Circuit/System Testing
- 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 (Without HP9)Power Mode Mismatch (With HP9) .
- 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.