Scan Tool Failure Due To Improper Hook-Up (54/71)

SCAN TOOL FAILURE DUE TO IMPROPER HOOK-UP

TECHNICAL SERVICE BULLETIN

IMPULSE COUNTER SCAN TOOL FAILURE DUE TO IMPROPER HOOK-UP

Model(s): 1992 Mercedes-Benz 400 SE; 1992-93 Mercedes-Benz 300 SD, 300 SE, 500 SEL, 600 SEL; 1993 Mercedes-Benz 190 E, 300 D, 300 E, 400 E, 500 E, 300 CE, 300 TE, 300 E 4MATIC, 300 TE 4MATIC, 400 SEL, 500 SEC, 600 SEC, 300 SL, 500 SL, 600 SL

Group: 54 - Electrical System

Bulletin No.: 54/71

Date: August 1993

SERVICE INFORMATION

• Special Tool - 124 589 19 21 00

As described in the Diagnostic Manual, connect the yellow lead (signal) to only those sockets from which DTC's can be read. The terminal layouts for the 38-pole diagnostic test (data link) connector shown on page 372 of the Model Year 1992, Model 140 Introduction Manual and on page 81 of the Model Year 1993 Models 124, 129, 140, 201 Introduction Manual are invalid. (Socket 2 is for voltage from circuit 87, not for checking the base module. Refer to section 0 of the respective Diagnostic Manual for complete terminal layout identification.

A short in the signal input circuit can be caused as follows:

1. Connecting the yellow lead to socket 16 (circuit 1) of the 16-pole data link connector (X11/4).
2. Connecting the yellow lead to socket 2 (circuit 87) of the 38-pole data link connector (X11/4).

Protect the impulse counter scan tool from incorrect hook-ups as follows:

1. Install a commercially available in-line fuse holder (Radio Shack 270-1281 or equivalent) with a 3 amp fuse (Radio Shack 270-1276 or equivalent) in the yellow lead. (Solder the fuse holder into the lead and cover with heatshrink tubing).
2. Insert a solid plug, such as a section of O-ring, into socket 2 Fig. Fig 1 ) of the impulse counter scan tool adapter part no. 140 589 14 63 00.