Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Brake Warning Lamp
The brake control module (BCM) (4/16) informs the driver information module (DIM) (5/1) if there is a fault in the brake system. The driver information module (DIM) informs the driver by lighting warning lamps and also displaying a text message. The signal is transmitted from the brake control module (BCM) (4/56) to the central electronic module (CEM) on the high speed section of the control area network (CAN). The central electronic module (CEM) transmits the signal onwards on the low speed section of the controller area network (CAN) to the driver information module (DIM).
The brake fluid level sensor detects the level of the brake fluid in the reservoir. The switch in the sensor closes again when the level is low. A signal is then transmitted from the brake control module (BCM), via the central electronic module (CEM), to the driver information module (DIM), which lights the red warning lamp and the brake warning lamp. The driver information module (DIM) also displays a text message.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.