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P01B9

Engine Oil Temperature Sensor B Circuit

Generic electrical fault on engine oil temperature sensor B (second sensor for redundancy or different measurement location).

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

Common causes

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

  • Sensor failedCommon

Parts involved

  • Oil Temp Sensor B
  • Sensor Wiring

P01B9 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.