
| Chevrolet | SILVERADO 1500 | 2020 |
| Chevrolet | SILVERADO 1500 | 2019 |
| GMC | ACADIA | 2020 |
| GMC | ACADIA | 2019 |
| GMC | SIERRA 1500 | 2020 |
| GMC | SIERRA 1500 | 2019 |
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.