Faulty camshaft position actuator position sensor on bank 2; Open or shorted signal circuit in the sensor wiring harness; Corroded or damaged electrical connector at the sensor or PCM; Failed camshaft position actuator solenoid or phaser mechanical issue; PCM internal fault or software calibration issue; Contamination or debris interfering with the sensor reluctor wheel

DTC codes / P34xx · Auxiliary emission controls / P34B3

P34B3A Camshaft Position Actuator Position Sensor A Circuit High Bank 2

P34B3 indicates that the powertrain control module has detected an abnormally high voltage on the signal circuit of the camshaft position actuator position sensor for bank 2, sensor A. This high voltage reading tells the computer that the sensor circuit is likely open, shorted to power, or that the sensor itself has failed, preventing accurate feedback on camshaft phaser position.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or unstable engine operation, especially when cold
Reduced engine power or limp mode under certain conditions
Poor fuel economy or increased emissions
Intermittent stalling or difficulty starting
Unusual engine noises from the valvetrain area due to incorrect camshaft timing

Common causes, most likely first

Faulty camshaft position actuator position sensor on bank 2
Open or shorted signal circuit in the sensor wiring harness
Corroded or damaged electrical connector at the sensor or PCM
Failed camshaft position actuator solenoid or phaser mechanical issue
PCM internal fault or software calibration issue
Contamination or debris interfering with the sensor reluctor wheel

How to diagnose and fix it

Perform a visual inspection of the sensor, connector, and wiring for damage or corrosion
Use a scan tool to check live data for the camshaft position actuator sensor voltage and compare to specifications
Test the sensor signal circuit for continuity and shorts to power or ground using a multimeter
Check the sensor's reference voltage and ground circuits at the connector
Replace the camshaft position actuator position sensor if testing indicates it is faulty
Repair any damaged wiring or connectors and clear the diagnostic trouble codes
Verify the repair by test-driving the vehicle and confirming the code does not return

Common misdiagnosis traps for P34B3

A high voltage code is often caused by a simple open circuit in the wiring rather than a failed sensor, so always check continuity before replacing parts.
The camshaft position actuator position sensor is sometimes confused with the camshaft position sensor itself, but they serve different functions and have different part numbers.
Oil sludge or debris can accumulate on the sensor tip and cause erratic readings that mimic an electrical fault, so cleaning the sensor may resolve the issue.
In some vehicles, a failing camshaft phaser or solenoid can cause the sensor to read out of range, setting this code even though the sensor is good.
After repairs, the PCM may require a relearn procedure for the camshaft actuator to ensure proper timing and prevent code recurrence.

Can I keep driving with P34B3?

It is generally safe to drive with this code if the engine is running smoothly, but avoid aggressive acceleration or heavy loads until diagnosed. If the engine runs rough, stalls, or enters limp mode, seek professional repair promptly to prevent further damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.