OBD-II code · Powertrain (generic, extended)
P28A3 Cylinder 5 Ion Current Sense Circuit High
Ion current from cylinder 5 is above the expected window. Cross-coupled signal, biased reference, or sensor fault.
Is it safe to drive with P28A3?
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 5, Ignition Coil Cyl 5, 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
- 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
- P28BFCylinder 12 Ion Current Sense Circuit High
- P28A0Cylinder 5 Ion Current Sense Circuit
- P28A1Cylinder 5 Ion Current Sense Circuit Range/Performance
- P28A2Cylinder 5 Ion Current Sense Circuit Low
- P28A4Cylinder 6 Ion Current Sense Circuit
- P28A5Cylinder 6 Ion Current Sense Circuit Range/Performance
- P28A6Cylinder 6 Ion Current Sense Circuit Low
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.