IsItAGoodCar
Reliability Guide

Common Problems with the
2021 Ford Mustang Mach-E

Launch year: UK deliveries began in 2021 with rear- or all-wheel drive, 68kWh Standard Range and 88kWh Extended Range usable packs, and a cabin built around a 15.5-inch SYNC 4A screen.

What changed for 2021

  • •Standard Range 75.7kWh (68kWh usable) and Extended Range 98.8kWh (88kWh usable) batteries
  • •RWD and dual-motor AWD from 269bhp to 346bhp, with the 480bhp GT joining later in 2021
  • •15.5-inch portrait touchscreen, 10.2-inch driver display and Phone As A Key
  • •First Edition launch trim in Grabber Blue, Carbonised Grey or Rapid Red

Common MOT watch-outs

  • !Uneven tyre wear and kerbed 19 and 20-inch alloys on a 2.2-tonne SUV
  • !Pitted brake discs where regenerative braking means the friction brakes are seldom used
  • !Worn front lower arm bushes and noisy dampers reported from around 30,000 miles
4
Known Issues
1
Serious
1
Moderate
2
Minor

All Known Issues

High Voltage Battery Junction Box (HVBJB) Failure

SeriousElectrics & Electronics

The main high-voltage contactors can overheat and weld shut or stick open, especially after rapid acceleration or DC fast charging. This results in a sudden loss of motive power.

Est. Repair Cost: £0 (Under Warranty/Recall)
Warning Signs:

"Stop Safely Now" message, Total loss of drive, Car refuses to charge

What to Inspect:
  • Verify with a Ford dealer if the HVBJB recall campaign has been completed for that specific VIN
Verified by IsItAGoodCar Research Team

Charging System Faults and 12V Battery Issues

ModerateElectrics & Electronics

The Mach-E relies on a small 12V auxiliary battery to power the charging contactors and control modules. If the 12V drops below 11.5V, charging will not start even though the main battery is full. Charge port actuator failures and onboard charger faults also cause charging to fail or stop mid-session.

Est. Repair Cost: £60-£500
Warning Signs:

Unable to charge or Charging fault message, Charge port door will not open, Charging stops mid-session, 12V battery low warning

What to Inspect:
  • Check 12V battery health and age
  • Test charge port door operation
  • Verify FordPass app connectivity
  • Try charging at a public and home charger
Verified by IsItAGoodCar Research Team

Software and SYNC 4A Infotainment Glitches

MinorElectrics & Electronics

The 15.5-inch touchscreen may freeze, go blank or lag badly, temporarily knocking out climate control and drive-mode controls. Apple CarPlay audio can cut out, rearview cameras can freeze and driver-assistance features can temporarily go offline.

Est. Repair Cost: £0-£400
Warning Signs:

Frozen or black central screen, Apple CarPlay audio cutting out, Rearview camera freezing, Driver-assistance messages disappearing

What to Inspect:
  • Run navigation, audio and phone pairing during the drive
  • Check current software version
  • Ask if OTA updates have been applied successfully
Verified by IsItAGoodCar Research Team

Build Quality and Wind Noise

MinorBodywork & Rust

Early Mach-E builds drew criticism for inconsistent panel gaps, wind noise around mirrors and A-pillars at highway speeds, paint imperfections and interior creaks and rattles. By 2024 Ford factory processes had improved but these issues still show up in the used pool.

Est. Repair Cost: £0-£500
Warning Signs:

Wind noise around mirrors or A-pillars at speed, Creaky dashboard or buzzing door panels, Uneven panel gaps or paint imperfections, Hatch-area rattles over rough roads

What to Inspect:
  • Inspect panel gaps and paint condition
  • Listen for wind noise on a motorway test drive
  • Check for signs of windshield reinstallation
Verified by IsItAGoodCar Research Team

Buying Tips for 2021 Ford Mustang Mach-E

  • Check the 12V auxiliary battery age and voltage; a weak one prevents charging and start-up
  • Ask a Ford dealer to confirm the high-voltage battery junction box recall and all software campaigns are closed for the VIN
  • Read the battery state of health from the service menu and compare it with the mileage
2022
Check a 2021 Ford Mustang Mach-E by Registration