Defective HCU. 2015 Ram 3500 single rear wheel 4 wheel drive with 40,000 miles. ABS light, ESC/Traction Control codes and dingers started in 2020 at 28,000 miles. DTC code indicates defective HCU. Several dealerships have been unable to address repairs due to updated parts unavailable from FCA. This vehicle with known defective braking system has been restricted to local errands for 4+ years for safety reasons while family camper remains stored.