IsItAGoodCar
Reliability Guide

Common Problems with the
2015 Audi A8 Mk3 (D4)

By 2015 the D4 had received updates to trim and technology. The 3.0 TDI timing chain issue is less severe on later cars but still warrants checking. This is generally the safest used D4 buy if properly maintained.

What changed for 2015

  • •Updated MMI with improved graphics
  • •Revised engine calibration for lower emissions
  • •Enhanced driver-assistance options
  • •Updated interior trim materials

Common MOT watch-outs

  • !Air suspension leaks at 80k–140k miles
  • !Cooling system leaks from valley area
  • !Electrical module faults as mileage increases
4
Known Issues
2
Serious
2
Moderate
0
Minor

All Known Issues

Air Suspension Failure

SeriousSuspension & Chassis

Air struts leak and the compressor burns out trying to compensate. This is a common and expensive reality of aging luxury cars.

Est. Repair Cost: £1,000–£3,000
Warning Signs:

Car sits low on one corner overnight, Air suspension fault warning, Loud compressor noise from the front bumper area

What to Inspect:
  • Check the car sits level before the engine is started
  • Cycle the ride height through its settings
Verified by IsItAGoodCar Research TeamUpdated

4.0 TFSI Turbo Strainer Blockage

SeriousEngine

A tiny oil strainer screen feeding the twin turbos can block with carbon, starving the turbos of oil and causing rapid, catastrophic failure.

Est. Repair Cost: £3,000–£5,000
Warning Signs:

Siren noise from turbos, Loss of power, EPC light on

What to Inspect:
  • Ask if the oil strainer has been replaced or removed (a common preventative fix)
  • Check for extremely regular high-quality oil changes
Verified by IsItAGoodCar Research TeamUpdated
Official Recalls & Reference Documents:

Electrical Module and Sensor Failures

ModerateElectrics & Electronics

The complex electronics produce various module failures including air suspension control units, comfort modules, and sensor faults as the car ages.

Est. Repair Cost: £200–£1,500
Warning Signs:

Multiple dashboard warnings, Central locking faults, Infotainment glitches, Battery drain

What to Inspect:
  • Run full diagnostic scan with VCDS
  • Test all comfort and convenience functions
  • Check for parasitic battery drain
Verified by IsItAGoodCar Research Team

Cooling System Leaks

ModerateCooling System

The coolant regulating valve, water pump, and various plastic hoses can leak, causing gradual coolant loss and potential overheating.

Est. Repair Cost: £350–£1,000
Warning Signs:

Low coolant warning, Pink residue around engine, Sweet smell after shutdown

What to Inspect:
  • Check coolant level from cold
  • Inspect for staining around the water pump and valley area
  • Look for coolant residue on the belly tray
Verified by IsItAGoodCar Research Team

Buying Tips for 2015 Audi A8 Mk3 (D4)

  • Later cars with updated timing chain tensioners are preferable
  • Check all MMI and comfort functions thoroughly
  • Budget for air suspension attention on any high-mileage example
2012–20142016–2017
Check a 2015 Audi A8 Mk3 (D4) by Registration