Coolant Temperature

Vehicle Control Module/Powertrain Control Module (VCM/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/VCM determines coolant temperature by measuring signal voltage from a variable resistance sensor in the engine coolant jacket with ignition switch in RUN position. As coolant temperature increases, sensor resistance decreases.