Diagnostic code reading has been discussed many times on this site. A lot of problems with our cars can be checked by doing this. this will work on cars up to about 1995.
I am sure many of you have already made your own code reader and know how valuable this can be. I hope some of you will photograph and post your code-readers as well for the benefit of anyone wanting to make one.
If you have not got your own, it's not that daunting a task. please read on and check the photos.
I made my reader following Bobterry99's advice on this site, and also with reference to this gentlemans website: http://pages.prodigy.net/jforgione.MS_S500.html
The steps to making a code reader are as follows:
1. Print out the following circuit diagram and take to a good electronic store that have good staff to help. R1 is a resister. F1 is a fuse. D1 is a LED. S1 is a momentary switch. Get three banana plugs and 700mm - 1m of wire. The blue numbers refer to part numbers at a particular shop because the diagram is stolen from the website above.
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(There are different ways of making a code reader. Bobterry seems to have a LED with a resister in-built and leaves out the fuse because it is not needed. the LED/resister would be good to get. the fuse I'll leave up to you to decide.)
2. I soldered mine together as shown in the photo and placed into a black box. black is good because it makes reading the LED easier.
3. The diagnostic unit that this plugs into is under the bonnet to the right of the engine on the firewall. the cover just pulls up. on my 1990 500SL the unit has 16 sockets. later models have 38 (i think).
4. on my 16 socket unit I plug the red banana plug into 16 (Battery). the black banana plug into 1 (ground) and the yellow banana plug into the socket that you wish to test.
This is really all there is to it making it. simple and cheap. about US$10 all up and most of that was for the box.
This next part is about how to use it. BUT, I would encourage anyone wanting to do this to read previous posts by Bobterry99 on the subject. My knowledge on this part is only VERY BASIC.
5. Push the momentary switch for 2-4 seconds. This shorts the battery to the ground and starts the code. (don't worry, apprarently you can't damage anything). once the switch is released the LED will blink.
6. One blink appears to mean that everything on that socket is okay. more blinks are a code, write it down.
7. only one code is shown at a time. So repeat, and more codes might come. or not if nothing else is wrong.
8. to clear codes just push the momentary switch for about 8 seconds after you read each code.
Wonderful tool. Now if only i knew what each socket was for and what the codes mean!
here are the photos:
I am sure many of you have already made your own code reader and know how valuable this can be. I hope some of you will photograph and post your code-readers as well for the benefit of anyone wanting to make one.
If you have not got your own, it's not that daunting a task. please read on and check the photos.
I made my reader following Bobterry99's advice on this site, and also with reference to this gentlemans website: http://pages.prodigy.net/jforgione.MS_S500.html
The steps to making a code reader are as follows:
1. Print out the following circuit diagram and take to a good electronic store that have good staff to help. R1 is a resister. F1 is a fuse. D1 is a LED. S1 is a momentary switch. Get three banana plugs and 700mm - 1m of wire. The blue numbers refer to part numbers at a particular shop because the diagram is stolen from the website above.
[
](There are different ways of making a code reader. Bobterry seems to have a LED with a resister in-built and leaves out the fuse because it is not needed. the LED/resister would be good to get. the fuse I'll leave up to you to decide.)
2. I soldered mine together as shown in the photo and placed into a black box. black is good because it makes reading the LED easier.
3. The diagnostic unit that this plugs into is under the bonnet to the right of the engine on the firewall. the cover just pulls up. on my 1990 500SL the unit has 16 sockets. later models have 38 (i think).
4. on my 16 socket unit I plug the red banana plug into 16 (Battery). the black banana plug into 1 (ground) and the yellow banana plug into the socket that you wish to test.
This is really all there is to it making it. simple and cheap. about US$10 all up and most of that was for the box.
This next part is about how to use it. BUT, I would encourage anyone wanting to do this to read previous posts by Bobterry99 on the subject. My knowledge on this part is only VERY BASIC.
5. Push the momentary switch for 2-4 seconds. This shorts the battery to the ground and starts the code. (don't worry, apprarently you can't damage anything). once the switch is released the LED will blink.
6. One blink appears to mean that everything on that socket is okay. more blinks are a code, write it down.
7. only one code is shown at a time. So repeat, and more codes might come. or not if nothing else is wrong.
8. to clear codes just push the momentary switch for about 8 seconds after you read each code.
Wonderful tool. Now if only i knew what each socket was for and what the codes mean!
here are the photos:
