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Diagnostic ports & building a code reader

54K views 19 replies 14 participants last post by  elCheapoDeluxe  
#1 · (Edited)
Someone on another forum asked me to provide details about the diagnostic ports and the building of a code reader for my '88 560SL. Thought it might be a good idea to have it here too.

Len

Keep in mind I'm talking about my '88 560SL here. Not sure all years have things in the same location. I found the nine pin diagnostic port on the driver's side fender well. It has a screw on cap. See first photo. This diagnostic port reads engine duty cycles only. You can buy a multimeter that has the duty cycle function or if you have a dwell meter, you can use that since it also reads duty cycles.

The second diagnostic port was right in front of me, but much as I looked, I couldn't find the darn thing. See second photo. It is about three inches forward of the first diagnostic port on the driver's side fender also. It is covered with a plastic cap that deceived me into thinking it was something else. Many have said that they found this second diagnostic port on the passenger side on the firewall on other Mercedes of that same era. This second diagnostic port is the one you need the blink code reader for.

The following links will describe the parts needed to build your own code reader and instructions on how to do it. I bought all of my supplies at Radio Shack for under twenty bucks and built it in an hour or so.

http://www.geocities.com/MotorCity/Downs/1039/mercedes/cs1000_mb.pdf. These are the instructions from Mercedes for using the code reader. Only pages 9, 10 and 113 applied to me.

K6JRF Auto Page. This is a good page on code reader's in general and also gives the procedure and parts needed to build your own.

http://mywebpages.comcast.net/chwilka/Error_Code _reader_reset_tool.htm. This one takes you through the SRS problem on an '89 560SEC and has some good pictures and instructions.

That ought to do it.
 

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#11 ·
AFAIK they do not exist. The round plug is not used to access stored codes. As Len stated.

"I found the nine pin diagnostic port on the driver's side fender well. It has a screw on cap. This diagnostic port reads engine duty cycles only. You can buy a multimeter that has the duty cycle function or if you have a dwell meter, you can use that since it also reads duty cycles."
 
#12 ·
How do i use the diagnostic port on my 85'190e 2.3?

Hello forum people. :) Does anyone know where i can find sokoloff's geocities pdf link again.?? The geocities link is broken. I would like to know how to use and read my diagnostic socket on an 85' 190e 2.3.

Broken link:
http://www.geocities.com/MotorCity/D.../cs1000_mb.pdf. These are the instructions from Mercedes for using the code reader. Only pages 9, 10 and 113 applied to me
 
#18 · (Edited)
Does anyone have any thoughts on the "code 10" aka "control unit has been activated" code?

I created my own little test rig (didn't have any 12v LEDs so I just used a 12vdc Omron relay which one can either look at the indicator on the top or just listen for the clicks) and a spare light switch. Tip for anyone who wants to make their own rig of any sort, speaker banana plugs work PERFECTLY for inserting in holes 1 and 6. I am kind of a speaker-head so I have many types in my home, but these are my favorites. https://smile.amazon.com/Sewell-Deadbolt-Banana-Fast-Lock-Technology/dp/B00FF3UN72 They are nice and snug.

I was able to clear codes 3, 5, 6, and 9. Obviously was not able to clear code 10. Would like to know if there is anything to be done or if I just have to search for a new control unit. I imagine this is a pricey part, and getting one used is probably a crapshoot.

If I hadn't put the new carpet in I wouldn't have had the center console unplugged and if I hadn't done that my turn signals wouldn't have stopped working and if I hadn't put a dash cap on I wouldn't have had my instrument cluster out and if I hadn't had my instrument cluster out I never would have been poking around back there thinking that's where my turn signal problem was and if I hadn't been poking around I never would have noticed the loose wire without a bulb that went to my SRS light and if I hadn't noticed that I never would have put a bulb in there and found out my SRS wasn't working for probably quite some long time causing someone to remove the bulb from the dash. Maybe I should just remove the bulb from the dash - but the reason I bought the 560sl to begin with is that I wanted ABS and an airbag. No good deed goes unpunished. Ugh.

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