P28C2
Ion Sense Module Supply Voltage High
Supply voltage on the ion sense module is above the expected window. Charging system overvoltage or upstream regulator fault.
Supply voltage on the ion sense module is above the expected window. Charging system overvoltage or upstream regulator fault.
Common causes
- high
Alternator regulator drift - overvoltage
One of the most commonly reported causes for this code — check this first.
Typical part cost: $110-660
- medium
Supply wire shorted to B+
A plausible cause — test and verify before replacing parts.
Typical part cost: $110-660
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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 P28C2 mean?
P28C2 means "Ion Sense Module Supply Voltage High". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P28C2?
alternator regulator drift - overvoltage; supply wire shorted to b+ — 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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