2004 Audi A4 Problems

RepairPal has identified the most common problems with the 2004 Audi A4 as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

Refine by vehicle
×
Choose your vehicle
18
Known Problems

An ignition coil or spark plug may fail unexpectedly resulting in an engine misfire and possible illumination of the Check Engine Light. Vehicles equipped with spark plug wires may also develop a misfire caused by a failed spark plug wire.

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

Clogged drains can allow rainwater to accumulate in the plenum tray (at the base of the windshield). The water may leak into the vehicle's interior, brake booster, or electrical components, which can lead to major problems. Our technicians recommend keeping the tray clear of leaves, pine needles, and other debris.

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

The Cabriolet convertible top mechanism can fail due to hydraulic fluid leaks. The fluid reservoir is a common failure.

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

The water pump may fail resulting in engine overheating and possible timing belt damage. Overheating and/or timing belt failure can result in very expensive engine repairs. As a precaution, it is recommended to inspect the timing belt and water pump at regular intervals.

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

Vacuum leaks, oxygen sensor failure, and catalytic converter efficiency faults can 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.

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.
To avoid sludge accumulation inside the engine, our technicians recommend using the proper synthetic oil with the appropriate oil filter.

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.