OBD-II code · Powertrain (generic)
P03BB Cylinder 4 Pressure Variation High
Cylinder-to-cylinder pressure variation on cylinder 4 is above the calibrated maximum — combustion is unstable cycle-to-cycle, typical of partial misfire or injector seat erosion.
Is it safe to drive with P03BB?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyPartial misfire
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–6 h
- Emissions test
- Likely to fail
- Parts involved
- Cylinder Pressure Sensor
Related codes
- P039DCylinder 1 Pressure Variation High
- P03A7Cylinder 2 Pressure Variation High
- P03B1Cylinder 3 Pressure Variation High
- P03B3Cylinder 4 Pressure Sensor Circuit
- P03C5Cylinder 5 Pressure Variation High
- P03CFCylinder 6 Pressure Variation High
- P03D9Cylinder 7 Pressure Variation High
- P03E3Cylinder 8 Pressure Variation High
- P2350Cylinder 9 Pressure Variation High
- P235ACylinder 10 Pressure Variation High
- P2364Cylinder 11 Pressure Variation High
- P236ECylinder 12 Pressure Variation High
- P03B8Cylinder 4 Pressure Too Low
- P03B9Cylinder 4 Pressure Too High
- P03BACylinder 4 Pressure Variation Low
- P03BCCylinder 4 Combustion Performance
- P03BDCylinder 5 Pressure Sensor Circuit
- P03BECylinder 5 Pressure Sensor Circuit Range/Performance
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.