Circuit/System Verification

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

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 set 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 set or symptoms
1. Program the device specified by the DTC descriptor.
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