We've identified 6 known issues that can affect the 1999–2000 Audi A6 Mk2 (C5). 2 of these are serious faults that could be expensive to repair.
Leaves and debris block the drains, leading to water entering the cabin and damaging the CCM.
Wet front carpets, Electrical behaving strangely
Early sliding-rocker versions can suffer cam and rocker wear. Later roller-rocker engines differ, so identify the engine code and valve gear before judging the risk.
Uneven running, Progressive loss of power or top-end noise
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.
Clunking over bumps, Imprecise steering, Uneven tyre wear
The dot-matrix LCD in the instrument cluster loses pixels column by column, making the trip computer, odometer and warnings unreadable.
Partial or blank display, Hard to read fuel level or temperature, Trip computer unreadable
The Bosch 5.3/5.7 ABS control unit develops internal solder faults, triggering ABS and brake warning lights and sometimes causing speedometer dropouts.
ABS and brake warning lights, Speedometer dropping to zero, Three beeps on startup
Wires in the rubber boot between the body and driver door fatigue and snap over time, causing central locking, window and mirror failures.
Door window stops working, Central locking intermittent, Mirror adjustment fails