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2007 ML320 CDI, 2001 CLK 55 AMG
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Discussion Starter #1
My 2001 CLK55 just started showing ABS, BAS, ESP malfunctions yesterday. Went over to my mechanic to have him plug in OBD2 for a code read. First went under the dash and plugged in... wouldn't communicate; then went under the hood to the factory plug (the big round one) and it also wouldn't communicate.

Has anyone had such a communication problem?

p.s., he said they get lots of MBs with those three malfunctions; and I've read posts here saying it's the brake light switch, but all my brake lights work.
 

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99CLK320
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1,480 Posts
I have had trouble getting the dash receptacle to connect but I just have to hold it up in place. I don't have an adapter for the engine port. Where can I get one? Sounds like you have a code reader issue not a car issue. try it on someone elses car and that may tell you.
 

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2007 ML320 CDI, 2001 CLK 55 AMG
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Discussion Starter #3
My mechanic tried two different OBD2 code readers; one for the under dash plug, and then a different one for the under-the-hood Mercedes plug. Neither of them would send info to the readers.
 

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92 190e 2.6 Sportline, 2005 clk55
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Just recently had my car in the shop and the star reader was not seeing the fuel card. He pulled the power cable from the battery and re seated the card ad all is good now. You might try disconnecting the battery for about 10 min and trying again. Also try turning your wheel all the way left then right then left again.
 

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92 190e 2.6 Sportline, 2005 clk55
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thats a 5 dollar part easy fix imo if it fails it should make you tranny have issues
While I agree that this is a cheep fix I don’t think it is his issue. Also there won’t be transmission problems per say but you wont be able to move the selector out of park because the car won’t know that the brake is depressed.
 

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'01-E320 & 02-ST2
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There's a lot of speculating about the BLS, and while it's actually closer to $25, it's also the first thing I'd suspect and then change. The car uses inputs from the switch for lots of different things, and if it gets a hokey signal at ANY point, it will fail that test. For the brake lights and shifting out of park it doesn't matter; when it gets a clean connection, the lights go on and you can take it out of park. But for safety systems like ABS, BAS, ETS, ESP, etc. if it doesn't get a good signal then it fails the circuit and the system.

With all the fiddling around trying to get a code reader to work the BLS could have been changed about six times.

I'm not trying to tell anyone how to proceed. All I know is, I carry a spare BLS in my trunk (dealer part is best, the aftermarket ones are really troublesome) and if it were my car with those symptoms, I would have already changed it.

(Then in my leisure time I'd start testing fuses to see if one of them is killing power to the diag ports.) ;)

Good luck.
 

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2007 ML320 CDI, 2001 CLK 55 AMG
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73 Posts
Discussion Starter #9
Wouldn't you know it. After three days of the ABS/ESP/BAS malfunctions staring me in the face, I start the car to go on an errand and the malfunctions have gone away. Everything looks normal.

I'm going to buy my own OBD2 and see if maybe the ports are working now, as well. This car has me scratching my head occasionally. But I like it when it fixes itself. When I was twenty I bought myself a 1960 Alfa Romeo Giulietta Sprint Veloce - 1300cc, dual Webers, 5-speed, high compression, and noisy. I paid $1200 for the little red beauty. One day for no good reason, the driver door refused to open. Stayed like that for a couple days, forcing me to crawl in from the passenger side, while I scratched my head wondering what to do. Then it just fixed itself. This CLK is the same way. First the driver seat stops; I'm just about to loosen the nuts to remove the fore/aft motor, try the switch one more time.... it works! And now with the malfunctions suddenly disappearing. Is it possessed?
 

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Mercedes S320 CDI 2007
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111 Posts
No it's not possessed.

Some of the parts are wearing out (like the brake light switch) & are intermittent - which means that they will start off failing now & then, over time it will get worse.

That fault that just 'fixed itself' will come back more & more frequently until you are stranded somewhere in park.... cursing why you did not fix it when you got the first warning sign.

My advise? Get the switch changed NOW whilst you have a working vehicle.

Any other faults that mysteriously 'go away' should also get investigation, and if the result is a likely £20 fix & 15 minutes of time, I know what I would do.

Matt
 

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2007 ML320 CDI, 2001 CLK 55 AMG
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Discussion Starter #11
Just got back from MB dealer and now have a new brake light switch to be installed this weekend. Still haven't re-tried the ports to see if they're communicating, but will this weekend with my son's OBDII.

Thanks all for the advice.
 

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'01-E320 & 02-ST2
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Just got back from MB dealer and now have a new brake light switch to be installed this weekend. Still haven't re-tried the ports to see if they're communicating, but will this weekend with my son's OBDII.

Thanks all for the advice.
Pulling and testing the fuses is easy enough, just use an Ohmmeter to check them. They can look okay and not be good. ;)

Check them one at a time, that's the safest way to proceed. :D

BTW, if you want a basic code reader, this one is under $20. It will read and clear codes, though it won't do advanced diagnostics...but then it doesn't cost $150 either. ;)

Autel MaxiScan Code Reader at Amazon


Good luck.
 

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2007 ML320 CDI, 2001 CLK 55 AMG
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Discussion Starter #13
I have a fuse tester and checked all applicable ones. Usually the cigar lighter fuse is also for the diagnostic ports, from what I'm told.
 

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2007 ML320 CDI, 2001 CLK 55 AMG
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Discussion Starter #15
I borrowed an OBD II code reader. When plugged in with ignition on, gives "Linking error" just like it did when I took it to my favorite mechanic. I then started the motor and it worked. The documentation for the reader says car can have ignition on or engine running. That got me thinking about voltage so I did a static check on my battery and it read 12.35 volts. Could it be that that little bit low voltage stopped the communication port from working?

Seems to me it should be higher so I'm off to Autozone or ?? to do a proper battery test. The motor has turned over a little longer before firing up in the past few days on at least a couple occasions.
 

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2002 CLK 430
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191 Posts
I have a new battery, etc. I also get a linking error with my OBD scanner unless my car is running. Though it will only connect this way, I cannot get further diagnostics - I think that is a problem with buying a $75 POS off of eBay. Though the linking error while the key is just in the 'start' position, no engine on, I don't think is an immediate indicator of a battery problem.
 

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2007 ML320 CDI, 2001 CLK 55 AMG
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Discussion Starter #17
Well, the battery was bad (had it tested under load at two different stores - it was five plus years old)... so I have a new Interstate battery. The car was back in the shop for valve cover re-sealing and spark plugs. The diagnostics said one of my cylinders wasn't right (coil or injector problem is suspected - replaced the plug wires to that cylinder so that wasn't the issue). I can hear and feel the slight roughness at idle, but I'll be darned if I can remember whether it was like that before. Still lights up the tires, but now it seems I have another problem to chase.
 
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