P28C1
Ion Sense Module Supply Voltage Low
Supply voltage on the ion sense module is below the expected window. Wiring shorted to ground, blown fuse, or upstream regulator fault.
Supply voltage on the ion sense module is below the expected window. Wiring shorted to ground, blown fuse, or upstream regulator fault.
Common causes
- high
Module supply fuse blown
One of the most commonly reported causes for this code — check this first.
Typical part cost: $110-660
- medium
Supply wire shorted to ground
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 P28C1 mean?
P28C1 means "Ion Sense Module Supply Voltage Low". It is a generic OBD-II code that points to a fault in the auxiliary emission controls.
What are the most common causes of P28C1?
module supply fuse blown; supply wire shorted to ground — 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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