Circuit/System Testing

Ignition OFF, disconnect the appropriate harness connector listed below at the ECM:
- X1 (LF1)
- X2 (LLT)
Connect a test lamp between the appropriate signal circuit terminal listed below and ground:
- Terminal 57 (LF1)
- Terminal 52 (LLT)
Ignition ON, press and release the brake pedal. Verify the test lamp turns ON and OFF when pressing and releasing the brake pedal.
- If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
If all circuits test normal, replace the ECM.