Emergency Brake Light Warning in a Chevy C1500 Pickup
Owners of Chevy C1500 pickup trucks may sometimes be confronted with an emergency brake dashboard warning light that remains on even though the brake has been released. And when the obvious problems have been considered and ruled out, sometimes the dashboard warning light still remains illuminated.
Rule out the Obvious
Naturally, the first step is to consider the obvious reasons why that dashboard warning light keeps glowing. The most obvious culprit is the switch located immediately under the parking brake pedal. If this malfunctions, the warning light may glow even if the brake has been released. Check this first and rule it out as a possible cause.
Rear Wheel Anti-Lock Brakes May Be the Problem
This is a known issue on Chevy C1500 pickup trucks equipped with rear-wheel anti-lock (RWAL) brake systems. There is a small black module near the master cylinder that serves as the brain for this system, and there are ways to check for diagnostic trouble codes. Once a code is revealed, diagnosis can be fairly simple.
Checking the Diagnostic Trouble Codes (DTCs)
Diagnostic trouble codes (DTC) can be displayed by jumping terminal A to terminal H on the Data Link Connector and observing the flashing of the BRAKE warning light on the dashboard. This test should only be performed when the BRAKE warning lamp is glowing.
The terminals must be jumped for about 20 seconds before the code will begin to flash. Count the number of short flashes, starting from the long flash (include the long flash as a part of the count). Sometimes the first count sequence will be short. However, subsequent flashes will be accurate. If there is more than one failure, only the first recognized code will be retained and flashed.
Diagnostic Trouble Code Notes
- DTCs 6, 9, and 10 will only turn the BRAKE lamp on while the fault exists. These are soft codes faults and can only be read with the Tech 1 scan tool.
- Do not jump terminal A to terminal H if the BRAKE dashboard lamp is not on. Jumping the terminals while the BRAKE lamp is off will set a false DTC 9. This will turn the BRAKE lamp on and disable the anti-lock system.
Interpreting the Brake Lamp Code Flashes
- 1, 11, and 12: ECU (engine control unit) Malfunction
- 2: Open Isolation Valve or Malfunctioning ECU
- 3: Open Dump Valve or ECU Malfunction
- 4: Grounded Anti-lock Valve Reset Switch
- 5: Excessive Actuations of the Dump Valve
- 6: Erratic Speed Signal
- 7: Shorted Isolation Valve or Faulty ECU
- 8: Shorted Dump Valve or Faulty ECU
- 9: Open Circuit to Speed Signal
- 10: Brake Lamp Switch Circuit
- 13, 14, and 15: ECU Malfunction
With this information in hand, you should be able to either tackle the repair yourself or talk to a mechanic about making the needed fix.