Powertrain, generic (extended)

P2B4D B Camshaft Position Actuator Position Sensor B Circuit Low Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

A too-low signal from position sensor B at the bank 2 exhaust camshaft actuator sets P2B4D. In practice this is a signal wire touching ground, a shorted sensor, or a sensor that gets no supply. The closest documented case is P34C2 on Mercedes M176/M177 V8s, where solenoid 1 on the bank 2 exhaust side reports a sensor short to ground; P2B4D is not described by any manufacturer in public. That bulletin also points at heat-damaged wiring near the windshield, so inspect the harness on the bank 2 side behind the engine. Repairs range from a wire splice to a new actuator with integrated sensor. CARB requires low-signal faults of such sensors to be recognised. Exhaust high fault on bank 2: P2B4E.

Likely causes

Signal wire touching ground (heat or chafe damage)
Sensor in the actuator shorted
No supply to the sensor

Symptoms

  • Check engine light on
  • Exhaust lift change on bank 2 out of action
  • Possibly limp-home message of the lift system

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–650
Time0.5–3.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

b camshaft position actuator pos sensor b b2wiring harnessecm

Related codes

P2B45P2B49P2B4BP2B4CP2B4EP34C2

References: law.cornell.edu, ntn-snr.com, static.nhtsa.gov.