OBD-II code · Powertrain (generic, extended)
P28B8 Cylinder 11 Ion Current Sense Circuit
The ECM cannot read a valid ion current signal from cylinder 11. Ion current sensing relies on the spark plug acting as an electrode after combustion.
Is it safe to drive with P28B8?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIon sense module failed
- PossibleWiring or connector fault
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 11, Ignition Coil Cyl 11, Ion Sense Module
Related codes
- P2890Cylinder 1 Ion Current Sense Circuit
- P2894Cylinder 2 Ion Current Sense Circuit
- P2898Cylinder 3 Ion Current Sense Circuit
- P289CCylinder 4 Ion Current Sense Circuit
- P28A0Cylinder 5 Ion Current Sense Circuit
- P28A4Cylinder 6 Ion Current Sense Circuit
- P28A8Cylinder 7 Ion Current Sense Circuit
- P28ACCylinder 8 Ion Current Sense Circuit
- P28B0Cylinder 9 Ion Current Sense Circuit
- P28B4Cylinder 10 Ion Current Sense Circuit
- P28BCCylinder 12 Ion Current Sense Circuit
- P28B5Cylinder 10 Ion Current Sense Circuit Range/Performance
- P28B6Cylinder 10 Ion Current Sense Circuit Low
- P28B7Cylinder 10 Ion Current Sense Circuit High
- P28B9Cylinder 11 Ion Current Sense Circuit Range/Performance
- P28BACylinder 11 Ion Current Sense Circuit Low
- P28BBCylinder 11 Ion Current Sense Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.