Your Volkswagen B5 Passat, like other modern vehicles, contains an on-board computer that manages fuel, emissions, the drivetrain and other elements of your car. When your Volkswagen B5 Passat is not running properly, the computer will store a trouble code related to the problem. The computer then displays the "Check Engine" light, informing you of the problem. After the problem is taken care of, sometimes the "Check Engine" light will fail to go out, and your car's computer will have to be reset.
Turn off your Volkswagen B5 Passat.
Raise your Volkswagen B5 Passat's hood and locate the car's battery.
Wipe the battery's cables and terminals with a soft cloth to remove any corrosion and dirt. Wear latex gloves to keep your hands clean.
Use a wrench or socket set to disconnect both the positive and negative cables from the battery terminals.
Wait 15 seconds, then touch the ends of the positive and negative cables together for 10 seconds.
Reconnect the positive cable to the battery first then the negative cable.
Leave your driver's side car door open. Place the Volkswagen B5 Passat key in the ignition. Your driver's side car door needs to be open---the computer cannot be reset with the door closed or with the car running.
Turn the ignition to the "On" position but do not start the car.
Leave the key in the "On" position for 30 seconds.
Turn on your Volkswagen B5 Passat---the computer is now reset.
If the problem that caused the "Check Engine" to come on in your B5 Passat is not corrected, the computer may still display the light, after a few minutes, when you begin driving the car.