P234B
Cylinder 9 Pressure Sensor Circuit High
Cylinder 9 pressure sensor above upper plausibility — open signal or short to B+. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Signal line shorted to supplyCommon
- Sensor ground openPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Cylinder Pressure Sensor 9
P234B is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.