A data exchange system for use in vehicle assembly includes a data exchange mechanism exchanging vehicle software and/or diagnostic information between vehicle processors and an external processor. In one aspect, the data exchange mechanism is a portable memory device, such as a USB flash disk, alternately connecting to USB ports of the external processor and the vehicle. Vehicle software is automatically loaded onto vehicle processors by an interface processor connected to a CAN controller, and the processors similarly write back diagnostic information. In another aspect, the data exchange mechanism is a wireless mechanism, such as an iCHIP, connecting the external processor and vehicle processors through a communications network and a CAN controller. Vehicle processors individually wirelessly request appropriate vehicle software and/or provide diagnostic information. The data exchange mechanism may be permanently integrated into the vehicle, or temporarily connected to the vehicle by an alternative connection mechanism, such as the ALDL.