Powertrain, shared range

P34BE B Camshaft Position Actuator Position Sensor A Circuit Low Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

For P34BE, too, a Mercedes-Benz text exists: the CAMTRONIC bulletin covering the M176 and M177 eight-cylinders reads P34BE00 as the signal of exhaust solenoid 1, bank 1, being grounded. That fits the generic meaning, a signal under its lower limit. Mercedes points to the engine cover and the wiring routed over the bulkhead, close to the windshield, where heat damage was found; harness damage is to be reported with photos and a lambda graph test. Beyond the wiring, the remedy includes fitting the latest CAMTRONIC actuators and updating the engine software. Once the feedback is lost the system can enter limp-home (P164B), and the exhaust cam profile of that bank stays fixed. High on bank 1: P34BF; low on bank 2: P34C2.

Likely causes

Heat-damaged harness above the bulkhead, signal shorted to ground
Sensor inside the CAMTRONIC actuator shorted (older part number)
Engine control software not up to date

Symptoms

  • Check engine light on
  • CAMTRONIC limp-home, exhaust valve lift on bank 1 no longer switched

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time1–5 h

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

Parts involved

cam actuator b pos sensor b1sensor wiring

Related codes

P34BCP34BDP34BFP34C2P2B49

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