IsItAGoodCar

Common Problems with the
1999–2004 Audi A6 Mk2 (C5)

We've identified 5 known issues that can affect the 1999–2004 Audi A6 Mk2 (C5). 1 of these are serious faults that could be expensive to repair.

5
Known Issues
1
Serious
4
Moderate
0
Minor

The 1999–2004 period has 2 more issues than the Audi A6 Mk2 (C5) average across all year periods.

All Known Issues

Blocked Plenum Drains

SeriousBodywork & Rust

Leaves and debris block the drains, leading to water entering the cabin and damaging the CCM.

Most affected: All models

Estimated cost: £100–£800Affects: 1997–2004Often appears around: Age-related

Typical symptoms

  • •Wet front carpets
  • •Electrical behaving strangely

What to inspect before you buy

  • ✓Feel the carpet in the front footwells

Front Multi-Link Suspension Wear

ModerateSuspension & Chassis

The C5 uses a sophisticated aluminium multi-link front suspension with eight control arms per side. Bushings harden and ball joints develop play, causing clunks and vague steering.

Most affected: All models

Estimated cost: £350–£900Affects: 1997–2004Often appears around: 80,000–120,000 miles

Typical symptoms

  • •Clunking over bumps
  • •Imprecise steering
  • •Uneven tyre wear

What to inspect before you buy

  • ✓Listen for clunks over potholes
  • ✓Inspect bushes and ball joints visually
  • ✓Check for multiple suspension advisories on MOT

Instrument Cluster Pixel Failure

ModerateElectrics & Electronics

The dot-matrix LCD in the instrument cluster loses pixels column by column, making the trip computer, odometer and warnings unreadable.

Most affected: All models

Estimated cost: £100–£400Affects: 1999–2004Often appears around: Age-related (typically after 80k miles)

Typical symptoms

  • •Partial or blank display
  • •Hard to read fuel level or temperature
  • •Trip computer unreadable

What to inspect before you buy

  • ✓Check all displays during startup
  • ✓Look for faded or missing pixel columns
  • ✓Ask if cluster has been repaired or replaced

ABS Module Failure

ModerateElectrics & Electronics

The Bosch 5.3/5.7 ABS control unit develops internal solder faults, triggering ABS and brake warning lights and sometimes causing speedometer dropouts.

Most affected: All models

Estimated cost: £200–£500Affects: 1997–2004Often appears around: 80,000–150,000 miles

Typical symptoms

  • •ABS and brake warning lights
  • •Speedometer dropping to zero
  • •Three beeps on startup

What to inspect before you buy

  • ✓Check dashboard warning lights
  • ✓Scan for ABS fault codes
  • ✓Ask if module has been rebuilt or replaced

Driver Door Wiring Loom Breakage

ModerateElectrics & Electronics

Wires in the rubber boot between the body and driver door fatigue and snap over time, causing central locking, window and mirror failures.

Most affected: All models

Estimated cost: £100–£300Affects: 1997–2004Often appears around: 80,000–150,000 miles

Typical symptoms

  • •Door window stops working
  • •Central locking intermittent
  • •Mirror adjustment fails

What to inspect before you buy

  • ✓Inspect wiring in the door boot for broken strands
  • ✓Test all door electronics
  • ✓Check for previous repair work on loom

Buying Tips for the 1999 Audi A6 Mk2 (C5)

  • ✓Check the front carpets for dampness (blocked plenum drains)
  • ✓The multi-link front suspension is complex and expensive to refresh
  • ✓1.8T models need proof of regular oil changes
1997–1998 Audi A6 Mk2 (C5)

Browse 1999–2004 Audi A6 Mk2 (C5) in our Directory

View MOT history, registration data, and reliability scores for 1999–2004 Audi A6 Mk2 (C5) vehicles.

View 1999–2004 Directory

Other Audi A6 Mk2 (C5) Year Periods

1997–19981999–2004

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