P2B4CB Camshaft Position Actuator Position Sensor B Range/Performance Bank 2
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2B4C stands for an implausible but electrically valid signal from the B sensor watching the exhaust actuator of bank 2. It is the exhaust-side mirror of P2B44, which Mercedes-Benz documents on CAMTRONIC V8s (M176/M177) for intake solenoid 2 of bank 2; for P2B4C itself there is no public manufacturer text. In the same bulletin Mercedes reports the exhaust sensor of solenoid 1 on bank 2 as P34C1 and points to engine software and revised actuator part numbers. CARB names a lift-mechanism pin that never arrives where it should as a failure the OBD system must find, which is what this feedback check exists for. Sticking pins and deposits are therefore the main suspects. Bank 1 counterpart: P2B48.
- What you may notice
- Check engine light on
- Lift system or cylinder deactivation in limp-home
- Higher part-load consumption
- Likely causes
- LikelyExhaust actuator pin sticking (deposits, wear)
- PossibleEngine control software outdated
- RareIntermittent contact in the sensor signal
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.