Introduction

The specific engine control system you happen to be troubleshooting/diagnosing dictates what method of diagnostic procedure you must follow.
Before the DIS was available, the Diagnostic Manuals provided information for diagnostic procedure. There are Diagnostic Manuals for the E32/34, E36 and E31 vehicles. These manuals are still an excellent source of information for pre DIS systems.

The Diagnostic Manuals provide:
- System Functional Descriptions
- Info on the control module's diagnostic system.
- Abbreviations pertaining to system
- Control Module Pin assignments
- Troubleshooting test procedures with nominal values
- Defect/Fault Code explanations
- Component testing information Technical Data

With the introduction of the DIS all of the Diagnostic Manual information was incorporated into the DIS software. Data communication with a specific control module provides an up-to-date system specific interface. The DIS provides Fault Symptom troubleshooting procedures with access to Fault codes, Status Requests, Component Activation, Special Service functions, etc.

This section provides information regarding how the control modules communicate diagnostic information and/or fault recognition to the DIS and with each other via CAN communication.

Additionally, Engine Control Module Variant Encoding (M1.x) or Control Module programming (> M3.x) is another topic that must be considered when diagnosing a system. If a control module has been coded or programmed incorrectly, it could possibly induce driveability complaints and or incorrect system function.

Finally, this section provides examples of using the Diagnostic Manual "Paper" information method in conjunction with the DIS and a system using the "DIS" alone.