Circuit/System Testing
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.
- Ignition OFF, disconnect the X1 harness connector at the ECM and the TCM one at a time. After each disconnect, test for current DTCs. DTC U1814 should remain current.
- If the DTC becomes history, replace the module disconnected when the DTC became history.
- Ignition OFF, disconnect the X4 harness connector at the BCM.
- Test for infinite resistance between the signal circuit terminal 19 and ground.
- If less than the specified value, test the signal circuit for a short to ground.
- If all circuits tests normal, replace the BCM.