Circuit/System Testing

WARNING: This page is about a different car, the 2018 Cadillac XTS. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Circuit/System Verification must be performed before Circuit/System Testing.

Ignition OFF, disconnect the harness connector at the B87 Rearview Camera.
Test for less than 10 Ω between the ground circuit terminal 5 and ground.
- If 10 Ω or greater
  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
Ignition ON.
Verify a test lamp illuminates between the ignition circuit terminal 6 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF.
2. Test for less than 2 Ω in the ignition 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 OK and there is voltage at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the ignition circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance, test or replace the KR73 Ignition Main Relay.
- Go to next step: If the test lamp illuminates
Engine running, park brake applied, transmission in REVERSE.
Verify a test lamp illuminates between the control circuit terminal 3 and ground.
- If the test lamp does not illuminate
1. Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module and remove both E5 Backup Lamps.
2. 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
3. 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.
- Go to next step: If the test lamp illuminates
Ignition OFF, disconnect the X2 harness connector at the K74 Human Machine Interface Control Module, ignition ON.
Test for less than 1 V between the signal circuit terminal listed below and ground:
- Signal (+) circuit terminal 1 at the B87 Rearview Camera.
- Signal (-) circuit terminal 4 at the B87 Rearview Camera.
- If 1 V or greater
  Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Test for infinite resistance between the signal circuit terminal listed below and ground:
- Signal (+) circuit terminal 1 at the B87 Rearview Camera.
- Signal (-) circuit terminal 4 at the B87 Rearview Camera.
- 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 signal (+) circuit end to end.
- If 2 Ω or greater
  Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
Test for less than 2 Ω in the signal (-) circuit end to end.
- If 2 Ω or greater
  Test the signal circuit for an open/high resistance.
- Go to next step: If less than 2 Ω
Replace the B87 Rearview Camera.
Engine running, parking brake applied, transmission in REVERSE, verify a clear rear vision image is displayed on the A11 Radio.
- If a clear rear vision image is not displayed on the A11 Radio
  Replace the K74 Human Machine Interface Control Module.
- Go to next step: If a clear rear vision image displayed on the A11 Radio
All OK.