Description of On-Board Diagnostics

Introduction

The Testing and Inspection Procedures of the OBDII, DME System ME 7.2 is used for the systematic troubleshooting and elimination of faults in vehicles with engine management ME 7.2.

Structure

The troubleshooting and elimination of faults Procedures are subdivided into several sub-categories:
- Definitions and General System Requirements
- Function Description of Sub-systems
- Engine Specifications
- Engine Specific Load Values
- Porsche System Tester 2, Description
- Tester Display, Data Output For Specific Tester
- Component Location
- Tools
- Troubleshooting

The troubleshooting category is subdivided into several sections:

1. Service Number
The individual fault listings are assigned a 4-digit service number which coincides with the labor and damage codes in the Suggested Repair Times Catalog

Example: 28 73







2. Diagnostic Trouble Code (DTC)
The standardized 5-digit Diagnostic Trouble Code is stated.

3. Fault Text
Here the text is shown as it appears in the system tester display.

4. Function Description
A brief function description of the component or sub-system is shown (e.g. misfire detection).

5. Diagnosis Conditions
Here the conditions are described under which the diagnostic routines are run by the DME control module. It is important, for example, to reach the driving ranges or operating conditions during a test drive to make the diagnosis possible.

6. Fault Table
The fault conditions and fault areas are described for each Diagnostic Trouble Code in a fault table.

7. Wiring Diagram
A partial wiring diagram is shown containing the component or sub-system with the respective wiring to provide a quick overview.

8. Diagnosis Procedure
In the diagnosis procedure section, troubleshooting is described systematically and in a clearly arranged manner.
If the Check Points require further explanation, they are allocated a number.
Check Points with a number are fully explained at the end of the manual.

9. Check Points
Full explanations of some Check Points.
Assembly work is not described here.
Troubleshooting is described for the use of the Porsche System Tester 2 because it offers considerably more functions than a generic scan tool. Troubleshooting and repair are, however, also possible with a generic scan tool.