OBD-II code · Powertrain (generic, extended)
P2891 Cylinder 1 Ion Current Sense Circuit Range/Performance
The ion current signal from cylinder 1 is outside the expected range for combustion conditions. Combustion quality cannot be assessed reliably.
Is it safe to drive with P2891?
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 1, Ignition Coil Cyl 1, Ion Sense Module
Related codes
- 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
- P28BDCylinder 12 Ion Current Sense Circuit Range/Performance
- P288EShift Fork "A" Actuator Control Circuit Driver Current/Temperature Too High
- P288FShift Fork "B" Actuator Control Circuit Driver Current/Temperature Too High
- P2890Cylinder 1 Ion Current Sense Circuit
- P2892Cylinder 1 Ion Current Sense Circuit Low
- P2893Cylinder 1 Ion Current Sense Circuit High
- P2894Cylinder 2 Ion Current Sense Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.