Due to the complexity of the systems used in modern vehicles, troubleshooting can be an arduous process. This applies to both the electronic and the mechanical parts of the vehicle. However, mistakes made by users when operating Passive Entry / Go systems can also lead to the impression that the systems are not working properly. As such, it is important to follow the operating instructions and the manufacturer's specifications precisely.
Due to the design of the system and the CAN bus networking of the control units, troubleshooting is not possible without a suitable diagnostic unit and manufacturer-specific documentation such as repair instructions, circuit diagrams, and functional descriptions. For instance, in our example vehicle, the Passat B6, three separate control units and the ignition lock all need to be enabled in order to unlock the electronic steering lock.
This type of redundancy is built into the system in order to meet the stringent security requirements. It is also becoming more complicated to replace defective control units. In the Passat, the control units (e.g. comfort control unit, engine control unit) that are part of the immobiliser system can now only be taught online. This means that an authorised garage always needs to be contacted, even after the diagnostics have been run successfully.