OBD-II code · Powertrain (generic, extended)
P28B2 Cylinder 9 Ion Current Sense Circuit Low
Ion current from cylinder 9 is below the expected window. Spark plug fouled, signal wire shorted to ground, or sensing path interrupted.
Is it safe to drive with P28B2?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySpark plug fouled with carbon or oil
- PossibleSense wire shorted to ground
- 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 9, Ignition Coil Cyl 9, Ion Sense Module
Related codes
- P2892Cylinder 1 Ion Current Sense Circuit Low
- P2896Cylinder 2 Ion Current Sense Circuit Low
- P289ACylinder 3 Ion Current Sense Circuit Low
- P289ECylinder 4 Ion Current Sense Circuit Low
- P28A2Cylinder 5 Ion Current Sense Circuit Low
- P28A6Cylinder 6 Ion Current Sense Circuit Low
- P28AACylinder 7 Ion Current Sense Circuit Low
- P28AECylinder 8 Ion Current Sense Circuit Low
- P28B6Cylinder 10 Ion Current Sense Circuit Low
- P28BACylinder 11 Ion Current Sense Circuit Low
- P28BECylinder 12 Ion Current Sense Circuit Low
- P28AFCylinder 8 Ion Current Sense Circuit High
- P28B0Cylinder 9 Ion Current Sense Circuit
- P28B1Cylinder 9 Ion Current Sense Circuit Range/Performance
- P28B3Cylinder 9 Ion Current Sense Circuit High
- P28B4Cylinder 10 Ion Current Sense Circuit
- P28B5Cylinder 10 Ion Current Sense Circuit Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.