OBD-II code · Powertrain (generic, extended)
P234F Cylinder 9 Pressure Variation Low
Cylinder-to-cylinder pressure variation on cylinder 9 is below the calibrated minimum — pressure stays unusually constant cycle-to-cycle, often a sign that the closed-loop combustion controller has lost authority or the sensor signal is filtered.
Is it safe to drive with P234F?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyWeak combustion - low cycle-to-cycle variation
- PossiblePressure sensor signal amplitude low
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1.5–6 h
- Emissions test
- Likely to fail
- Parts involved
- Cylinder 9 Combustion, Cylinder Pressure Sensor 9
Related codes
- P039CCylinder 1 Pressure Variation Low
- P03A6Cylinder 2 Pressure Variation Low
- P03B0Cylinder 3 Pressure Variation Low
- P03BACylinder 4 Pressure Variation Low
- P03C4Cylinder 5 Pressure Variation Low
- P03CECylinder 6 Pressure Variation Low
- P03D8Cylinder 7 Pressure Variation Low
- P03E2Cylinder 8 Pressure Variation Low
- P236DCylinder 12 Pressure Variation Low
- P234CCylinder 9 Pressure Sensor Circuit Intermittent or Erratic
- P234DCylinder 9 Pressure Too Low
- P234ECylinder 9 Pressure Too High
- P2350Cylinder 9 Pressure Variation High
- P2351Cylinder 9 Combustion Performance
- P2352Cylinder 10 Pressure Sensor Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.