U029CLost Communication With Drive Motor Control Module D
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- Letter D refers to the controller of a fourth drive motor, which presupposes individual-wheel drive. Rivian's quad-motor R1S is the familiar production case: each wheel gets its own frame-mounted Bosch motor, so torque can be split freely between all four corners at any time. U029C says module D has gone silent on the network. If it still sent frames with bad content, U059D would be stored instead; a silent third motor is U029B. No manufacturer documents U029C publicly, so which wheel letter D belongs to and how the car reacts are vehicle-specific. CARB 1968.2 obliges hybrid OBD systems to notice when a digital input stops communicating. A plausible response is to drop the silent motor, cap the torque on the other side so the car still runs straight, and warn of reduced power.
- What you may notice
- Reduced power and loss of torque vectoring
- Drive system warning in the cluster
- Uneven traction when accelerating
- Likely causes
- PossibleFuse, low-voltage supply or ground of module D faulty
- PossibleBus wiring near the wheel drive unit chafed or wet
- RareSoftware fault or failed update of module D
- RareDrive motor control module D internally failed
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.