1994, C280: No Communication with ECU

[Arv]

Hi All:

I have the Check Engine light on far like zillion years. Few times, I had the oxygen sensor changed to fix the problem, but it still kept coming back on, so finally I decided not to worry about it. Now, this was very long time ago may be almost 10yrs ago. The car runs fine mostly and I get very good mileage also, 26/27 mpg hwy/city combined and even higher for hwy driving. I get the SRS light on intermittently and every once in a while it stalls.

Recently I saw an ad for free code scanning from a shop so I went by there yesterday just to see what all codes I get. The shop had A Solus scanner made by SnapOn Tools. He connected the scanner to the round diagnostic connector under the bonnet and tried to retrieve the codes 3-4 times, but kept getting "No Communication". The mechanic also tried the rectangular connector under the steering but got the same error.

What could be the problem?

Thank you all for your help,
Arv.

 

[Alex Crow]

could be a blown fuse for the socket power supply. you should have 12v between pin1 and pin3 if i remember correctly. alternatively the snap on scanner may well be incompatible - they are not the best.

 

[Arv]

Thank you for your reply. I have checked all the fuses and they are good. I had gone to a major national chain auto shop. Assuming the scanner was working properly, is there anything else that could be wrong?

Thank you,
Arv.

 

[television]

You say that you have a connection under the steering ?

 

[kth286]

where exactly is your location in the world ?

 

[Alex Crow]

florida, could be worse huh? guess the usa cars get the obd socket from way back david?

 

[television]

My 1999 129 had the cut out in the under dash card, but MB did not fit them to any UK car designed before 2000, no cars were modified in production for this for the UK

 

[Arv]

Yes, Malcolm, I have a rectangular socket under the steering as well and a round socket under the bonnet. I live in sunny South Florida about 80 kms north of Miami.

Is it bad to have rectangular socket under steering? Does it mean Mercedes is selling us old technology?

Thank you all again,
Arv.

 

[kth286]

Arv

You were ahead of us in Europe, as we did not get that till much later.

However, we can get codes from that generation of cars using an LED blink tester on the 38 pin socket. you just need the codes so that you know what the number of led blinks mean.

Google Merc blink codes and see what you find.

 

[Arv]

Thanks David. Why do you need to diagnostic sockets anyways? I assume they test diff systems, but they could have just done that with one socket as well.

Cheers,
Arv.