2017 Tesla Model S: sudden loss of power

Filed Aug 9, 2026 · Electrical · GA

2017 Tesla Model S P100D. Vehicle received a paid MCU2 infotainment upgrade (MCU1 to MCU2), which replaced both the center touchscreen computer and the instrument cluster. The original MCU1 architecture used an independent computer for the instrument cluster, providing redundancy. The MCU2 retrofit consolidated both displays onto a single processor with no fallback mode. The first MCU2 replacement unit experienced a touchscreen digitizer failure — touch input stopped responding but the displays remained powered and the instrument cluster continued to function. Tesla replaced it with a second MCU2 unit. The second MCU2 unit has experienced three complete blackout events where both the center display and the instrument cluster simultaneously lose all power — no backlight, no image, no data. One of these events occurred while driving at speed on the road. I lost all instrumentation: speedometer, gear indicator, turn signal feedback, warning lamps, backup camera, and climate controls. I had to pull over with no way to confirm my speed or signal to other drivers. The vehicle remained mechanically drivable — steering, brakes, and motor continued to function. During the recent blackout a few days back, the vehicle had been stored in a closed garage and was not heat-soaked. I have video evidence of the car with both screens completely dead while the vehicle is in gear and moving. A scroll-wheel reboot restored the screens each time. This is my fourth service visit to Tesla for this upgrade. The MCU2 architecture provides no independent fallback display for critical safety information such as speed, gear state, or warning indicators during a processor crash. The prior MCU1 system maintained instrument cluster functionality independently of the infotainment computer.

Filed Nov 13, 2025 · Electrical, Engine · CA

This is an update to the federal safety agency Complaint #XXX with new safety information. My 2017 Tesla Model S (VIN [XXX] ) has a confirmed high-voltage isolation fault. Tesla replaced the rear drive unit under warranty, but Tesla’s own technician notes now state: “There is a risk of isolation alerts reoccurring during regular driving, use of HVAC system, or DC charging.” “Vehicle may power off due to isolation faults when the air conditioning is used.” This is Tesla acknowledging in writing that the vehicle may shut off during normal driving, even after repair. This presents a serious crash risk. The original failure occurred during Supercharging, with warnings including: • “Electrical system power reduced — vehicle may shut down unexpectedly” • “Vehicle may not restart” • “Air conditioning reduced — DC charging reduced” Tesla reproduced the isolation fault during diagnosis. Even after replacing the rear drive unit, Tesla documented that the isolation defect still exists and prevents a battery health check or DC fast-charge validation. Tesla has attempted to return the vehicle to me in this unsafe condition, while admitting the defect persists. They also stated they may charge storage fees or tow the vehicle, despite the unresolved safety issue. The defect affects the HV bus and can cause loss of propulsion, shutdown during driving, and charging failure. Tesla has not provided numeric test results (megohm isolation readings, insulation tests, or validation data) proving the vehicle is safe. This is an ongoing, manufacturer-confirmed HV isolation defect that can lead to sudden power loss. I request the federal safety agency review Tesla’s handling of this issue and link this filing to Case #XXX. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Nov 5, 2025 · Electrical · CA

While charging at a Tesla Supercharger, the vehicle began making extremely loud mechanical noises on October 7, 2025, as if something inside the high-voltage system was about to explode. A warning appeared stating “Vehicle may shut down at any time.” A service request was opened the next day. Tesla scheduled the first available appointment nearly a month later, leaving the vehicle unsafe to drive. Before that appointment date, on October 31, 2025, the vehicle completely shut down at a Supercharger and could not be restarted. Tesla Roadside Assistance was dispatched three times before the car was successfully towed to a Tesla Service Center. The failure was diagnosed by the service center as a high-voltage isolation fault logged in the Battery Management System. The problem disables the vehicle suddenly and without warning, posing a serious safety hazard if it occurs while driving. Warning lamps and shutdown messages were present prior to the failure. Tesla service staff stated they could not access diagnostic data until the customer paid for unrelated parts (12-volt battery and A/C compressor). After being challenged, they later retrieved limited battery data proving that the high-voltage system had recorded faults. Tesla has not yet issued a written warranty determination or performed a full battery inspection. The incident demonstrates that a high-voltage battery isolation fault can cause the vehicle to become completely inoperable and may create risk of sudden loss of power while driving or charging. The component (battery pack and related electrical systems) remains in Tesla’s possession and can be inspected upon request.

Filed Nov 26, 2024 · Steering · NJ

The vehicle at low speed unexpectedly lost power steering making it impossible to steer. The resistance was greater than on a vehicle without power steering as if the steering mechanism was working to prevent steering. This is the second incident for me -- the first occurring in September, but immediately resolving itself.

Filed Feb 2, 2023 · Steering · IN

Sudden loss of power steering is the issue. I was driving the car home and it was about a 5 mile trip. About half way home I tried to turn left and it took all of my strength to turn the wheel. I made it around that corner and the car did the same thing when I made a right turn. It continued for two more turns and something in the steering seemed to break loose when I arrived home and steering was normal as I backed the car into the driveway. The date was 02/01/2023 at around 7:30 PM. The roads were in good condition. We had driven over some very bumpy dirt roads the weekend before. The car was giving me warnings as the steering stopped working indicating that the EPAS wasn't working and it may be harder to steer the car. I felt that it was a very dangerous situation and my safety and the safety of other drivers was at risk. No damage occurred. There were no prior warnings or messages leading up to the steering failure. The car had been in for unrelated service the month before. I do not feel it's safe to drive the car until I have am certain there is a proven fix for the issue. The software version is: 2022.8.10.8 I have scheduled service for the car on 02/7/23.

Filed Oct 18, 2022 · Acceleration, Steering · CA

This is aTesla Model S electric car. The battery was 80% charged at the time of the incident. Under normal driving at a speed of around 40 MPH in a city road road, suddenly the car lost power. The steering wheel locked and I had no control over the car. Display screen in the instrument panel and the large central tocuh screen display blacked out. A few seconds later, the car control returned and I was able to safely drive the car. But, the momentary loss of control is dangerous and scary.