Removal and Replacement

91-622 Removing And Installing ETR Control Module Or ETR With Airbag Control Module

Special Tools:

Commercially Available Tools And Testers, MB Testers:

A diagnostic routine is integrated in the control module which tests the control module and the electrical components of the airbag system. If a fault is detected, the SRS malfunction indicator lamp (A1e15) does not go out after not more than 20 seconds. The faults detected are stored and can be retrieved as a pulse readout using the malfunction indicator lamp (A1e15) or as a digital readout using a pulse counter. See Diagnosis Manual Body for testing.

Note regarding pulse readout
The digits from 1-10 appear in the display of the pulse counter.

The digit 1 means that no system fault is stored. All the other digits are assigned to a particular type of fault. If there are several faults in the system, the fault with the lowest pulse number is indicated first.
- If the battery voltage LED comes on after connecting the pulse counter, the pulse counter and voltage supply for pulse counter are in proper order.
- If the first digit again appears during the test after at least two or more pulse readouts (digits), all the faults have been displayed.

Pulse readout diagnosis
- Connect pulse counter as shown in the connection diagram.

NOTE: Battery voltage LED in display panel must light up.

- Switch on ignition
- Press start button for between 2 and 4 seconds.
- Readout 1, no fault in system. If a different digit appears, rectify fault as described in Diagnosis Manual Body.

Testing after replacing control module (vehicles as of approx. 07/93)
After installing a new control module, it must be programmed and parameterized with the hand held tester (HHT) as specified in the Diagnosis Manual Body.