C0420
Adaptive Cruise Control Module Internal Performance
The adaptive cruise control module has reported an internal performance fault — for example self-test failure, supply voltage out of range or invalid configuration. ACC is disabled.
The adaptive cruise control module has reported an internal performance fault — for example self-test failure, supply voltage out of range or invalid configuration. ACC is disabled.
Common causes
- high
ACC module internal fault
One of the most commonly reported causes for this code — check this first.
Typical part cost: $330-1980
- medium
Supply voltage out of range
A plausible cause — test and verify before replacing parts.
Typical part cost: $330-1980
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First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
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Related codes
See related trouble codes
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Frequently asked questions
What does C0420 mean?
C0420 means "Adaptive Cruise Control Module Internal Performance". It is a generic OBD-II code that points to a fault in the chassis.
What are the most common causes of C0420?
acc module internal fault; supply voltage out of range; module configuration invalid after part exchange — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
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