You need to connect the LED between the battery pin #3 and the pin you need to read with the IGN on pos 2.

E.G. to read the ASR codes on pin #6 you would need to connect the LED between pin #3 and #6. Short out the the LED connection to pin #6 to ground for around 4 seconds, if it blinks once you're in luck. If you get more than one blink, short out pin #6 to ground for about eight seconds to clear that code, then read it again, if you get more blinks keep shorting to ground until only one blink is recorded. if it continues to give more than one blink, look up the blink code that is listed in the sticky that you read (DTC codes).

This method applies to all of the pins applicable to your vehicle.

 

ha...ok I think I get it now...

So you hook up the + lead of the LED to 12v (aka pin#3) and the - lead to the pin you want to read then then ALSO use another wire to short out the pin you want to read (where the - side of the LED) to ground (aka pin#1).

That makes a lot more sense now Normally I am really good with this kind of stuff but this was just baffling me completely because I couldn't figure out how the circuit would be completing itself to get a reading. I had read somewhere that someone else had hooked it up wrong and blew fuses and stuff so I was scared to try anything else. The last thing I need is a SL600 with fried electrical components!!!

thanks Redliner for the clarification :thumbsup:

 

I have tried searching until my eyes have gotten blurry for several days and just can not find what the codes mean that I am reading with the led test light that I put together from instructions from this site ,but, they are doing me no good if I dont know what the codes represent. could someone paste a link that will direct me to the correct page so that I will know what to do with the codes that I am getting off of my 95 sl500 5.0 engine PRETTY PLEASE
THANKS
Bill

 

Bill, it's a learning curve that many of us have had to follow too

I've extracted the DTC codes from the sticky which you will find as the attached pdf file. edit: attached in the following post

There are 169 pages but you can narrow things down for your own particular model and year.
If you look at page two you will see the heading "Analog Fault Codes", this is divided into sections which actually represent each pin of the socket you are reading.

An example:- Reading down on page three you will find ELECTRONIC ACCELERATOR / CRUISE CONTROL / IDLE SPEED CONTROL (EA/CC/ISC) w/ASR underneath this heading you will see the following:-
124 129 140 202 1992-97 . . . . . . . . . . . . . . . . . . . . . . . . 47

You will now see that this applies to your model and year, and to go to page 47.

On page 47 headed Cruise Control/Idle Speed Control (CC/ISC) w/o ASR underneath find the dialogue box Connect wires of scanner as follows (129 38pin socket)

It states that you connect to PIN 7

Below that is the FAULT CODE TABLE
If when you connected to pin 7 and your LED blinked 5 times, look down the fault code table for number 5.
5 Stop Lamp Switch this indicates that you have a potential problem with the stop light switch (which we all know can make the ASR light come on).
Clear that code and then read pin 7 again for any other codes, just count the blinks and check the number of blinks against the FAULT CODE TABLE Clear the codes by shorting to ground for about 8 - 10 seconds and read pin 7 again, if say you still get 5 blinks then you would consider replacing the stop lamp switch.
If you only get one blink the stored codes have been cleared and there are no faults.

This method applies to all of the pins on the 38 pin socket that are relevant to your make and model.

 

I bought a code reader through eBay that came with directions. It works well, but there was a "wrinkle" with my '95 SL600: I had to turn off the ignition after clearing each code. Otherwise, they would continue showing-up with the reader. :surrender: Also, I got some different codes than those for my car. But, they all went away when I rewired the cable to my MAF.:thumbsup:

 

Oops I didn't attach the pdf file

 

Many thanks
Thank you for the post, maybe I will figure out this new fangled machine before technology passes me by.
Thanks
Bill

 

My 95 SL500 started acting up again, this time the mpg,speedometer,odometer,asr,cruise control quit working then it went in and out of limp home mode a few times then stayed in limp home mode. Replaced the engine wiring harness which was in bad shape but same problems existed. Then I pulled on a large wiring harness that went from the top of engine to a round connector mounted on top of the passenger side fender well and it came apart with no force at all, reseated the round connector firmly and everything started working. Maybe this will help some others with same kind of problems. Thanks for everyones help I was able to fix a few other problems along the way.

 

Thanks for that tip, the harnesses of these models in theory should have been recalled and changed FOC by MB for those particular MYs.

 

Hi
I bought a 500 SL model 1993 with LH fuel system injection not the previous system.
My car started to misfire with intermittent and now is always misfiring. I changed ignition coil, spark plugs, wires, but still acting up. I am still not doing the compression test.
I bought a basic diagnostic tool including the led system that blinking for 40 $ from ebay and i hope to resolve the problem. Is there anyone had use this tool???

Adam from France

 

Hi

I bought a basic diagnostic tool including the led system that blinking for 40 $ from ebay and i hope to resolve the problem. Is there anyone had use this tool???

Adam from France

Just look at the posts above yours

 

IF you changed only one coil there is a second one that could be causing a problem. Yes, many here use the code reader. Did it not come with any instructions?

 

The other coil is new, now i have 2 new coil. I just bought the code reader, i am still waiting the tool.
I will let you know.
Thank you for your answer.:thumbsup:

 

Hi guys,Great thread.
I have a C180 (202), that cranks but will not start. Fuel pump does not come on(it works,tested) and coil does not get power. I tried to read the error code from the 38 pin socket and have the following problem. Socket 23 (ATA) was tested perfectly as per forum suggestions and I cleared the 3 errors, now it gives me one blink which is perfect. However when testing all the other sockets I notice the LED lights up very dim.When the ignition is turned on to position 2 the light goes off. After shorting the LED comes on but never blinks. Please help with suggestions