Engine Coolant Temperature Gauge

Coolant Temperature Display

The instrument cluster receives the current coolant temperature from the engine control unit via the CAN bus. The "coolant temperature" information is then transferred to the body bus (K-bus ).

The "coolant temperature" information is evaluated by the instrument cluster and indicated by the coolant temperature gauge. The gauge is controlled in such a way as to provide approximately three indication ranges (cold, just right, too hot). If the pointer reaches the edge of the red warning segment, it is immediately moved to the center of this red warning segment.

Since, after shut-down, the engine still heats the coolant for a certain period of time, an increase in the gauge temperature when the engine is stationary is prevented by a "post-heating filter" in the software of the instrument cluster. When the engine is restarted, this function detects a higher temperature than at "engine off" and indicates this "engine off" value. The current temperature is then indicated after 20 seconds with the engine running.

The warning lamp indicating excess coolant temperature is controlled by the engine control unit via the CAN bus dependent on the pointer position of the coolant temperature gauge. The "post-heating phase" for the coolant temperature warning lamp is also monitored by the engine control unit.