| BRAKE LAMP DOES NOT ILLUMINATE |
1. Ineffective ground circuit. |
1. Test and repair open brake lamp ground circuit if required. |
| 2. Ineffective fuse. |
2. Test and replace the fuse in the BCM if required. |
| 3. Ineffective feed circuit. |
3. Test and repair open brake lamp switch output circuit or stop lamp output circuit if required. |
| 4. Ineffective switch. |
4. Test and replace brake lamp switch if required. |
| 5. Ineffective BCM inputs or outputs. |
5. Use a diagnostic scan tool to test the BCM inputs and outputs. Refer to the appropriate diagnostic information. |
| BRAKE LAMP DOES NOT EXTINGUISH |
1. Ineffective feed circuit. |
1. Test and repair shorted brake lamp switch output circuit or stop lamp output circuit if required. |
| 2. Improperly adjusted switch. |
2. Adjust the brake lamp switch if required. |
| 3. Ineffective switch. |
3. Test and replace brake lamp switch if required. |
| 4. Ineffective BCM inputs or outputs. |
4. Use a diagnostic scan tool to test the BCM inputs and outputs. Refer to the appropriate diagnostic information. |
| UNINTENDED BRAKE LAMP ACTIVATIONS |
1. Loose brake pedal due to cracked or missing bushing. This can be accompanied with Diagnostic Trouble Code (DTC) C0042-2A or P057B. |
1. Check the brake pedal for side to side looseness. If the pedal pivot bushing is cracked or missing this will change the voltage output from the brake pedal sensor. Based on this incorrect voltage, the brake pedal sensor determines the pedal is depressed when it is not. This leads to false brake lamp activations and DTCs. If the pedal pivot bushing is found on the floor, do not attempt to install it. If the pedal pivot bushing is loose or cracked, or if the pedal assembly is found to have excessive play, replace the pedal assembly must be replaced. Refer to PEDAL(S), BRAKE AND/OR ACCELERATOR, REMOVAL AND INSTALLATION
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