Powertrain, shared range

P34BF B Camshaft Position Actuator Position Sensor A Circuit High Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P34BF: on bank 1, sensor A of the camshaft B actuator, i.e. the exhaust side, sends more voltage than allowed. An open ground, a signal wire in contact with a feed or an internally open sensor are the usual explanations. Mercedes-Benz documents low and implausible signals for this sensor on its CAMTRONIC V8 (P34BE, P34BD), but no high fault; other manufacturers do not mention the code either. On Mitsubishi's electric intake phaser the matching high code P34AF parks the motor in its reference position, and an electric exhaust actuator would presumably react in a similar way. CARB counts the sensors of a VVT system among the comprehensive components, whose out-of-range values must be detected. Low on bank 1: P34BE; high on bank 2: P34C3.

Likely causes

Sensor ground interrupted or plug corroded
Signal line shorted to a supply wire
Sensor in the exhaust actuator open internally

Symptoms

  • Malfunction indicator lamp lit
  • Exhaust adjustment on bank 1 kept in its reference position

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,200
Time0.5–4 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

P34BCP34BDP34BEP34C3P34AFP2B4A

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