IsItAGoodCar
Reliability Guide

Common Problems with the
2021 Audi Q4 e-tron

Launch era: UK orders opened in March 2021 with the MEB-based Q4 40 e-tron (77kWh gross battery, single rear motor) and 50 e-tron quattro following, priced against the BMW iX1 and Ford Mustang Mach-E; build quality is solid but early cars carry the full first-generation software load, and the small-battery 35 e-tron arrived later still.

What changed for 2021

  • •First Audi EV built at Zwickau and the brand's volume electric SUV
  • •40 e-tron single-motor and 50 e-tron quattro variants; Sportback roofline followed in 2021/22
  • •Augmented-reality head-up display and 12.3-inch virtual cockpit were class-leading options

Common MOT watch-outs

  • !Brake disc corrosion from infrequent hydraulic brake use on low-mileage cars
  • !Tyre replacement cost on 20/21-inch EV-spec tyres worn by the car's weight
  • !12V battery ageing leaves cars unable to start charging sessions
4
Known Issues
1
Serious
2
Moderate
1
Minor

All Known Issues

12V Auxiliary Battery Drain from Telematics Control Unit

SeriousElectrics & Electronics

The 12V auxiliary battery can suffer parasitic drain when parked if the Emergency Call (eCall) or online telematics gateway fails to enter sleep mode, immobilising the vehicle.

Est. Repair Cost: £150–£400
Warning Signs:

Vehicle completely dead after standing 48+ hours, "Electrical system: fault! Safely stop vehicle" warning, Remote app fails to communicate

What to Inspect:
  • Test 12V battery state of health
  • Check for telematics control unit software updates
Verified by IsItAGoodCar Research TeamUpdated

MMI Infotainment Screen Freezes and App Connectivity Drops

ModerateElectrics & Electronics

Early cars should be checked for software-related connectivity and charging-function issues. Audi offered software 3.2 for vehicles built through model year 2022, adding improved charging and online functions; verify the applicable update with the dealer.

Warning Signs:

MMI screen black on startup, Audio volume stuck or silent, myAudi app unable to start cabin climate preconditioning

What to Inspect:
  • Test MMI, phone pairing, charging timers and myAudi connectivity
  • Ask Audi to confirm the software version and VIN-specific update history
Verified by IsItAGoodCar Research TeamUpdated

Rear Drum Brake Sticking and Actuator Corrosion

ModerateBrakes

The Q4 e-tron uses sealed rear drum brakes to minimize rolling resistance and particle emissions. Due to heavy regenerative braking, internal electromechanical handbrake actuators can stick after parking in wet weather.

Est. Repair Cost: £200–£450
Warning Signs:

Loud clunk or binding when pulling away after rain, Electronic parking brake warning light, Uneven braking feel

What to Inspect:
  • Check handbrake release behaviour from standstill
  • Inspect rear drum casings for corrosion
Verified by IsItAGoodCar Research TeamUpdated

Heat Pump Expansion Valve Clicking & Efficiency Degradation

MinorCooling System

On models optioned with the heat pump, internal expansion valves can stick or click loudly in winter temperatures, reducing cabin heating performance and range efficiency.

Est. Repair Cost: £0–£600
Warning Signs:

Clicking or buzzing noise from behind dashboard in cold weather, Cabin slow to warm up in winter, Reduced winter range

What to Inspect:
  • Test cabin heating at maximum temperature
  • Listen for clicking noises from HVAC unit under the bonnet
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2021 Audi Q4 e-tron

  • Ask for the charging curve to be demonstrated on a fast charger, not just a home wallbox
  • Cars built after mid-2024 received the larger-capacity cell update - worth hunting for
  • Check the frunk and boot linings for dealer demo wear on off-lease examples
2022–2023
Check a 2021 Audi Q4 e-tron by Registration