P2898Cylinder 3 Ion Current Sense Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2898 marks a basic circuit failure in the ion current measurement of cylinder 3: the engine computer receives nothing it can evaluate from that spark plug. With ion sensing, the plug doubles as a probe, because a bias voltage across the gap drives a small current through the burning, conductive gas. On Saab's Trionic four-cylinders, cylinder 3 shares its start-up spark with cylinder 2 until synchronisation is reached, and only the combustion signal reveals which of the two really burned. The T7 version groups cylinders 3 and 4 on one detector, whose open line to the engine module Saab reports with its own code P1334. No manufacturer publicly documents P2898 itself; coil 3, its connector and the plug are the first checks.
- What you may notice
- MIL with ion fault stored for cylinder 3
- Starting may take longer while cylinder identification is uncertain
- Engine runs with cautious ignition timing and somewhat less power
- Likely causes
- LikelyIgnition coil of cylinder 3 whose ion measuring stage has failed
- PossibleLoose or corroded connector at coil 3 or broken ion signal wire
- RareFaulty cylinder 3 input in the ion processing module or engine module
- 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: €60 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.