P2C28
Fuel Injector Group B Supply Sense Circuit High
Voltage on the supply sense circuit of fuel injector group B is above the expected window. Indicates overvoltage or wire shorted to B+.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Misfire or rough idle on the affected cylinder
- Increased fuel consumption
- Possible fuel smell or smoke from exhaust
Common causes
Ordered by how often each turns out to be the cause.
- Alternator regulator drift - overvoltageCommon
- Sense wire shorted to B+Possible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Fuel Injector Group B
- Wiring Harness
- ECM
P2C28 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.