Description of On-Board Diagnostic System

Notes on the BMW DIAGNOSTIC SYSTEM:

*D* Defect Code Memory:

Scope:

The following components are monitored by the system for defects:
- All relays in the relay module
- The turn-catch switches S2
- The limit switches S3

If a defect occurs, the corresponding defect code is stored in the defect code memory.

Clearing:

The defect code memory can be cleared by means of the BMW DIAGNOSTIC SYSTEM. The memory can also be cleared by cutting the power supply to the control module (detach cable or disconnect vehicle battery).

Defects which are attributed to relay sticking cannot be cleared by means of the BMW DIAGNOSTIC SYSTEM. They can only be cleared by disconnecting the power supply to the control module.

Relay defects:

The relays in the relay module are monitored by means of diagnostic lines (diagnostic feedback) between the relay module and control module. In this way it is possible to distinguish whether a relay does not pull up or does not drop out (sticking) after switching off.

*D* Test Procedure:

General:

System components cannot be monitored for defects by way of the defect code memory. Therefore, the defects can be specifically tested following the test procedure.

The diagnostic functions "Status monitoring" and "Component activation" are combined in the test procedure.

Refer to the section "Troubleshooting" for a detailed description of the individual test steps (see defect code 27).
Defect Code 27

Troubleshooting:

Notes:

Refer to safety instructions in "Functional Description"!
Description and Operation

Troubleshooting is mainly carried out together with the BMW DIAGNOSTIC SYSTEM. Observe information provided on the screen pages.

Before commencing with troubleshooting, ensure that the vehicle battery is charged.