Circuit/System Testing

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Park Brake Switch Circuit Malfunction

Ignition OFF, disconnect the harness connector at the park brake switch.
Ignition ON, verify the scan tool BCM Park Brake Switch parameter is Released.
- If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.
Install a 3A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool BCM Park Brake Switch parameter is Applied.
- If not the specified value, test the signal circuit for a short to voltage or an open/high resistance.
If all circuits test normal, test or replace the park brake switch.

Brake Fluid Level Switch Circuit Malfunction

Ignition OFF, disconnect the harness connector at the brake fluid level switch.
Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal A and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
Ignition ON, verify the scan tool IPC Brake Fluid parameter is OK.
- If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the IPC.
Install a 3A fused jumper wire between the signal circuit terminal B and the ground circuit terminal A. Verify the scan tool IPC Brake Fluid parameter is Low.
- If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.
If all the circuits test normal, test or replace the brake fluid level switch.