Powertrain, shared range

P34B6 B Camshaft Position Actuator Temperature Sensor Circuit Low Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Circuit Low means the voltage on the signal wire of the exhaust actuator B temperature sensor (bank 1) stays under its lower limit. Which temperature that stands for depends on a sensor curve that no public source gives; with a thermistor whose resistance falls as it warms, a short to ground would look like extreme heat. Aisin's patent shows what a hot reading triggers: the controller lowers the motor current and may even switch the motor off at a preset threshold, so exhaust phasing loses authority. In the NTN-SNR catalogue P34B6 appears as an undersized outlet-side signal. Wires rubbing on the cylinder head and a sensor shorted inside are the main suspects. No carmaker documents P34B6. High: P34B7; bank 2: P34BA.

Likely causes

Signal wire chafed through and touching ground
Sensor element shorted inside the actuator
Actuator driver genuinely overheated by a binding phaser

Symptoms

  • Malfunction indicator lamp lit
  • Exhaust phasing on bank 1 reduced, slightly rougher idle possible

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–800
Time0.5–3 h

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

Parts involved

cam actuator b temp sensor b1sensor wiring

Related codes

P34B4P34B5P34B7P34BAP34A6

References: law.cornell.edu, ntn-snr.com, patents.google.com.