GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2002 🢒 Express 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Brake Warning System Description and Operation

Brake Warning System Description and Operation DRL Equipped

Brake Warning Indicator

The Brake Warning Indicator illuminates when the when one or more of the following occurs:

    • The EBCM performs the bulb check. The EBCM applies ground to the ABS pressure differential sensor signal circuit.
    • The brake pressure differential switch is closed by a pressure differential between the front and rear brake circuits. The brake pressure differential switch applies ground to the ABS pressure differential sensor signal circuit.
    • The power brake booster fluid flow and pressure are detected as being low (w/UJ1 Only). The power brake booster fluid pressure and fluid flow alarm switches both close, applying ground to the brake fluid level sensor signal circuit. In turn, the P/B Booster Fluid Flow And Pressure Alarm Delay Module applies ground to the brake warning indicator supply voltage 2 circuit. The power brake booster fluid flow alarm also sounds when this occurs.
    • The park brake is engaged. The park brake warning switch applies ground to the park brake switch signal circuit. In turn, the Daytime Running Lamps (DRL) Control Module applies ground to the brake warning indicator control circuit.
    • The ignition is turned to START. The ignition switch applies ground to the park brake switch signal circuit. In turn, the DRL Control Module applies ground to the brake warning indicator control circuit.

Brake Warning System Description and Operation Without DRLs

Brake Warning Indicator

The Brake Warning Indicator illuminates when the when one or more of the following occurs:

    • The EBCM performs the bulb check. The EBCM applies ground to the ABS pressure differential sensor signal circuit.
    • The brake pressure differential switch is closed by a pressure differential between the front and rear brake circuits. The brake pressure differential switch applies ground to the ABS pressure differential sensor signal circuit.
    • The power brake booster fluid flow and pressure are detected as being low (w/UJ1 Only). The power brake booster fluid pressure and fluid flow alarm switches both close, applying ground to the brake fluid level sensor signal circuit. In turn, the P/B Booster Fluid Flow And Pressure Alarm Delay Module applies ground to the brake warning indicator supply voltage 2 circuit. The power brake booster fluid flow alarm also sounds when this occurs.
    • The park brake is engaged. The park brake warning switch applies ground to the brake warning indicator control circuit.
    • The ignition is turned to START. The ignition switch applies ground to the brake warning indicator control circuit.