P2892Cylinder 1 Ion Current Sense Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2892 says the ion measurement of cylinder 1 delivers a signal that stays below the expected range. Electrically this points to a signal line shorted to ground or a measuring stage that no longer builds up its bias voltage; Saab, for example, applies around 120 V across the plug gap between sparks to obtain the current. A heavily fouled plug can also drag the level down by bleeding off the measuring voltage. When the reading is stuck low, the module can no longer judge combustion in cylinder 1 and typically falls back to a safe ignition map. No manufacturer has published this code; on Saab Trionic T8 engines the cylinder 1 ion line runs from coil pin 4 to the processing module. The high-side fault is P2893, the cylinder 2 equivalent P2896.
- What you may notice
- MIL and stored fault for cylinder 1
- Noticeably less power from retarded ignition
- Possibly unreported misfires on cylinder 1
- Likely causes
- LikelyIon signal wire of cylinder 1 shorted to ground
- PossibleCoil 1 no longer generates its measuring voltage
- PossibleSpark plug of cylinder 1 with leakage path through deposits
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.