The Volkswagen Passat is a large family car that the VW group classifies as resting between the Golf and the Phaeton in its market category. The original design results from VW’s desire to begin manufacturing front wheel drive cars with water-cooled engines, and the release of the 1st generation Passat marks a shift in VW’s manufacturing trends to fulfill these principles. The Passat B5, produced from 1996 to 2005, remains one of the most popular Passat generations, and featured an improvement in aerodynamic structure. A recall has been issued for this particular model due to malfunctioning engine coils.
Engine coils (also called ignition coils) transform the relatively low voltage emanating from the battery into the thousands of volts that the spark plug needs in order to make the spark that ignites the fuel. Problems originating in the coil manifest themselves in the car’s idle, which will become rough due to dropped sparks and subsequent cylinder misfiring. Because a dropped spark results in less fuel being ignited (and thus more fuel needed to run the car), engine coil trouble also increases the B5’s fuel consumption. Usually, a check engine light will signal that there is a problem.
The cause of your bad engine coil most likely stems from a crack in the coil, allowing moisture to enter and short out the spark (this is why the misfiring problems often increase in inclement weather or early in the morning, when dew settles over the pack). If not taken care of, the excess fuel can destroy the catalytic converter and cause premature wear on the crankcase.
As soon as the check engine light comes on, your B5 is trying to tell you something. Listen to your car and take it to a local German import maintenance garage. The longer you wait, the more damage the broken engine coil will cause.
Search for a local, independent Volkswagen repair shop with Volkswagen mechanics that have dealer-level expertise at a fraction of the expense.