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P0537

A/C Evaporator Temperature Sensor Circuit Low

The evaporator temperature sensor signal voltage is below the lower diagnostic threshold. Indicates a short to ground or sensor fault.

  • Check engine light: Not always
  • Emissions related: No
  • Repair difficulty: easy

Common causes

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

  • Sensor internally shortedCommon
  • Signal wire shorted to groundPossible
  • Connector pins corroded - high contact resistanceLess likely

Parts involved

  • AC Evaporator Temp Sensor
  • Sensor Wiring

P0537 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.