P2B55B Camshaft Profile Actuator B Control Stuck On Bank 1
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2B55 flags actuator B on the bank 1 exhaust camshaft as stuck on. Even GM, whose L3B four has a second exhaust actuator and uses P2B51 for it, lists no stuck-on code for that actuator in its 2019 and 2025 tables; no other maker documents P2B55 publicly either. The fault logic can be inferred from the intake twin P2B53: a pin that does not report back to its rest position after shifting. NTN-SNR lists the code as component permanently active, and CARB (e)(13) covers it as a valve control fault. A sleeve held in one exhaust profile changes scavenging and turbo response, and the engine control normally locks out further switching. Related: P2B51 (stuck off), P2B39–P2B3B (circuit).
- What you may notice
- Check engine light on
- Changed turbo response or reduced power
- Possible metallic noise from the camshaft area
- Likely causes
- LikelyPin of exhaust actuator B does not retract, often from heat and deposits
- PossibleSolenoid stays powered because of a wiring or driver fault
- RareDamaged shift groove holds the pin
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.