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P259A

Turbocharger Boost Control Position Sensor B Performance - Stuck Low

Same condition as the A-side stuck-low fault, but on the second sensor / second turbo. Position sensor B reads stuck near the low end while the actuator is commanded.

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

Symptoms

  • Charge status indicator shows fault
  • Charging may not start or interrupts
  • Slower-than-expected charge rate

Common causes

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

  • Actuator mechanically stuck near low endCommon

Parts involved

  • Turbo Actuator Position Sensor B
  • Turbo Actuator B

P259A 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.