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P2BB8

Engine Coolant Temperature Sensor 6 Circuit Low

The ECM detects a circuit low fault on the engine coolant temperature sensor 6. Reading cannot be used reliably for control.

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

Symptoms

  • Check engine light on
  • Cooling fan runs constantly or not at all
  • Cabin heater weak or excessively hot
  • Possible long warm-up time or hard cold start

Common causes

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

  • Signal wire shorted to groundCommon
  • Internal sensor shortPossible
  • Connector pins corroded - high contact resistanceLess likely

Parts involved

  • Engine Coolant Temperature Sensor 6
  • Wiring Harness
  • ECM

P2BB8 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.