OBD-II code · Powertrain (generic, extended)
P28BD Cylinder 12 Ion Current Sense Circuit Range/Performance
The ion current signal from cylinder 12 is outside the expected range for combustion conditions. Combustion quality cannot be assessed reliably.
Is it safe to drive with P28BD?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySpark plug aged - electrode shape changed
- PossibleIon sense circuit gain drift
- Less likelySensor element aged beyond calibration window
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
- P2891Cylinder 1 Ion Current Sense Circuit Range/Performance
- P2895Cylinder 2 Ion Current Sense Circuit Range/Performance
- P2899Cylinder 3 Ion Current Sense Circuit Range/Performance
- P289DCylinder 4 Ion Current Sense Circuit Range/Performance
- P28A1Cylinder 5 Ion Current Sense Circuit Range/Performance
- P28A5Cylinder 6 Ion Current Sense Circuit Range/Performance
- P28A9Cylinder 7 Ion Current Sense Circuit Range/Performance
- P28ADCylinder 8 Ion Current Sense Circuit Range/Performance
- P28B1Cylinder 9 Ion Current Sense Circuit Range/Performance
- P28B5Cylinder 10 Ion Current Sense Circuit Range/Performance
- P28B9Cylinder 11 Ion Current Sense Circuit Range/Performance
- P28BACylinder 11 Ion Current Sense Circuit Low
- P28BBCylinder 11 Ion Current Sense Circuit High
- P28BCCylinder 12 Ion Current Sense Circuit
- P28BECylinder 12 Ion Current Sense Circuit Low
- P28BFCylinder 12 Ion Current Sense Circuit High
- P28C0Ion Sense Module Supply Voltage Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.