Powertrain, generic (extended)

P2B46 A Camshaft Position Actuator Position Sensor B Circuit High Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2B46 flags a signal from position sensor B on the bank 2 intake camshaft actuator that is stuck too high. Most often the sensor has lost its ground, the signal line has contact with a supply line, or the sensor element itself has failed. There is no public manufacturer description of P2B46; NTN-SNR lists it simply as inlet sensor B, second bank, signal too high. On engines like the Mercedes M176/M177, whose CAMTRONIC actuators have the sensor built in, replacing the actuator is the usual repair once the wiring checks out. With the feedback lost, the engine control keeps the cam lift in its default position, so drivers mostly notice the warning lamp and a little more fuel use. Bank 1 counterpart: P2B42.

Likely causes

Sensor ground interrupted
Signal line in contact with a supply line
Sensor element in the actuator failed

Symptoms

  • Check engine light on
  • Cam lift held in default position on bank 2
  • Slightly increased fuel consumption

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

a camshaft position actuator pos sensor b b2wiring harnessecm

Related codes

P2B42P2B43P2B44P2B45P2B4EP34B3

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