On these engines the oil pump is driven by its own small toothed belt, and that belt runs in the hot engine oil. This is not the large timing belt that drives the camshafts, it is a separate belt in the lower part of the engine. In the oil the rubber hardens over time, its surface starts to crumble, and the loose particles block the suction side of the oil pump, so the oil pressure drops. If the belt snaps, the oil pump stops at once and the engine is left without lubrication within seconds. The rubber crumbs can also ruin the turbocharger and the camshaft adjuster, because they are lubricated from the same oil circuit. The maker specifies no replacement interval for this belt, so most cars still carry the one fitted at the factory, and the failures are reported above 150,000 km. Oil outside the specification and a stretched oil change speed the process up, because this belt ages in the oil. Replacing the belt itself costs between 200 and 600 euro, as long as the engine has not run without oil pressure.

The wiring harness running under the driver's seat kinks and breaks from the seat being adjusted. The sign is the airbag light staying on on the dash. With the airbag light on the system will not work in a crash, and it fails the roadworthiness test too. The part is cheap, the fault finding is the expensive bit, and many sellers mention it as "just a light".

The EGR valve and its cooler block up with soot and oily deposits; the particulate filter cannot regenerate on short urban trips. The signs are reduced power, a warning light, and frequent regeneration. The software update after the diesel emissions affair made the EGR operate more often, which accelerated the phenomenon: the maker gave goodwill repairs in several cases.

The solenoids of the mechatronics unit wear out: slow or harsh shifting, then limp mode. A characteristic sign is the partial or complete loss of reverse. Wear of the clutch pack or the wrong spring force causes jerking and slipping. Because of the wet design it fails less often and at higher mileage than the dry DQ200, but when it does fail, it is expensive.

On this engine the water pump is driven by the timing belt, and the plastic impeller of the pump, along with its electronically controlled shut-off ring, is the weak point: the ring sticks, and the impeller separates from the shaft or disintegrates. The first sign is slowly disappearing coolant and heating that stays cold for a long time. The real risk is not the price of the pump: the leaking water washes the grease off the timing belt rollers, and from then on the belt is what fails. If the timing belt snaps, the engine is badly damaged inside. That is why the two are always replaced together.

The Aisin automatic of the transverse engine VAG models locks the torque converter across a wide slip range, which gains on fuel consumption but loses on the life of the friction lining. The sign of wear is a vibration or "buzzing" felt at lock-up, and the lock-up cycling on and off.

The door seal ages, and the water runs into the front footwell. It stays in the foam under the carpet, so for a long time only the misting windows and the musty smell show it. The comfort control unit and several connectors run in the footwell: if they corrode, the fault is electrical from then on.

A thin wall of the mechatronics valve body can crack, which causes a loss of pressure. The typical signs: jerking and harsh shifting from 1st to 2nd at low speed, a flashing PRNDS display, then a gear engagement fault, intermittently at first.

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 rear calipers seize: the pad does not release, the disc overheats and turns blue, the car pulls to one side under braking, and the fuel consumption rises unnoticed. On salted winter roads it develops faster. The symptom is easy to mistake for simple pad wear, but a seized caliper takes the disc with it, and often the wheel bearing too.

The dash shows "Error: Workshop! Only leave vehicle in position P" with an audible warning. The message appears in whatever language the car is set to, for example "Fehler: Werkstatt! Fahrzeug nur in Stellung P verlassen" in German.