One problem related to transmission solenoid has been reported for the 2003 Volkswagen New Beetle Convertible. The most recently reported issues are listed below.
Near-miss but no traffic collision due to unexpected jerkiness, loss of power transfer to drive wheels, with associated revving of engine of 2003 vw New Beetle Convertible with automatic transmission, while I tried entering traffic stream on a busy street. Symptoms were intermittent for 9 months; now present whenever vehicle warmed up after 3 miles driving; vehicle not used for past 9 mo. Volkwagen dealer advises "replace transmission". Valve body failure in 6-speed tiptronic (aisin-warner 09g) automatic transmission causes hard upshifts and downshifts and lapses in power transfer, resulting in unsafe situations when merging onto freeway or into heavy traffic, for example. The 6 electrically controlled valves and associated solenoids in this transmission gradually wear out, typically soon after the Volkswagen 5-year, 60000-mile powertrain warranty expires. The problem is traceable to defective design of the combination of aluminum valve bores, shift valves which cause wear in the bores, faulty solenoids, and shift programming which relies on frequent electrically activated movement of the valves to modulate and produce smooth shifts between gears. The consequence of continuing to drive the car can be complete transmission failure, which may occur unexpectedly and place the driver in a dangerous situation if unable to pull off the roadway, or if failure occurs while attempting to merge or execute normal driving manuevers. In my case, the transmission operates well for the first 3 miles, but not when warmed up. Volkswagen of America announced a warranty extension on the "valve body only" for the 09g model transmissions, for a specific 7 years from vehicle-in-service date or 100,000 miles, whichever occurs first. I will have the valve body replaced by an independent transmission shop, using genuine vw parts, as vwofa has declined to repair my transmission or replace it completely unless I am willing to pay for a new transmission. The used parts will be saved.