Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2015 GMC Yukon XL, 2015 GMC Yukon, 2015 Chevrolet Tahoe, 2015 Chevrolet Suburban, and 2015 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF and all vehicle systems OFF, disconnect the X2 harness connector at the K157 Video Processing Control Module. It may take up to 2 min for all vehicle systems to power down.
- Test for less than 10 Ω between the ground circuit terminal 7 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.
- If less than 10 Ω
- Ignition ON.
- Verify a test lamp illuminates between the ignition circuit terminal 1 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF.
- 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 (With BTM)Power Mode Mismatch (Without BTM) .
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF.
- 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 K157 Video Processing Control Module.
- If the test lamp illuminates
- Test for 1-4.5 V between the serial data circuit terminal 3 and ground.
- If less than 1 V or greater than 4.5 V
Refer to Scan Tool Does Not Communicate with Low Speed GMLAN Device
- If between 1-4.5 V
- If less than 1 V or greater than 4.5 V
- 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 terminals listed below and ground:
- K74 Human Machine Interface Control Module signal (+) circuit terminal 5 X2
- K74 Human Machine Interface Control Module signal (-) circuit terminal 6 X2
- If 1 V or greater
Repair the short to voltage on the circuit.
- If less than 1 V
- Test for infinite resistance between the signal circuit terminals listed below and ground:
- K74 Human Machine Interface Control Module signal (+) circuit terminal 5 X2
- K74 Human Machine Interface Control Module signal (-) circuit terminal 6 X2
- If less than infinite resistance
Repair the short to ground on the circuit.
- If infinite resistance
- Test for less than 2 Ω between the K74 Human Machine Interface Control Module signal (+) circuit terminal 5 X2 and the K157 Video Processing Control Module signal (+) circuit terminal 6 X2.
- If 2 Ω or greater
Repair the open/high resistance on the circuit.
- If less than 2 Ω
- If 2 Ω or greater
- Test for less than 2 Ω between the K74 Human Machine Interface Control Module signal (-) circuit terminal 6 X2 and the K157 Video Processing Control Module signal (-) circuit terminal 12 X2.
- If 2 Ω or greater
Repair the open/high resistance on the circuit.
- If less than 2 Ω
- If 2 Ω or greater
- Replace the K157 Video Processing Control Module.
- Engine running, 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.
- If a clear rear vision image is displayed
- If a clear rear vision image is not displayed
- All OK.