What codes can be pulled on a 1991/92 129 500SL?

[speace]

What diagnostic codes are available for the 91/92 500SL?

I am combining 91 and 92 in this thread because I believe these two model years have identical systems and diagnostics. (Tell me if I am wrong!)

First off, I want to say that at this time I am not currently troubleshooting any particular problem. (Thank goodness!)

Over the years I have experienced ASR, ASR/ABS, Soft Top, and Rollbar problems on my 92 500SL. Each time, I have had my shop deal with the fault, but I want to learn all about the available diagnostics on my car to be prepared for whatever comes along in the future.

I have a rectangular block with (16?) numbered holes near the firewall on the passenger side of the car. It appears I can insert a wire or 'probe' to monitor something, or invoke a diagnostic system. This car does NOT have the 38 pin round connector. That starts in 93 on the SL series.

The 91/92 SL models have the CIS fuel injection system with the fuel distributor.
The throttle is controlled by an "ETA" that is controlled electronically. Failures in this system usually result in the ASR light being on and the engine goes into "limp home mode" when an ASR or ETA problem is sensed.

It is my hope that this thread will serve as reference for all who have tips for diagnostic problem-solving on this one model.

I expect there are codes for the ASR system, the soft top and rollbar, and perhaps the ABS system.

So, how do we access these various diagnostics and where ido we find a resource for the possible codes?

[Arthur Dalton]

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http://members.aol.com/ajdalton7/ledtool.jpg

http://www.geocities.com/MotorCity/Downs/1039/mercedes/cs1000_mb.pdf

[speace]

Thanks for the links, Arthur!

So, we build the LED tool with the three banana plugs using Arthur's first link.

For the 1990-1992 R129 cars the diagnostic port is a rectangular block with 16 holes in it that is located under a cover near the firewall on the passenger side (LH Drive). This is very close to the electric switch that senses if the hood is open.

To connect the tool, we connect the black plug to pin 1 and the red plug to pin 16.

The third plug (Let's say it is yellow) then goes into the socket for the system we are troubleshooting.

Using the Chassis code of 129-066 (for a 90-92 R129) we can locate the pages in the CS1000_MB.pdf in Arthur's second link that are relative to the system in question.

For the CIS System we use pin 3 * corrected by post #4
For the Roll Bar System use pin 7
For the Soft Top System we use pin 10
(Edit: See post #6 for the entire list and pdf page numbers)

TO READ THE CODES:

Press the button on the LED test tool 2-4 seconds and release.
The LED will blink out all stored codes.

To RESET THe CODES:
Press and hold the button for 6-8 seconds.

(Sometimes codes must be read twice before they will erase.)

[Arthur Dalton]

Pin 14 is EA/CC/ISC.
CIS should be pin 3...............

[compress ignite]

AD,

Thank YOU!

[speace]

Originally Posted by Arthur Dalton

Pin 14 is EA/CC/ISC.
CIS should be pin 3...............

Thanks, Arthur

I have corrected that in the above post.

I dug through the entire PDF searching for 129.066 codes (90-92 R129)

Here is the entire list. The page numbers I reference match the PDF but seem to be off by one if you look these up in the index page within the pdf.

-------------------------------------------------------
129.066 codes for CS1000 Scanner PDF document
These pin numbers are for the 90-92 16 pin test connector.

Continuous Fuel Injection System (CFI)
Pg 26/27 Socket 3

Continuous Fuel Injection System (MAS Controller)
Pg 28 Socket 14

Distributor Ignition (DI) LH-SFI
Pg 44 Socket 8

Adaptive Damping System (ADS)
Pg 53 Socket 9

Roll Bar (RB)
Pg 68 Socket 7

Roadster Soft Top (RST)
Pg 69/70 Socket 10

Infared Remote Control for Central Locking (IRCL)
Pg 72 Socket 12

Anti-Theft Alarm System (ATA)
Pg 76 Socket 11