Chassis Codes (C Codes)
Chassis codes cover the systems that control the car beyond the engine: anti-lock brakes (ABS), traction and stability control, electronic steering, air suspension, and tire-related monitoring. They usually turn on the ABS or stability-control warning lamp rather than the check engine light, and a basic engine-only scan tool may not read them — you need a scanner that covers ABS and chassis systems.
Many chassis codes trace back to wheel speed sensors and their wiring, because those signals feed the brakes, stability control, and often the speedometer and transmission shift logic as well.
There are 498 generic C codes in the database. Browse the complete list on the codes list page.
System clusters
Chassis — Brakes, Steering and Suspension
498 codes