How do I determine which OBD II protocol to use on a particular vehicle?
OBD II specifies 5 different electrical protocols which can be used to access OBD II information. Automotive manufacturers are required to implement one of the mandated OBD II protocols. CAN is becoming the mandated OBD II protocol for all new vehicles. In the near future all vehicles will use this protocol to communicate. At the moment, however, different manufacturers favour different protocols. Table 1, below, describes which OBD II protocol is favoured by which manufacturers. Please note that this list is not exhaustive and that there are always exceptions to these general rules.
