Brake Fluid Level Warning Switch

A fluid level switch is incorporated into the reservoir cap.

• With sufficient fluid level the reed contact is closed
• When level drops below allowable limits, switch opens.

Since the normal position is closed, this circuit is monitored for shorts to + and ground.

The ABS ECU monitors the fluid level and issues a low fluid level message on the CAN.

The LCM receives the message and illuminates the warning lamp and generates the low brake fluid message for the message center. If the ground signal is momentary, the LCM signals the Instrument cluster of the condition. The instrument cluster then informs the ABS ECU over the CAN bus. If the signal is received prior to the activation of the pre-charge pump, the pre-charge pump activation is delayed.

If the signal is present for more then 25 seconds, the LCM issues two I BUS messages for the Instrument Cluster:

• Post "Brake Fluid Level "in the Message center
• Notify the ABS via CAN that the Fluid level has been low for more than 25 seconds.

The ABS ECU immediately switches DSC functions off and continuously illuminates the DSC indicator in the cluster.