The balance shaft module drives the oil pump through a hexagonal shaft stub. That hex and its mating part gradually round off, until the shaft finally turns freely: the oil pump stops and the oil pressure is gone. The process gives no warning, and that is exactly what makes it dangerous. The failure typically happens at high revs, and the oil pressure light comes on only once the damage is already done. The factory hex is undersized, so it knocks against the wall of the bore, and the wear accelerates itself. The maker classed it as a "tolerance deviation" and, given the small number of cases against total production, did not recommend preventive repair; Audi alone ran a service action (13D7). The replacement is expensive: on the German market the module replacement is 1,300 to 1,700 euro, and an independent repair touching only the hex is around 650 euro. The reported cases cluster around the Passat B6, Sharan, Audi A4/A6, Superb and Alhambra, in model years between 2005 and 2009. This layout is not only on the pump-injector (PD) engines, it is on the common rail EA189 engines too: the same module, the same hex, the same wear. The failure is typically reported between 100,000 and 160,000 km. The first sign is a short flash of the oil pressure light, in a long bend or a few seconds after a cold start, and then quiet again. The versions without balance shafts (BKD, BMM, BMN, AZV) drive the oil pump differently and are not affected by this wear. If the light stays on or flashes, stop as soon as it is safe, switch the engine off, and do not restart it until the oil pressure has been measured.

The internal springs of the flywheel tire, and the two discs knock against each other. The signs are a rattling or knocking from the bellhousing at idle and when releasing the clutch pedal, and vibration through the floor. If the clutch slips without a burnt smell, that also points to the flywheel. It is worth replacing in time: a disintegrated flywheel can destroy the bellhousing too. At a clutch replacement the two go together anyway.

The springs, dampers and control arm bushes wear far earlier than average. In the roadworthiness test the suspension failure rate on this model is many times the average: the TUV statistics have shown this for years. Symptoms: knocking on uneven roads, less confident cornering, uneven tyre wear. A broken spring also occurs, typically on overloaded cars.

Waves and grooves appear on the surface of the brake discs under 30,000 km, accompanied by pulsing felt through the steering wheel and the brake pedal when braking. The phenomenon is not a question of driving style: it is traced back to faulty production batches. VW sometimes contributed to the cost as a goodwill gesture, but rejected many claims. A full brake overhaul is a substantial item.

The water channel around the roof is plastic and the support frame is steel; the two expand differently, and a stress crack forms where they meet. Add to that a rear drain squashed during assembly. The water gets onto the headlining, and from there into the cabin and the electronics. The repair is often not durable: the workshop seals it or cleans a drain, and months later it comes back.