A used electric car bargain can sometimes hide an expensive surprise. That is exactly what happened when one owner picked up a high-spec Tesla sedan for the price of a cheap used commuter. What followed turned into a fascinating deep dive into DIY electric vehicle repair and a reminder that dealer quotes are not always the final answer.
The car in question was an early Tesla Model S that originally carried a window sticker north of $140,000 before taxes. It had every major option available at the time, including the once famous Ludicrous Speed upgrade that alone cost $10,000.
A decade later, the luxury EV had depreciated dramatically. The owner managed to buy the entire car for just $10,300.
That price may sound like a steal, but older Teslas come with two well-known risks. If the main high voltage battery fails, or if a drive motor dies, the repair bill can exceed the value of the car itself. For many owners, those failures effectively total the vehicle.
The Warning Light That Changed Everything
For several months the car drove just fine. Then one day a warning appeared on the dashboard. The message indicated a problem with the front drive motor.
At first the owner ignored it because the car still drove normally and made no unusual noises. Unfortunately, the warning quickly returned on the next drive, this time disabling the front motor entirely.
The difference was obvious. With only the rear motor providing power, the all-wheel drive performance sedan suddenly felt sluggish.
A quick consultation with a friend who has experience dismantling older Teslas produced grim advice. The easiest solution, he said, was simply to sell the car and take the loss. The likely fix would require a full front motor replacement.
To confirm the diagnosis, the owner contacted Tesla through the company’s service app. One interesting feature of Tesla vehicles is that technicians can remotely access vehicle data and generate a repair estimate without physically inspecting the car.
The estimate confirmed the friend’s suggestion. Tesla recommended replacing the entire front drive motor at a cost of more than $5,500. For a car worth only around ten thousand dollars, that repair made little financial sense.
A YouTube Video Saved the Day
Instead of giving up, the owner began searching for alternatives. Eventually a video from the EV repair-focused YouTube channel Out of Spec Renew provided a crucial clue. The host explained that a common failure on some Model S vehicles is not the motor itself, but a small encoder sensor that monitors motor speed.
If the sensor fails, the car disables the motor because it no longer receives accurate feedback.
Replacing the sensor through the conventional method would require removing the entire drive unit. However, the video revealed a clever workaround. By dropping the large battery pack from the underside of the car, it becomes possible to access the traction inverter and reach the sensor from behind.
That discovery kicked off a serious garage project.
The $70 Fix That Saved Thousands
The repair began with disconnecting the low voltage battery and removing safety connectors that isolate the high voltage system.
After that, dozens of bolts holding the enormous battery pack were carefully removed. The pack weighs roughly 1,200 pounds, so a wheeled platform was positioned underneath to support it as the lift slowly lowered the car away from the battery.
Once the battery was on the ground, the inverter housing could finally be opened.
During disassembly a plastic connector accidentally snapped, but a replacement was quickly 3D printed using a file shared online by another Tesla owner who had made the same mistake.
With the inverter cover removed, the faulty encoder sensor was visible. Surprisingly, the replacement part did not even come from Tesla. It came from the electric version of the Mercedes-Benz compact crossover, specifically the Mercedes-Benz B-Class Electric Drive, which used Tesla supplied drivetrain components. The sensor cost just $70.
Back on the Road
Installation took only moments. After reassembling the inverter and carefully raising the battery pack back into position, the car was powered on.
The moment of truth arrived when the wheels began spinning freely on the lift with no warning lights on the dashboard. After addressing a small coolant valve leak and replacing a burned-out headlight bulb, the owner took the car for a road test.
Ten miles later the warning never returned. The front motor was fully operational again.
Ultimately, what Tesla estimated as a $5,500 motor replacement ended up being solved with a $70 sensor and a weekend of hands-on work. For owners willing to learn and turn a wrench, older Teslas apparently still offer remarkable value.
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