Some Heat Pump Model 3 vehicles were built without a hydraulic control unit (HCU) wake-up wire, and in rare circumstances, braking and stability control related alerts may appear on the instrument cluster and touchscreen during the vehicle power-on process. Such faults can typically be corrected and the affected functionality restored with a vehicle power cycle.
full bulletin at NHTSA ↗2021 Tesla Model 3 powertrain problems
severe 15 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Complaints
15
Recalls
0
Avg fix
$2,500
2crashes
What stands out
Among the 7 model years of Tesla Model 3 in our records for powertrain problems, this one ranks #2 by owner-complaint volume.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Some Heat Pump Model 3 vehicles were built without a hydraulic control unit (HCU) wake-up wire, and in rare circumstances, braking and stability control related alerts may appear on the instrument cluster and touchscreen during the vehicle power-on process. Such faults can typically be corrected and the affected functionality restored with a vehicle power cycle.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2021 Model 3s describe two categories of powertrain hazards: sudden loss of electrical power while driving at highway speeds, and chronic misfire of the adaptive cruise control system.
On the electrical side, owners report complete power loss with battery gauges still showing 6–10% charge remaining, forcing emergency stops in traffic lanes. The high-voltage battery pack has failed twice on at least one vehicle (error code BMS_A079), both times within warranty, with the identical failure returning after Tesla replaced the pack with a remanufactured unit. A rear motor inverter has failed suddenly mid-drive with only 10–15 seconds of warning, and one dual-motor owner experienced simultaneous front and rear motor shutdown due to a power converter failure—the exact redundancy he paid for became a single point of failure. One owner's HVAC thermal management system (which cools battery and inverters) randomly shuts down due to sensor defects; Tesla issued a 2021 service bulletin promising a software fix that never materialized, now demanding paid sensor replacement.
On the cruise control front, the adaptive system phantom-brakes at highway speeds in response to highway signs it misinterprets as stopped vehicles, sometimes applying heavy braking that puts following traffic at risk. Two owners report unintended acceleration events—one at near-stationary speed, one at 29 mph—both resulting in collisions with no warning lights beforehand.
One owner's entire onboard computer rebooted while driving, rendering the speedometer, gear selector display, and cruise controls inoperative. Tesla service has declined to remedy phantom braking or investigate loss-of-power events in warranted vehicles.
Same Tesla Model 3 powertrain reports on nearby years: 2018 · 2022
Failure modes owners describe
High-Voltage Battery Pack Failure (BMS_A079)
Battery management system failure preventing charging and propulsion. Owners report the battery pack fails completely, leaving vehicles unable to charge or drive. Tesla has issued replacements, but the same failure has recurred on at least one vehicle after warranty replacement.
When: 15,100 miles and 57,222 miles (recurring failure on same vehicle); also reported at 27,000 miles
Symptoms owners cite: Vehicle will not charge; Loss of all propulsion; Battery management system error code BMS_A079 displayed; Battery gauge shows remaining charge but vehicle cannot be driven
Codes mentioned: BMS_A079
Repairs/costs cited: Tesla replaced entire high-voltage battery pack with remanufactured unit under warranty; repair performed twice on one vehicle with same failure recurring
Recalls/TSBs owners mention: Battery pack replaced under original battery warranty; Tesla has confirmed the defect and performed replacements, but recurring failure suggests unresolved root cause
Unintended Power Loss / Loss of Propulsion While Driving
Vehicle unexpectedly loses all electrical power or propulsion capability while driving at highway speeds, creating immediate safety hazard. Owners report losing power with battery charge still showing remaining capacity, forcing emergency stops in traffic.
When: While driving at highway speeds; reported at 60 mph, 29 mph, and while cruising
Symptoms owners cite: Complete loss of propulsion without warning; Battery gauge shows 6-10% charge remaining when power is lost; All electrical systems may become unresponsive; Vehicle must be towed; owner is stranded in roadway
Repairs/costs cited: Vehicle towed to Tesla service; no documented repairs provided in narratives
Recalls/TSBs owners mention: Tesla service claims battery was fully depleted despite display showing remaining charge; refused to investigate or replace battery under warranty despite vehicle being under manufacturer warranty
Rear Motor Inverter Failure
Power inverter controlling rear motor fails suddenly during driving, disabling rear motor and cutting off propulsion. Owner notes a recall exists for this defect on Model 3 vehicles.
When: While driving; warning appears on screen 10-15 seconds before complete failure
Symptoms owners cite: Warning message on screen directing driver to pull over; Vehicle loses all power and stops in middle of roadway; Rear motor disabled message displayed
Repairs/costs cited: Rear motor power inverter replaced at Tesla service center
Recalls/TSBs owners mention: Inverter replaced under warranty; owner notes Tesla recall for 127,785 Model 3s in China due to rear motor inverter defect
Complete Power Converter / Dual Motor System Failure
Power converter failure disables both front and rear drive motors, leaving vehicle immobile in traffic lane. Owner specifically purchased dual-motor model expecting redundancy but found single point of failure in power converter.
When: While driving on city road at night
Symptoms owners cite: Alert message on screen to slow down; Vehicle stops and places itself in park in right-hand lane; Both front and rear motors disabled; Unable to shift to neutral to move vehicle off road; Emergency flashers difficult to locate and disable when driver exits vehicle
Repairs/costs cited: Power converter was the failed component
HVAC Thermal Management System Failure (Pressure/Temperature Sensors)
HVAC system cooling and heating malfunction due to failing pressure and temperature sensors in the thermal management system that cools battery, inverters, and computing hardware. Tesla issued service bulletin SB-21-18-002 in 2021 but claimed software update would fix the issue without actually resolving it.
When: Random shutdowns; reported while supercharging and during winter conditions
Symptoms owners cite: HVAC cooling/heating system randomly shuts down; Warning message: cooling and heating may randomly be unavailable; Invalid sensor readings from pressure and temperature sensors; Loss of cabin heat in subzero temperatures; Potential thermal runaway risk during supercharging
Repairs/costs cited: Tesla advised sensor replacement at owner's expense despite acknowledging sensor defect
Recalls/TSBs owners mention: Tesla issued service bulletin SB-21-18-002 in 2021; claimed software update would resolve issue but did not; refusing to cover sensor replacement despite known defect
Onboard Computer / Display System Failure with Reboot
Vehicle computer system and CRT display malfunction including erroneous speed readings, unresponsive controls, and complete system reboot during operation. Speed indicator fails to respond to actual vehicle speed and displays incorrect speeds.
When: While driving on highway at speed
Symptoms owners cite: Speed indicator on display fails to respond to vehicle speed changes; Speed indicator displays erroneous speeds (displayed 34 mph while traveling 60 mph); Drive (D) and reverse (R) indicators on display do not show current gear selection; Screen goes completely black with faint Tesla logo appearing; Vehicle computer reboots during operation; System returns to normal operation after reboot
Adaptive Cruise Control (Autopilot) - Phantom Braking and Unintended Engagement
Adaptive cruise control system applies unexpected braking at highway speeds in response to non-existent obstacles. System frequently misidentifies highway signs or road features as stopped vehicles and applies sudden braking. System has disengaged and reengaged unexpectedly.
When: Occurs repeatedly during use; reported >10 times on same vehicle; happens on highways and city roads
Symptoms owners cite: System applies light to heavy braking without driver input or obstacle present; Braking occurs at highway speeds in traffic; System mistakes highway signs for stopped vehicles; Braking is unpredictable and unnecessary; System disengages unexpectedly; Creates risk to following traffic due to sudden deceleration
Recalls/TSBs owners mention: Tesla has been unable to remedy this problem
Unintended Acceleration
Vehicle accelerates on its own without driver input, causing loss of control and collision. Two separate incidents reported—one at near-stationary speed resulting in $20,000 damage, another at 29 mph resulting in tree collision. No warning lights precede either event.
When: While vehicle is stationary or moving slowly; 80,340 miles on one vehicle
Symptoms owners cite: Vehicle accelerates without throttle input; No warning lights illuminated before acceleration; Driver loses control of vehicle; Vehicle leaves roadway at high speed; Results in collisions with obstacles
Repairs/costs cited: One vehicle remained at residence and was not repaired; other vehicle damage estimated at $20,000 by insurance
Loss of Power / Drivetrain Cutout While Driving
Vehicle loses power or propulsion while driving at highway speed. Pressing accelerator pedal produces no response. Problem resolves itself when driver applies brake. Reported as recurring issue on same vehicle (3rd occurrence).
When: While driving on highway; recurring issue with multiple tow incidents
Symptoms owners cite: Sudden loss of power while driving at highway speed; Accelerator pedal becomes unresponsive; Power restored when driver applies brake; Issue appears to be intermittent and recurring
Repairs/costs cited: Vehicle towed to shop on three separate occasions; no specific repair details provided
Rear Motor Lockup / Sudden Shutdown While Shifting
Drivetrain locks up when shifting into reverse while parked, causing vehicle to lurch. System displays warning messages indicating rear motor disabled and vehicle shutting down. Owner expresses concern that if this occurred while driving, it could cause sudden stop and accident.
When: While parked, during reverse selection
Symptoms owners cite: Vehicle lurches when selecting reverse; Warning message: Rear motor disabled - safe to drive; Warning message: Vehicle shutting down - PULL OVER SAFELY; Drivetrain becomes locked up; Vehicle requires towing
Repairs/costs cited: Vehicle was towed away
Cruise Control Scroll Wheel Unresponsiveness
Right scroll wheel on steering column fails to respond to adjustment inputs while using adaptive cruise control. Owner cannot adjust set speed in response to construction zone speed limit change.
When: While driving at 65 mph in construction zone
Symptoms owners cite: Right scroll wheel does not respond to speed adjustment input; Cannot reduce cruise control speed from 65 to 55 mph
Regenerative Braking System Failure
Regenerative braking function fails to engage when driver applies brake pedal during cruise control operation. System does not provide expected braking response.
When: While driving at 60 mph with cruise control enabled approaching highway exit
Symptoms owners cite: Regenerative braking does not apply when brake pedal is pressed; Feels as though cruise control did not turn off; Physical braking did eventually stop vehicle successfully
Synthesized from 15 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had powertrain trouble with your 2021 Tesla Model 3?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2021 Tesla Model 3?
It's a meaningful issue. 15 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $2,500.
At what mileage does the powertrain typically fail?
Based on the 15 complaints filed, powertrain issues most often appear around 80,340 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Tesla/Model 3.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.