OBD-II code · Powertrain (generic, extended)
P28BF Cylinder 12 Ion Current Sense Circuit High
Ion current from cylinder 12 is above the expected window. Cross-coupled signal, biased reference, or sensor fault.
Is it safe to drive with P28BF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyInductive cross-coupling from ignition coil primary
- PossibleSense reference voltage biased
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- Parts involved
- Spark Plug Cyl 12, Ignition Coil Cyl 12, Ion Sense Module
Related codes
- P2893Cylinder 1 Ion Current Sense Circuit High
- P2897Cylinder 2 Ion Current Sense Circuit High
- P289BCylinder 3 Ion Current Sense Circuit High
- P289FCylinder 4 Ion Current Sense Circuit High
- P28A3Cylinder 5 Ion Current Sense Circuit High
- P28A7Cylinder 6 Ion Current Sense Circuit High
- P28ABCylinder 7 Ion Current Sense Circuit High
- P28AFCylinder 8 Ion Current Sense Circuit High
- P28B3Cylinder 9 Ion Current Sense Circuit High
- P28B7Cylinder 10 Ion Current Sense Circuit High
- P28BBCylinder 11 Ion Current Sense Circuit High
- P28BCCylinder 12 Ion Current Sense Circuit
- P28BDCylinder 12 Ion Current Sense Circuit Range/Performance
- P28BECylinder 12 Ion Current Sense Circuit Low
- P28C0Ion Sense Module Supply Voltage Circuit
- P28C1Ion Sense Module Supply Voltage Low
- P28C2Ion Sense Module Supply Voltage High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.