Powertrain, generic (extended)

P2B41 A Camshaft Position Actuator Position Sensor B Circuit Low Bank 1

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2B41 reports a voltage below the permitted window from sensor B, which watches the intake actuator of bank 1. That usually points to a grounded signal line or a sensor that has failed internally. Mercedes describes the matching low fault on the exhaust side (P34BE, sensor of CAMTRONIC solenoid 1) literally as a short to ground, which shows how the family is meant; a public text on P2B41 itself is not known. GM's L3B, used here only as a comparison, sets its low codes on the sliding cam (P2C07) at 0.5 Ω or less between signal and ground while the driver is on, after 4 of 5 samples with more than 11 V supply. Chafed harness sections over the cylinder head deserve the first look. High is P2B42.

Likely causes

Signal wire shorted to ground (chafed harness)

Sensor shorted internally

Sensor supply interrupted

Symptoms

Check engine light on
Cam lift switching disabled
Possibly further codes from sensors on the same supply

Repair estimate

DifficultyMediumDIY possible

Parts and labour€60–600

Time0.5–3 h

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

Parts involved

a camshaft position actuator pos sensor b b1wiring harnessecm

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