Circuit/System Verification

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:

If both DTCs U0401 and U0402 are set in the K124 Image Processing Module, the control module sending the invalid data is the K71 Transmission Control Module.

Engine running for 10 s.
Ignition ON/Vehicle In Service Mode, engine OFF, verify DTC U0400-U05FF is not set.
- If DTC U0400-U05FF is set along with other DTCs or symptoms
  Diagnose all other DTCs or symptoms first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle , or Symptoms - Vehicle .
- If DTC U0400-U05FF is set without other DTCs or symptoms
1. Program the device specified by the DTC descriptor . If the device is not programmable, replace it.
2. Verify the DTC does not set.
  - If the DTC sets, replace the appropriate device.
  - Go to next step: If the DTC does not set
3. All OK.
- Go to next step: If DTC U0400-U05FF is not set
All OK