LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 2019 >> CTS Base, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 130 (Image Display Camera System) >> Diagnostic Information and Procedures >> Rear Vision Camera System Malfunction (with IO5 or IO6) >> Circuit/System Testing
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Cadillac CTS. 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.
  • Under normal operating conditions the Human Machine Interface Control Module will become very hot. The module should be allowed to cool down prior to removal for any service procedure.
  1. Ignition OFF, disconnect the harness connector at the B87 Rearview Camera.
  2. Test for less than 10 Ω between the ground circuit terminal 5 and ground.
    • If 10 Ω or greater 
    1. Ignition OFF.
    2. 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 
  3. Ignition ON.
  4. 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. Refer to Power Mode Mismatch .
    • 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, replace the B87 Rearview Camera.
    • Go to next step: If the test lamp illuminates 
  5. Engine running, parking brake applied, transmission in REVERSE.
  6. Test for greater than 11 V between the control circuit terminal 3 and ground.
    • If less than 11 V 
    1. Ignition OFF, disconnect the X7 harness connector at the K9 Body Control Module.
    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 greater than 11 V 
  7. Ignition OFF, disconnect the K74 Human Machine Interface Control Module X1 harness connector. Ignition ON.
  8. Verify a test lamp illuminates between serial data communication enable circuit terminal 5 and ground.
    • If the test lamp does not illuminate 
    1. Ignition/Vehicle OFF.
    2. Test for infinite resistance between the serial data communication enable 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 serial data communication enable circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the control module that controls the serial data communication enable circuit.
    • Go to next step: If the test lamp illuminates 
  9. Ignition OFF, Connect the K74 Human Machine Interface Control Module X1 harness connector.
  10. Disconnect the X2 harness connector at the K74 Human Machine Interface Control Module, ignition ON.
  11. Test for less than 1 V between the signal circuit terminal listed below and ground:
    • B87 Rearview Camera signal (+) circuit terminal 1
    • B87 Rearview Camera signal (-) circuit terminal 4
    • If 1 V or greater 

      Repair the short to voltage on the circuit.

    • Go to next step: If less than 1 V 
  12. Test for infinite resistance between the signal circuit terminal listed below and ground:
    • B87 Rearview Camera signal (+) circuit terminal 1
    • B87 Rearview Camera signal (-) circuit terminal 4
    • If less than infinite resistance 

      Repair the short to ground on the circuit.

    • Go to next step: If infinite resistance 
  13. 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 
  14. 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 
  15. Replace the B87 Rearview Camera.
  16. Engine running, parking brake applied, transmission in R, verify a clear rear vision image is displayed on the P17 Info Display Module.
    • If a clear rear vision image is not displayed 

      Replace the K74 Human Machine Interface Control Module.

    • Go to next step: If a clear rear vision image is displayed 
  17. All OK.
scientia non olet · About LEMON Manuals