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Coolant level sensor

Coolant level sensor





General

The coolant level sensor consists of a round magnetic float which moves up and down along a hollow column attached to the bottom of the expansion tank. The sensor sits in the hollow column on the outside of the tank and is affected by the magnet.

The SID unit sends B+ to the level sensor via pin 18 and the sensor is grounded at grounding point G40. At normal level, the float arm is level with the switch, the magnet in the float arm closes the circuit and pin 18 of the SID unit is grounded. At low level, the circuit to ground is broken.

The function generates a CHECK message in the SID (30 seconds delay).

Diagnostics

If the circuit to the coolant level sensor is broken, the text message “FILL COOLANT FLUID” will be shown despite a correct coolant level.

If a short-circuit to ground occurs, the CHECK message will not be shown even if the coolant level is low.

The SID unit will not generate a diagnostic trouble code.