C0420Adaptive Cruise Control Module Internal Performance
- Generic OBD-II code · Chassis
- How the car detects it
- No public document shows a maker using C0420. It does not appear in the openly accessible J2012 lists, in GM's PIP5094 or in the NHTSA bulletin index, so only the module from the title is covered. The ACC module evaluates the radar data and requests engine torque and braking to keep speed and gap, as Bosch outlines. Faults of the module itself are mostly cured by software: Jeep reprograms the ACC module of the 2024 Compass when C0063-9A, a yaw rate operating-condition code, is set with the check engine lamp, naming ACC software as the cause; Land Rover corrected a wrong ACC module calibration on 2019 Range Rover Sport mild hybrids in service action N343NAS1. An internal performance fault normally disables adaptive cruise and related assists until the module passes its self-test.
- What you may notice
- Adaptive cruise control and related assists unavailable
- Driver assist warning in the instrument cluster
- Likely causes
- LikelyACC module software or calibration out of date
- PossibleLow or unstable supply voltage during self-test
- RareInternal hardware fault of the ACC module
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.