Engine Coolant Temperature Gauge
The engine coolant temperature gauge is an electrically driven, analogue instrument for displaying the engine coolant temperature to the driver. The pointer needle is oil damped to prevent impacts on the vehicle wheels causing deflection of the pointer needle. When the ignition is off, the pointer returns to the cold position.
The instrument pack is connected via two wires to the Engine Coolant Temperature (ECT) sensor. This sensor has a four pin connector, with the remaining two pins connected to the ECM. The ECT sensor is an NTC sensor located in the engine coolant flow. The instrument pack outputs a signal voltage to the sensor and measures the returned signal. The sensor resistance falls as the coolant temperature increases. The instrument pack microprocessor evaluates the returned signal and converts the information into an output drive to position the temperature gauge needle at the appropriate position. The engine coolant temperature is available for use by other vehicle systems via the CAN.
The following table shows coolant temperature relationship to gauge needle pointer position.
| Coolant Temperature | Gauge Needle Pointer Position |
|---|---|
| 15.00°C (59.00°F) | At beginning of blue segment |
| 50.25°C (122.45°F) | At end of blue segment |
| 95.25°C (203.45°F) | At center of display |
| 126.00°C (258.80°F) | At center of red segment |
The engine coolant temperature gauge is the same on all pack variants. The gauge display has a blue segment for low temperatures and a red segment for excessively high temperatures. For normal engine operating temperatures the gauge needle pointer is positioned centrally in the gauge display zone.