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P34BC

B Camshaft Position Actuator Position Sensor A Circuit Bank 1

Generic electrical fault on the position sensor of the exhaust cam actuator on bank 1. The camshaft position sensor identifies which cylinder is on the compression stroke — without it the ECM cannot run sequential injection or coil-on-plug ignition correctly.

  • Check engine light: Yes
  • Emissions related: Yes
  • Repair difficulty: hard

Symptoms

  • Check engine light on
  • Power loss especially in mid-rpm range
  • Possible rough idle or stalling
  • Increased fuel consumption

Common causes

Ordered by how often each turns out to be the cause.

  • Position sensor failedCommon

Parts involved

  • Cam Actuator B Pos Sensor B1
  • Sensor Wiring

P34BC is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.