It has several error messages including "Stop safely now". This seems to be the same issue as recall 23S56 (TSB 22-2178). The vehicle is not drivable as it will not start or go into gear. Seems to be known issue with the HVBJB.
2021 Ford Mustang Mach-E powertrain problems
severe Owners of the 2021 Ford Mustang Mach-E have filed 48 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
48
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2021 Mustang Mach-E (this page) | 48 |
| 2022 Mustang Mach-E | 27 |
1crash
2injuries
What stands out
Owners have filed 48 powertrain complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
The failure pattern owners describe
The 2021 Mustang Mach-E powertrain exhibits a pattern of High-Voltage Battery Junction Box (HVBJB) failures where internal contactors degrade under normal driving and charging, leading to sudden loss of propulsion, power steering, and power brakes. Owners report the vehicle displays warnings like "Stop Safely Now" before going completely dead—sometimes on the highway at speed—and cannot shift out of Park without external power. The damage occurs invisibly inside the HVBJB; by the time warning lights appear, the failure is already underway. Ford's recall fixes have been software-only patches that limit power when contactors overheat, not removal of the faulty parts themselves. Even after dealers replace the HVBJB with allegedly redesigned units, owners report identical failures recurring within weeks or months. A second major issue is uncontrolled acceleration or deceleration independent of pedal input, which has caused at least one serious crash. Brake pedal bounce, shift-system faults locking the vehicle in Park or Accessory mode, and complete 12-volt electrical system drain during operation round out the complaints. Dealerships frequently refuse to perform warranty work without stored diagnostic codes, leaving owners stranded and forcing them to drive the vehicle until catastrophic failure occurs—precisely the scenario that creates highway safety hazards.
Same Ford Mustang Mach-E powertrain reports on nearby years: 2022
Failure modes owners describe
High-Voltage Battery Junction Box (HVBJB) Contactor Failure
Internal contactors in the HVBJB become damaged under normal driving and charging conditions. Damage is not visible externally until warning lights appear after failure has occurred. Contactors can exceed resistance thresholds (owners cite .5 ohms limit per OSP patch), leading to loss of propulsion, loss of 12-volt charging, and inability to move the vehicle or shift gears.
When: Typically under 50k miles; can occur within 2 months of ownership; some failures repeat after dealership repairs
Symptoms owners cite: High-voltage battery warning light; Powertrain malfunction warning; Yellow turtle warning light (reduced power mode); Wrench and car-with-exclamation warning lights; 'Stop Safely Now' alert on dashboard; Complete loss of motive power while driving; Vehicle stuck in Park or Accessory mode; unable to shift to Drive/Neutral; Loss of power steering and power brakes; Sudden vehicle deceleration or inability to accelerate; 12-volt battery fails to charge properly; Vehicle refusal to start despite high battery charge
Codes mentioned: P0AA1, P0AA2, P0ADA
Repairs/costs cited: Dealers typically replace the entire HVBJB assembly. Ford has issued a 'more robust' or 'redesigned' HVBJB with different internal components; however, owners report failures recurring even after replacement with the supposedly upgraded unit. Some dealers report only part-number updates (sticker/label changes) with no internal component changes. Replacement takes several weeks due to parts availability and technician training requirements.
Recalls/TSBs owners mention: Ford recall 22S41 (software-only OSP update to limit power when contactors exceed .5 ohms resistance) and recall 23S56 (electronic parking brake harness connector replacement and battery charge control module reprogramming). Recall 22V333000 (Vehicle Speed Control, Powertrain). TSB 22-2178. TSB 26-2005 documents a fault capable of draining the 12-volt electrical system during vehicle operation. Owners cite that recalls are software-only or partial hardware measures and do not mandate replacement of the known-to-fail contactors. Recall 22S41 initially listed for higher-end models only; VINs not listed on recall bulletins may exhibit identical symptoms but dealers refuse service without stored diagnostic codes.
Uncontrolled Acceleration or Deceleration (Independent of Pedal Input)
Vehicle accelerates or decelerates without driver foot pressure on the pedal. Occurs while in Drive, at traffic signals, during gear shifts, or in the middle of normal driving. One case occurred while reversing and shifting to Drive; another while the driver had foot on the brake. Cruise control and One Pedal Drive systems also implicated.
When: Can occur at low speeds (3–30 mph) or highway speeds (55+ mph); some owners report 20+ occurrences over weeks before recall update; one failure at 18,000 miles resulted in crash
Symptoms owners cite: Sudden high-speed acceleration without pedal input; Sudden deceleration without pedal input; Lurching or jerking motion after shift; Loss of acceleration response when pedal is depressed, followed by burst of speed; Cruise control malfunction (erratic acceleration/deceleration); One Pedal Drive mode causing unexpected behavior
Codes mentioned: Associated with recalls 22V333000
Repairs/costs cited: Owners report dealership software updates; recall 22V333000 was supposed to address vehicle speed control but multiple owners state the issue persists post-update. One crash resulted in vehicle being totaled; occupants sustained fractured rib and multiple injuries.
Recalls/TSBs owners mention: Recall 22V333000 (Vehicle Speed Control, Powertrain) issued 5/30/2022. However, owners report continued failures after software update, suggesting the fix is incomplete.
Loss of 12-Volt Electrical System During Operation
The 12-volt battery or charging system fails while the vehicle is in motion, causing complete loss of propulsion, power steering, power brakes, and accessory functions (hazard lights, wipers, door locks). Vehicle becomes immobilized and cannot be shifted to Neutral without external 12-volt jump start.
When: While driving at highway speeds (45–65 mph); one case after 2 hours of coasting following loss of high-voltage power
Symptoms owners cite: Complete loss of propulsion while in motion; Loss of power steering; Loss of power brakes; Loss of hazard lights; Loss of door-lock function; Vehicle unable to enter Neutral without external 12-volt jump; Electrical system gradually shutting down; Battery warning light (12-volt icon) on dashboard
Codes mentioned: Associated with TSB 26-2005 (intermittent software condition draining 12-volt system)
Repairs/costs cited: Owners report tow trucks requiring 12-volt jump-start to move vehicle off highway. One owner had to wait 2 hours in 90-degree heat with no AC; another blocked traffic for 2 hours in rainy conditions. Dealers have replaced 12-volt batteries and reprogrammed modules, but root cause attributed to HVBJB failure preventing proper 12-volt charging during operation.
Recalls/TSBs owners mention: TSB 26-2005 documents the issue. Ford acknowledges that 12-volt power is required to shift vehicle into Neutral, creating a safety trap: the HVBJB failure prevents 12-volt charging, which prevents towing without external power.
Brake System Failure and Loss of Braking Control
Brake pedal bouncing, loss of braking pressure, sudden independent braking while driving or in reverse, and inability to operate brakes when power is lost. One case involved brake pedal bouncing up and down while driving in rain.
When: At low speed (3–25 mph); one case at 20–25 mph in rain at night
Symptoms owners cite: Brake pedal bouncing up and down; Loss of braking power when high-voltage system fails; Sudden independent braking in reverse; Stiff steering (indicating loss of power assist); Hazard lights inoperable during braking events
Codes mentioned: Associated with recalls 22V333000
Repairs/costs cited: No repairs documented in complaints; one vehicle was towed and not diagnosed.
Recalls/TSBs owners mention: Recall 22V333000 was to address vehicle speed control; unclear if braking issues were targeted.
Shift System Fault and Inability to Shift Gears
Vehicle displays 'Shift System Fault' or becomes stuck in Park/Accessory mode and will not shift into Drive, Neutral, or Reverse. Parking brake may also become locked. Issue is intermittent and can recur within hours or weeks after dealership repair.
When: Typically at low speeds or while stationary; recurrence noted within two weeks of prior repair
Symptoms owners cite: 'Shift System Fault' dashboard warning; Vehicle will not shift out of Park; Vehicle will not shift into Neutral (blocks towing); Vehicle stuck in 'Power Accessory Active' mode; Parking brake cannot be released; Vehicle becomes immobilized for 30+ minutes before recovering intermittently
Repairs/costs cited: Dealers perform software updates and test drives; no permanent fix documented. Two complaints report the same fault recurring after dealership visit within 10–14 days. One owner had to wait for tow truck requiring wheel lift and dolly due to shift system lock.
Recalls/TSBs owners mention: Software updates; no recall or TSB specifically cited for shift faults, though likely related to HVBJB/BECM issues.
Front Motor Failure Due to Oil Leak
Oil leak from the front motor assembly causes internal damage and motor failure. Owner received powertrain malfunction warning and grinding noise; dealer diagnosed front motor failure and ordered replacement.
When: At 45,000 miles
Symptoms owners cite: Grinding noise from powertrain; Powertrain malfunction warning; Reduced power mode; Hill start assist warning unavailable; Pre-collision assist not available
Repairs/costs cited: Front motor was replaced; original part number was superseded. Owner concerned about power loss while driving to dealer.
Recalls/TSBs owners mention: No recall or TSB cited; appears to be warranty repair.
Intermittent Software Fault Causing Sudden Loss of Propulsion
Complete loss of propulsion without warning, reduced-power mode, or dashboard alert prior to shutdown. Post-failure diagnosis identified an intermittent software condition documented in TSB 26-2005, which drains the 12-volt electrical system during operation. Root cause not the 12-volt battery itself but the software fault preventing proper 12-volt charging.
When: While driving under normal conditions
Symptoms owners cite: Sudden complete loss of propulsion; No prior warning or alert; No reduced-power mode preceding failure; No dashboard or mobile app notification before shutdown; No warning after shutdown; 12-volt electrical system drain during operation
Codes mentioned: TSB 26-2005 (12-volt system drain)
Repairs/costs cited: No repair details provided; TSB 26-2005 documents the fault but owners indicate the issue is not permanently resolved.
Recalls/TSBs owners mention: TSB 26-2005 acknowledges the condition; root cause is intermittent software, not 12-volt battery failure.
Synthesized from 48 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Had powertrain trouble with your 2021 Ford Mustang Mach-E?
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 Ford Mustang Mach-E?
It's a meaningful issue. 48 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 48 complaints filed, powertrain issues most often appear around 20,400 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/Ford/Mustang Mach-E.
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.