INTRODUCTION
Parameter Identification (PID) mode allows access to certain data values, analog and digital inputs and outputs, calculated values, and system status information. There are 2 types of PID lists available. The first is a General Motors specific PID list that can be accessed by using a Tech II scan tool. The second is a Generic OBD-II PID list. This is a standard set of PIDs that all manufacturer's scan tools can access.
PID VALUE tables are used for diagnosing intermittent symptoms and faults that are unable to be resolved during self-diagnostics. PID values are continuously updated when accessing PIDs from a specific PID list. Before performing tests, ensure engine mechanical condition has been inspected and self-diagnostics has been attempted. Technical Service Bulletins (TSBs) may also be helpful in correcting a hard to diagnose problem.