2021 Land Rover Discovery Powertrain & Transmission Problems

I am filing a safety complaint regarding a sudden and complete loss of power event while driving my 2021 Land Rover Discovery. The vehicle experienced a DC-DC converter failure with no warning, resulting in a sudden shutdown. The engine lost power, critical systems went offline, and I was unable to shift the vehicle into neutral. The vehicle became immobilized in active traffic, creating a dangerous situation. This incident occurred without warning and left me with no ability to safely move the vehicle out of traffic or rely on normal emergency functions. This presents a serious safety hazard to both the driver and others on the road. The vehicle has been at the dealership since mid-January 2026. The dealer has stated that the DC-DC failure caused additional component failures. However, no root cause has been identified beyond “internal failure,” and I have not been provided confirmation that the system has been properly tested or that the issue will not recur. I am concerned that this failure can cause cascading electrical issues, including loss of the 12V system, impacting multiple critical vehicle functions at once. The lack of a clear diagnosis and verified repair raises concerns about reliability and safety. Given the sudden loss of power, inability to move the vehicle, and absence of a confirmed root cause or validated repair, I am formally requesting that the National Highway Traffic Safety Administration open a defect investigation into the MHEV/DC-DC system. This failure creates a significant safety risk, including vehicles becoming immobilized in active traffic without warning. The risk of recurrence without a defined cause is especially concerning and may indicate a broader issue.

This is an update to Complaint Number 11436854, submitted on 10/14/2021, 5:53:21 PM Additional service has been performed on the vehicle to identify and correct random electrical faults interrupting the safe operations of this vehicle. Service record generated by Land Rover Boise, ID (RO Number 520844) is attached as an uploaded file. This RO indicates the third repair by Land Rover dealers that have serviced this vehicle (Lynnwood, WA; Flatirons, CO and Boise, ID) regarding the Ground Stud Update, and now provides the documentation of another ground fault in the Locking Actuator (door locks are randomly actuating w/driving).

This vehicle should be considered as a "drive at your own risk" vehicle. Engine randomly fails to start using push button start in coordination with pressing on the brake pedal. Dash and gages indicated all electrical systems were on and no warning symbols were displayed. Repeated attempts by owner to start vehicle failed. Attempts using remote start app erroneously indicated that the vehicle was already in operation. Fail-to-start generally existed for 2-4 hours before the vehicle would randomly start. Failure to start and stranding owner repeated 4 times over the next 8 days, including while the vehicle was in service shop of Dealer. Dealer service could not identify source of the problem and produced records that the safety recall for the battery ground stud issue had already been performed. Dealer service records (attached) recommended against driving vehicle due to "what seems to be intermittent high speed power train communications fault". Owner has requested Dealer By Back due to this repetitive and unresolved safety problem. Refusal from Land Rover to buy the vehicle back places this consumer safety issue back into owners hands which triggered the moral obligation to submit this information to the NHTSA as a safety problem.

Received an error message stating reduced traction only 2 wheel drive and to drive with caution. Took it to the dealer to discover the software was not programmed for the 4wd modules