P289BCylinder 3 Ion Current Sense Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P289B signals that the ion channel of cylinder 3 sits permanently above its upper limit. A conductor touching battery voltage, a coil that couples ignition energy into its measuring output, or a lost ground reference are the usual electrical reasons. Saab shows a comparable bank-level check on the Trionic T7 V6, where cylinder 3 belongs to bank 1 together with 1 and 5: its code P1313 is set when the combustion detection line stays above 5 V for 200 combustions and clears after 300 without fault. On the 2009 four-cylinder module, cylinder 3 has trigger input pin 2 and ion input pin 8, which makes targeted voltage checks easy. No manufacturer publishes P289B. The low-side counterpart is P289A.
- What you may notice
- MIL with high ion signal fault on cylinder 3
- Knock on cylinder 3 may go undetected, so timing is retarded
- Reduced pulling power
- Likely causes
- LikelyIon signal wire of cylinder 3 shorted to battery or supply voltage
- PossibleCoil 3 coupling ignition energy into its measuring output
- RareMissing ground reference at coil 3 or the processing 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: €40 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.