Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

Use the schematics and connector end views to identify the control module's ground, B+, ignition, and Ethernet serial data circuit terminals.

Ignition/Vehicle OFF, disconnect the harness connectors at the K124 Image Processing Module.
Verify a test lamp illuminates between each of the ground circuit terminals and B+.
- If the test lamp does not illuminate
  Repair the open/high resistance in the ground circuit or ground connection.
- Go to next step: If the test lamp illuminates
Ignition ON/Vehicle In Service Mode.
If equipped, verify a test lamp illuminates between each of the B+ circuit terminals and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Test for an open/high resistance in the B+ circuit.
  - If an open/high resistance is found, repair the fault on the circuit.
  - Go to next step: If an open/high resistance is not found
2. 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
1. Test for a short to ground in the B+ circuit.
  - If a short to ground is found, repair the fault in the circuit.
  - Go to next step: If a short to ground is not found
2. Replace the K124 Image Processing Module.
- Go to next step: If the test lamp illuminates
If equipped, verify a test lamp illuminates between each of the ignition circuit terminals, which has a fuse in the circuit, and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Test for an open/high resistance in the ignition circuit.
  - If an open/high resistance is found, repair the fault in the circuit.
  - Go to next step: If an open/high resistance is not found
2. 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
1. Test for a short to ground in the ignition circuit.
  - If a short to ground is found, repair the fault in the circuit.
  - Go to next step: If a short to ground is not found
2. Replace the K124 Image Processing Module.
- Go to next step: If the test lamp illuminates
Ignition/Vehicle OFF, disconnect the harness connectors at the K179 Automated Driving Mapping Module.
Ignition ON/Vehicle In Service Mode.
Test for less than 1 V between each of the Ethernet bus 11 circuit terminals and ground.
- If 1 V or greater
  Repair the short to voltage in the circuit.
- Go to next step: If less than 1 V
Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
Test for infinite resistance between each of the Ethernet bus 11 circuit terminals and ground.
- If less than infinite resistance
  Repair the short to ground in the circuit.
- Go to next step: If infinite resistance
Test for infinite resistance between the pair of the Ethernet bus 11 circuit terminals.
- If less than infinite resistance
  Repair the short together in the circuits.
- Go to next step: If infinite resistance
Test for less than 2 Ω in each of the Ethernet bus 11 circuits 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
Replace the K124 Image Processing Module.
Reconnect the harness connectors at the K179 Automated Driving Mapping Module.
Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
Ignition ON/Vehicle In Service Mode.
Verify DTC B1A09 does not set.
- If the DTC sets
  Replace the K179 Automated Driving Mapping Module.
- Go to next step: If the DTC does not set
All OK.