Coolant Temperature

Powertrain Control Module (PCM) uses Class 2 serial data communications in order to inform the Instrument Panel Cluster (IPC) of engine coolant temperature. IPC operates temperature gauge in order to appropriately display engine coolant temperature. PCM determines coolant temperature by measuring signal voltage from a variable resistance sensor in the engine coolant jacket when ignition switch is in RUN position. As coolant temperature increases, sensor resistance decreases.