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2021 Model 3 Standard Range Plus - Sudden Loss of Power and Loud Clunk

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Mike T. · rep 0 · May 25, 4:00 AM · 1 replies · solved · Question

Vehicle: 2021 Tesla Model 3 Standard Range Plus

Hello,

I was driving my 2021 Tesla Model 3 Standard Range Plus today, and suddenly, I experienced a complete and abrupt loss of power. There was a loud clunking sound, and then the car just coasted to a stop. The screen showed a critical error message, but it disappeared quickly before I could fully read it. I think it mentioned something about the 'drive unit' or 'motor fault'.

Now the car won't move at all. It's completely dead, no response when I try to put it into drive or reverse. The 12V battery seems fine, as the screen and lights are working. This happened without any prior warning signs, no strange noises or performance issues before today.

What could possibly cause such a sudden and catastrophic failure? I'm pretty shaken up. Is this a common issue for Model 3s? I've only got about 35,000 miles on it.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:00 AM

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ClearTheCode admin answer:

  1. Initial Assessment: A sudden and complete loss of power accompanied by a loud clunk, followed by the vehicle being unable to move, is a severe issue that points to a catastrophic failure within the electric drivetrain. This is not a common occurrence for a 2021 Model 3 at 35,000 miles but can happen.

  2. Common Causes for Sudden Drive Unit Failure:

    • Internal Motor Failure: This could involve a stator winding failure, rotor damage, or a catastrophic bearing failure within the main electric motor. The 'clunk' suggests a mechanical component may have broken or seized.
    • Inverter Failure: The power inverter, which controls the motor, can fail suddenly. While less likely to produce a loud 'clunk' on its own, a short circuit or component failure within the inverter could cause the motor to seize or lose power abruptly.
    • Gearbox/Reduction Gear Failure: The single-speed reduction gear assembly within the drive unit could have experienced a catastrophic failure, leading to the clunk and loss of power. This is often due to a broken gear or internal component.
    • High-Voltage Contactor Failure: The main contactors that connect the high-voltage battery to the drive unit could have failed, but this typically results in a silent power loss rather than a 'clunk.' If the contactor welded shut and then broke, it could potentially cause a noise.

  3. DIY Checks (None Recommended):

    • Given the complete loss of power and the 'clunking' sound, there are no safe or effective DIY checks you can perform. Attempting to force the vehicle into gear or repeatedly trying to start it could potentially worsen the damage or pose a safety risk.

  4. When to See a Shop:

    • Immediately (Tow Required): This situation requires immediate attention from Tesla Service. The vehicle will need to be towed to a service center. Do not attempt to drive it or force it into neutral if it's not responding. Call Tesla Roadside Assistance.

  5. Diagnostics at a Service Center: Tesla technicians will:

    • Connect to the vehicle's diagnostic system to retrieve critical error codes. Expect codes such as DRV_a001 (drive unit internal fault), DRV_a002 (motor failure), DRV_a003 (inverter fault), or similar low-level warnings indicating a major component failure.
    • Perform a thorough inspection of the drive unit, potentially involving removal and disassembly, to identify the exact point of failure (e.g., seized motor, broken gears, damaged inverter components).
    • Given the vehicle's age and mileage, it should still be covered under Tesla's 8-year/100,000-mile battery and drive unit warranty for the Standard Range Plus Model 3.
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