Test Notes and Definitions

In Pinpoint Tests, a complete description of system operation for each diagnostic trouble code is given. The information given under NORMAL OPERATION describes how the diagnostic monitor functions under normal conditions and how the diagnostic monitor makes its decision to flash out that diagnostic trouble code.

Following the normal operation information is POSSIBLE CAUSES. Possible causes lists failures that may cause the described diagnostic trouble code to flash. Possible causes are listed in the order they are most likely to occur. Much time can be saved by examining the suggested possible causes in the order they appear.

An ELECTRICAL SCHEMATIC is provided to support the normal operation and possible causes information for each diagnostic trouble code. This schematic is broken down to its simplest form showing only components and circuits involved in monitoring for that particular diagnostic trouble code. The circuits shown with dark, heavy lines indicate the circuits that the diagnostic monitor uses to detect faults. Each drawing also contains a "logic box" that is drawn inside the lines that represent the internal parts of the diagnostic monitor. The logic box has "input" arrows and "output" arrows to represent the circuits the diagnostic monitor uses to make its decision. A description (or the logic) of how the diagnostic monitor decides to flash that particular diagnostic trouble code is included in the logic box.