One problem related to computer failure has been reported for the 2003 Volkswagen Passat. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Volkswagen Passat based on all problems reported for the 2003 Passat.
Design defect results in failure of computer due to water flooding. Computer failure results in disabling of vehicle and expensive repairs. This condition caused by parking the car where leaves occasionally fall onto it. Reason: windshield drains into compartment containing the battery, which has a drain hole located under the battery, requiring removal of battery to properly clean. Drain gets clogged due to leaves, resulting in battery compartment filling with water. When this happens, water enters passenger compartment foot well. I took my car to vw dealer with this condition and they told me the computer could get flooded/ruined and this would not be covered under warranty due to "external influence". They agreed to clean the drain free of charge, but were unable and unwilling to provide me with a service advisory that the drain must be cleared to prevent computer damage. I contacted vw of America and they acknowledge the problem over the phone but refused to provide any written statement of the existence of the problem and refused to provide a written, permanent remedy for this problem, or to modify the car so this would not happen.