Just after posting I realized that I did a poor search the first time around This is better...

http://www.peachparts.com/shopforum/mercedes-benz-sl-discussion-forum/246958-1986-560sl-duty-cycle-madness.html?highlight=ODB

-CTH

Post #2 has a link to build the LED blink code reader.

To access live data, you need a digital scanner capable of comminucating with Mercedes OBD-1 digital systems... something like the Snap-On MT-2500 with 2003 MB software cartridge & cables. This only applies to LH, HFM, and ME injection systems... not the older CIS mechanical injection.

What year/model are you trying to work on? (Hint: It helps to put that information either in your forum profile, or signature.)

:blink:

Such a good post!

I have a 1995 Mercedes E320 cabriolet. Built the scanner which I am trying to diagnose my rollbar and convertible soft top with. I tried to plug my scanner into ports 1, 16 and #2 in the passengers footwell but It won't work, seems like no power at port #2? If I plug into port 9 under the hood, I get a code 1. Is there a fuse for that port ?


Thanks in advance for any info

Just wanted to make sure I understood the basics for finding the cause of the CEL light in my 1993 300ce convertible: After I push the button, I count the light flashes and interpret them using the table [excerpted below] shown in post #1:

Emissions - Using Built-in Diagnostic Module
1 No Fault Found
2 Heated oxygen sensor faulty
3 Lambda control faulty
4 Air injection system faulty hot film mass air flow sensor with hot wire
5 Exhaust gas recirculation faulty
6 Idle speed control faulty
7 Ignition system faulty
8 Engine coolant temperature sensor open circuit
9 Intake air temperature sensor, open circuit
10 Voltage at mass air sensor too high/low.

Thanks.

Those are correct, although you only list the first 10 out of the 26 total codes for the DM on a W124 with M104 HFM motor.

Use the PDF in post #19 above.

:nuke:

thanks for responding. What is HHT?

Hand Held Tester. It was a factory Mercedes tester and coder, until replaced.

More pics here:
Mercedes Benz Hand Held Tester

:-) neil

Another Update
 

Great info in this forum. Hope I can add positively to the contribution of ideas.
code reader
So I needed a OBD I blinker code reader for my 94 until I get the actual scanner. Wanted to check to see if there were any codes although my check engine light is not on. Found this thread on how to make a code reader as well as several others and proceeded to make my own.

I wanted to share my findings in the event that others may find them useful. I kept things Mercedes, rather than get the requisite parts from radio Shack, and to keep an MB flair I opted to re-purpose a common Mercedes dash switch for this tool. In my case I had a spare w124 Rear Window Defogger switch, but a Air Recirc switch or likely any other MB momentary dash switch with LED indicator would work.

Open the switch and make a few changes with a soldering iron. All the parts you need are already in the switch. The RW Defogger switch has (2) LEDs, and (2) LED resistors. Add a small wire connecting bridge and your are done. Same holds true for an Air Recirculation switch.

Tester works like a charm, tested and came up with 1 blink across all areas, No Codes :D

I attached a couple of pics for your reference. The Probe lead (for 8 & 14) is the one side of the switch contact and ground is the other. Enjoy

[IMG]http://i89.photobucket.com/albums/k2...BlinkerFin.jpg[/IMG]

[IMG]http://i89.photobucket.com/albums/k2...DBIBlinker.jpg[/IMG]

EDIT
If you really want to get snazy and either have an extra spot on your center console switch assembly or simply dont need a RW Defroster. you could wire the switch directly to lead 8 and 14, and since this switch is a double trow momentary, you can read your fault blinks from the comfort of the cabin, one direction for pin 8 and the other for pin 14.

Reader with series resistor.
 

Here is an image that may be easier to read for many people...
This one uses a standard LED any color, with series resistor of 1k
The enclosure does not exist in this ilustration, that's up to you...

http://www.kj6zd.net/wp-content/uplo...ode-reader.png

Any Light Emitting Diode, except with already built in resistor, can be used.

You'll need three banana plugs as shown.
One momentary push button
One 1k 1/4W resistor
One LED color of your choice any size.
Wire as in the image and it will work.

Cheers,
have fun with the project...

I built this tool this evening to help further diagnose a DM code #6 (the idle on my 94 e320 wagon has been really high). It appears to work on pin #6 and #7 (Pin #6 returns 8 flashes and pin #7 returns 1 flash). However when I try on pins 14 and 8 I get no feedback, not even a single flash. Any ideas why I wouldn't get any feedback from these pins?

**Update** - I went to radio crap and bought the specific LED as per the instructions earlier in the thread and that fixed the problem.

Put an ohmmeter between the black ground wire on your tester and the wire that you move around. Press your momentary contact switch and check that the resistance goes to zero. If it does not, then that could be your problem. Use the lowest range on the meter. I built one years ago and included a 250ma fuse in the test line. The resistance of the fuse was enough to keep it from working on some of the pins. Changed fuse to 1 amp and all was well.
You could have a switch that has oxidized contacts adding unwanted resistance.

I have fan blower motor and air conditioning and heat not working in my 1994 MB E320 (W124). I have installed a new strip fuse 30 Amps (part # 000-545-20-34) in front of fuse box. It is still not working. Are there any more fuses or relays in this circuit I should check? Any other thoughts?

95 e320 w124 17 malfunction between individual control module
 

does anyone have a clue

Clear the code and see if it keeps returning. If so, you'll need to check codes on the other modules.

If the car is running normally, you can just ignore the CEL, unless it has to be off for an emissions test.

:stuart: