Mode 7

Data Output With A Scan Tool

The output of data relevant to OBD from the control modules was stipulated by law for the USA. It is described in SAE J 1979.

Data output is subdivided into different modes.

Mode 7
Output of test results of continuous tests.

Output of suspected faults.

The data sets in the modes are referred to as Parameter Identification (PID).

After being stimulated by a generic scan tool, all systems relevant to OBD log on with their address. In vehicles with ME 7.8, this is the DME with the address $11 and in Tiptronic vehicles it is the transmission control module with the address $1A.

NOTE: The $ symbol means that a hexadecimal number is involved.

When the control module provides data, it also states the mode, the PID number and the address of the control module.

For example:
Mode 41 PID $01 address $11
Engine control
Number of faults: 0
Check Engine: off

The output of data is carried out:
in Mode 1 with Mode 41,
in Mode 2 with Mode 42,
in Mode 3 with Mode 43, etc.



Mode 7
The fault codes of all non-shedded, officially relevant* faults are displayed in Mode 7. This mode has the same structure as Mode 3.

* Faults which switch on the Check Engine warning light