Code U0153 on the 2020 Mercedes-Benz GLC indicates lost communication with door control module 'A', typically the driver's door module. This module controls door-specific functions including the window, lock, mirror, and various switches.
Door Module Functions
Mercedes door modules are sophisticated controllers that manage power windows, door locks, mirror adjustment and heating, ambient lighting, seat memory buttons (on driver's door), and communicate status to the central body electronics. Each door has its own module connected via the vehicle's CAN network.
Door Function Loss
With U0153 present, functions on the affected door may not work. The power window may be inoperative, the door lock may not respond to commands, mirror adjustment may fail, and door-mounted controls may not function. Additionally, the central electronics lose status information about that door's condition.
Diagnostic Path
Door module 'A' is typically the driver's door. The module is located inside the door panel. Check the door jamb wiring first - this is the most common failure point as wires flex each time the door opens. Verify power and ground reach the module. Test CAN communication through the door harness.
Repair Considerations
Door jamb wiring failures are extremely common. Inspect carefully and repair any broken wires. If the module itself has failed (less common), replacement requires Mercedes XENTRY for coding and personalization features like seat memory.