Introduction to On Board Diagnostics (II)

OBD II for L & MD VehiclesSTD ManualUniversal Interface for OBD II SCan Tool:SAE J 2201 defines the vehicle communication interface for OBD II Scan Tooldescribed in SAE 1978. This interface connects the SAE J 1962 test connector to thehardware/software of the SAE 1978 OBD II Scan Tool which will use uthis interface tocommunicate with vehicles for accessing required OBD II functions. The interfacedefines several standard terms and interface functionality. The standard describes indetail the software requirements of the program in the PCM that facilitatescommunication between the Scan Tool (external) and the internal OBD IIcomponents in the vehicle. The medium of communication is the serial data linkdescribed in SAE J 1850.The standard defines the required message structure support, signal ground, chassisground, cable length of the Connector to Scan Tool, and other requirements used bySAE J 1978 Scan tool.Appendix A of the standard gives examples of interface implementation that havemet the requirements of this standard.