Pcm Code E15, Open Coolant Sensor CKT: Description

Coolant sensor is a thermistor (temperature-sensitive resistor). Sensor uses a 2-wire harness. Sensor signal voltage comes from PCM to terminal "B" on circuit No. 410. Sensor reference ground comes to terminal "A" from PCM on circuit No. 476.

As temperature of sensor increases, sensor resistance decreases. High coolant temperature will result in low signal voltage on circuit No. 410. PCM Code E15 then sets because coolant temperature cannot be less than -36°F (-38°C) when MAT is 23°F (-5°F).