IsItAGoodCar

Common Problems with the
2018–2021 Audi A8 Mk4 (D5)

We've identified 4 known issues that can affect the 2018–2021 Audi A8 Mk4 (D5). 2 of these are serious faults that could be expensive to repair.

4
Known Issues
2
Serious
1
Moderate
1
Minor

The 2018–2021 period has 3 more issues than the Audi A8 Mk4 (D5) average across all year periods.

All Known Issues

48V Belt-Starter Generator (BSG) Failure

SeriousElectrics & Electronics

The Continental BSG power transistors overheat and fail, causing the 48V system to shut down and eventually leaving the car stranded.

Most affected: 50 TDI, 55 TFSI

Estimated cost: £0 (recall) – £2,500Affects: 2018–2021Often appears around: 20k-60k miles

Typical symptoms

  • •Multiple electrical system warnings
  • •Start-stop inactive
  • •Car immobilised after standing

What to inspect before you buy

  • ✓Verify service campaign 27BQ has been completed via VIN
  • ✓Check for electrical system warnings on startup
  • ✓Ask for BSG replacement invoice

Air Suspension Strut Leaks

SeriousSuspension & Chassis

The standard adaptive air suspension develops leaks over time, causing uneven ride height and expensive compressor replacement.

Most affected: All models

Estimated cost: £800–£3,000Affects: 2017–2024Often appears around: 50k-100k miles

Typical symptoms

  • •Car sitting low on one corner
  • •Compressor running constantly
  • •Level-control warning

What to inspect before you buy

  • ✓Check ride height before engine start
  • ✓Cycle through height settings
  • ✓Listen for compressor strain

Dual-Touchscreen MMI Freezes

ModerateElectrics & Electronics

Both the upper and lower MMI screens can freeze, go black, or reboot, affecting navigation, climate and seat controls.

Most affected: All models

Estimated cost: £0–£2,500Affects: 2017–2024Often appears around: Age-related

Typical symptoms

  • •Upper screen going black
  • •Lower climate screen unresponsive
  • •Spontaneous system reboots

What to inspect before you buy

  • ✓Test both screens extensively
  • ✓Try a 15-second power button reset
  • ✓Check for pending software updates

Software and Vehicle Management Glitches

MinorElectrics & Electronics

The extensive software architecture can produce phantom warnings, driver-assistance calibration issues, and infotainment bugs.

Most affected: All models

Estimated cost: £0–£500Affects: 2017–2024Often appears around: Age-related

Typical symptoms

  • •Phantom dashboard warnings
  • •Adaptive cruise calibration issues
  • •Infotainment glitches

What to inspect before you buy

  • ✓Check for all pending software updates
  • ✓Test all driver-assistance systems
  • ✓Verify no persistent fault codes

Buying Tips for the 2018 Audi A8 Mk4 (D5)

  • ✓Verify the 48V belt-starter-generator service campaign has been completed — this is critical on 2018-2021 cars
  • ✓Check both MMI touchscreens for lag, freezing or dead spots
  • ✓Air suspension must sit level and raise/lower without excessive compressor noise
  • ✓Ask for evidence of regular oil changes on the 3.0 TFSI to protect the water pump
2017 Audi A8 Mk4 (D5)2022–2024 Audi A8 Mk4 (D5)

Browse 2018–2021 Audi A8 Mk4 (D5) in our Directory

View MOT history, registration data, and reliability scores for 2018–2021 Audi A8 Mk4 (D5) vehicles.

View 2018–2021 Directory

Other Audi A8 Mk4 (D5) Year Periods

20172018–20212022–2024

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