Powertrain, generic (extended)

P2B45 A Camshaft Position Actuator Position Sensor B Circuit Low Bank 2

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P2B45 means the bank 2 intake actuator's position sensor B delivers an unusually low voltage – on bank 2, which a V engine places opposite cylinder 1. A grounded signal wire is the classic cause; an internally shorted sensor or a missing supply gives the same picture. Mercedes words the low faults of this family on CAMTRONIC V8s as a ground short (P34BE and P34C2, exhaust sensor A), though P2B45 itself appears in no public manufacturer text. Because the Mercedes bulletin on these engines found heat-damaged harnesses behind the engine, that area belongs on the check list. CARB requires out-of-range low signals of such sensors to be detected. Circuit High on the same bank is P2B46.

Likely causes

Signal wire grounded through chafing or heat damage

Sensor in the actuator shorted

Supply to the sensor missing

Symptoms

Check engine light on
Lift change on bank 2 stops working
Possibly limp-home message

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

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