FixVault

Code P0117, Coolant Temp. Sensor Low Temperature Indicated: Notes

ECT sensor uses a thermistor to control signal voltage to PCM. PCM applies and monitors a 5-volt reference signal to sensor. When engine coolant is cold, sensor (thermistor) resistance is high and PCM will sense a high signal voltage. As engine coolant increases, sensor resistance becomes less and PCM voltage drops.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. Determines if conditions necessary to set Code P0117 exist.
  2. Determines if sensor signal circuit is shorted to ground.