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P01B5

Alternative Fuel Rail Temperature Sensor Performance

Alt fuel rail temp sensor reading implausible compared to expected behavior.

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

Common causes

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

  • Sensor reading driftedCommon
  • Sensor element aged beyond calibration windowLess likely
  • Sensor element contaminated by oil, soot or coolantLess likely

Parts involved

  • Alt Fuel Rail Temp Sensor

P01B5 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.