2003 Audi A6 Quattro Problems

RepairPal has identified the most common problems with the 2003 Audi A6 Quattro as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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19
Known Problems

Popping sounds from the rear of the vehicle may be heard moments after starting the engine, or when slowing to a stop. This noise is from the leak detection pump filling the fuel tank with air, and releasing to retest the system when it finds a fault. The sequence of faults identifying this issue are as follows:

  • Succession of loud pops from rear of vehicle
  • Pops go away, and fuel economy decreases 
  • Check engine light illuminates
  • OBD trouble code P2404 and/or P0441 is stored
  • Engine will not start after refueling (must crank for over 30 seconds)
  • Vibration when slowing to a stop

The cause is a valve which is mounted on the front of the intake manifold, commonly called the N80 valve, or EVAP system purge valve. The valve is designed to open under specific circumstances, but a worn valve will remain open at all times, preventing the pressurization of the fuel tank. 

Correction of the issue is to replace the N80 valve with the latest revision. 

The thermostat may erratically stick open or closed. The can result in illumination of the Check Engine Light and/or engine overheating.

The anti-lock brake system (ABS) control module may fail causing the ABS light to illuminate. Failed modules should be replaced to restore ABS operation.

The digital display portion of the instrument cluster may fail. Our technicians tell us the entire instrument cluster will need to be replaced to correct this concern.

Erratic turn signal operation can be a result of a failing turn signal flasher relay which will require replacement.

Our technicians recommend having the constant velocity (CV) boots and CV joints inspected at each service. Servicing torn CV boots early can prevent the need to replace the CV half shaft or CV joint.

Engine oil leaks are common from the valve cover gaskets and camshaft chain tensioner gasket.

A problem with the torque converter can cause the Check Engine Light to illuminate.

Fuel quality must be maintained to avoid engine misfire problems; the misfires may cause the Check Engine Light to illuminate.

Premature wear in various multi-link suspension components can cause noises that are difficult to diagnose. Worn suspension parts can also cause uneven tire wear and create steering alignment problems.

Vacuum leaks, oxygen sensor failure, and catalytic converter efficiency faults can cause the Check Engine Light to illuminate.

A fluid leak may develop from the propeller shaft seal on the rear of the transmission. Our technicians tell us that replacing the seal will commonly correct this concern.

Oil leaks from the camshaft drive pulleys and variable valve timing hydraulics are common. If the variable valve timing hydraulics is leaking, the Check Engine Light may illuminate from inaccurate valve timing.