Engine Temperature Gauge

WARNING: This page is about a different car, the 2016 Dodge Durango. However, it is still accessible from the selected car via links, so may be relevant.

The engine coolant temperature gauge gives an indication to the vehicle operator of the engine coolant temperature. This gauge is controlled by the Instrument Panel Cluster (IPC) based upon cluster programming and electronic messages received over the Controller Area Network (CAN) data bus. These electronic messages are received from the Powertrain Control Module (PCM) or Engine Control Module (ECM), depending on engine application.

The engine coolant temperature gauge is a stepper motor design unit that receives battery current on the IPC electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or START positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the OFF position. The IPC electronic circuitry controls the gauge needle position and provides the following features:

Engine Temperature Low Message - Each time the IPC receives an electronic engine temperature message from the PCM or ECM indicating the temperature is below the low end of normal [about 54 °C (130 °F), the gauge needle is held at the graduation on the far left end of the gauge scale. The gauge needle remains at the low end of the gauge scale until the IPC receives a message from the PCM or ECM indicating the temperature is above about 54 °C (130 °F), or until the ignition switch is turned to the OFF position, whichever occurs first.
Engine Temperature Message - Each time the IPC receives an electronic engine temperature message from the PCM or ECM indicating the temperature is between the low end of normal [about 54 °C (130 °F) and the high end of normal [about 122 °C (252 °F), the gauge needle is moved to the actual relative temperature position on the gauge scale.
Engine Temperature High Message - Each time the IPC receives three consecutive electronic engine temperature messages from the PCM or ECM indicating the temperature is above about 122 °C (252 °F), the gauge needle is moved to the red increment or zone at the far right end of gauge scale, the check gauges indicator is illuminated, and a single chime tone is sounded. The gauge needle remains at the high end of the gauge scale and the check gauges indicator remains illuminated until the cluster receives a message from the PCM or ECM indicating that the temperature is below about 122 °C (252 °F), or until the ignition switch is turned to the OFF position, whichever occurs first. The chime tone feature will only repeat during the same ignition cycle if the check gauges indicator is cycled OFF and then ON again by the appropriate messages from the PCM or ECM.
Communication Error - If the IPC fails to receive an engine temperature message, it will hold the gauge needle at the last indication for about 10 seconds or until the ignition switch is turned to the OFF position, whichever occurs first. After 10 seconds, the IPC will move the gauge needle to the low end of the gauge scale.

The PCM or ECM continually monitors the engine coolant temperature sensor to determine the engine operating temperature. The PCM or ECM then sends the proper messages to the IPC. For further diagnosis of the engine coolant temperature gauge or the electronic circuitry that controls the gauge. Refer to DIAGNOSIS AND TESTING . If the instrument cluster turns ON the check gauges indicator due to a high engine temperature gauge reading, it may indicate that the engine or the engine cooling system requires service.