Circuit/System Testing
WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
Brake Pedal Position Sensor Malfunction
- Ignition OFF, disconnect the harness connector at the B22 Brake Pedal Position Sensor, ignition ON.
- Test for less than 1 V between the low reference circuit terminal 2 and ground.
- If 1 V or greater
- Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
- Test for less than 1 V between the low reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K9 Body Control Module.
- Go to next step: If less than 1 V
- Test for B+ between the low reference circuit terminal 2 and B+.
- If less than B+
- Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module.
- Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- Go to next step: If B+
- Test or replace the B22 Brake Pedal Position Sensor.
Stop Lamps Malfunction
- Ignition OFF, disconnect the X1 harness connector at the K9 Body Control Module, ignition ON.
- Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the F8DA fuse from the X51A Fuse Block - Instrument Panel.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF, remove the F8DA fuse from the X51A Fuse Block - Instrument Panel.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K9 Body Control Module.
- Go to next step: If the test lamp illuminates
- Verify a test lamp illuminates between the B+ circuit terminal 2 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the F9DA fuse from the X51A Fuse Block - Instrument Panel.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF, remove the F9DA fuse from the X51A Fuse Block - Instrument Panel.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K9 Body Control Module.
- Go to next step: If the test lamp illuminates
- Ignition OFF, connect the X1 harness connector at the K9 Body Control Module.
- Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate E43 Liftgate Tail Lamp Assembly.
- Test for less than 10 Ω between the ground circuit terminal A and ground.
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 10 Ω
- Connect a test lamp between the control circuit terminal C and ground, ignition ON.
- Verify the test lamp turns ON and OFF when commanding the appropriate Stop Lamp ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module.
- X4 left stop lamp
- X5 right stop lamp
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the appropriate harness connector listed below at the K9 Body Control Module, ignition ON.
- X4 left stop lamp
- X5 right stop lamp
- Test for less than 1 V between the control circuit terminal and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K9 Body Control Module.
- Go to next step: If the test lamp turns ON and OFF
- Test or replace the E43 Liftgate Tail Lamp Assembly.
Stop Lamp Malfunction - Auxiliary
- Ignition OFF, exterior lamps OFF, remove the appropriate E5 Tail/Stop Lamp - Auxiliary bulb.
- Test for less than 10 Ω between the ground circuit at the socket terminal and ground.
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 10 Ω
- Connect a test lamp between the control circuit at the socket terminal and ground, ignition ON
- Verify the test lamp turns ON and OFF when commanding the appropriate E5 Tail/Stop Lamp - Auxiliary ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the X3 harness connector at the K23 Folding Top Control Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K23 Folding Top Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the X3 harness connector at the K23 Folding Top Control Module, ignition ON.
- Test for less than 1 V between the control circuit terminal and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K23 Folding Top Control Module.
- Go to next step: If the test lamp turns ON and OFF
- Test or replace the appropriate E5 Tail/Stop Lamp - Auxiliary.
Center High Mount Stop Lamp Malfunction
- Ignition OFF, exterior lamps OFF, trunk latch latched, disconnect the harness connector at the E6 Center High Mounted Stop Lamp.
- Test for less than 10 Ω between the ground circuit terminal 1 and ground.
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.
- Go to next step: If less than 10 Ω
- Connect a test lamp between the control circuit terminal 2 and ground, ignition ON.
- Verify the test lamp turns ON and OFF when commanding the Center Stop Lamp ON and OFF with a scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
- Test for less than 1 V between the control circuit terminal and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K9 Body Control Module.
- Go to next step: If the test lamp turns ON and OFF
- Test or replace the E6 Center High Mounted Stop Lamp.