Circuit/System Testing

WARNING: This page is about a different car, the 2020 Buick Regal TourX, 2020 Buick Regal, 2019 Buick Regal TourX, and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.

Use the wiring schematics to identify the items/configurations listed below:
- Brake Pedal Position Sensor Signal @ K20 Engine Control Module
Ignition/Vehicle & All vehicle systems - Off
Disconnect the component: K20 Engine Control Module
Ignition - On/Vehicle - In Service Mode
Connect a test lamp between the test points: Brake Pedal Position Sensor Signal & Ground
Slowly press and release the brake pedal.
Verify the test lamp turns On and Off.
- If the test lamp is always Off
1. Ignition/Vehicle & All vehicle systems - Off
2. Disconnect the component: K9 Body Control Module
3. {If equipped} Disconnect all components on the circuit: Brake Pedal Position Sensor Signal
4. Test for infinite resistance between the test points: Signal circuit terminal 12 @ K9 Body Control Module X5 & Ground
  - If less than infinite resistance - Repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
5. Test for less than 2 ohms between the test points: Signal circuit terminal 12 @ K9 Body Control Module X5 & The other end of the circuit
  - If 2 ohms or greater - Repair the open/high resistance in the circuit.
  - If less than 2 ohms - Replace the component: K9 Body Control Module
- If the test lamp is always On
1. Ignition/Vehicle & All vehicle systems - Off
2. Disconnect the component: K9 Body Control Module
3. Ignition - On/Vehicle - In Service Mode
4. Test for less than 1 V between the test points: Signal circuit terminal 12 @ K9 Body Control Module X5 & Ground
  - If 1 V or greater - Repair the short to voltage on the circuit.
  - If less than 1 V - Replace the component: K9 Body Control Module
- Go to next step: If the test lamp turns On and Off
Replace the component: K20 Engine Control Module