ASR problem 600SL please help

[Alans V12]

I have a 1995 600SL with an ASR problem. The ASR light came on the second I reved the engine using the throttle cable. Long storey why I did that but never the less the car was perfectly ok before that. I have now been told by Mercedes that I need a new electronic throttle pedal control unit (£2,500). I can't believe this by just doing what I did. The car only manages 40mph when the light is on. There is no pattern to it becasue some days the car works ok, no light on. It doesn't make any different if the car is hot or cold. I must have just upset something and hopfully it is just an adjustment somewhere.

Mercedes have had the car on their diagnostics and it says there is no reception from EFP N4/1 what ever that is. I have been told it may be the Potentiometer. Can someone tell me what this looks like and where it is. Also I have been told it is the electronic Throttle Actuator. Again can someone tell me what this looks like ans where it is. I will be amazed if I have damaged one of these just by reving the car by it's cable, especially as it is an intermitent fault. The problem is I cannot use the car because I don't know when it is going to come on.

Is there someone out there who has had a similar problem and have cured it.

Thank you in anticipation.

Alan.

[myarmar]

Alan, if I understand you correctly you pulled throttle from the lever under the hood? Mercedes manual warns against doing it as you will set a code and put engine into a "limp home mode". I don't know if this is your only problem, but you need to get it reset and see what happened.
Mike

[Alans V12]

Hi mike,

Thanks for the reply.

Mercedes have reset all the codes but the problem is still there. I have been told that I can bypass the ASR, Don't want the thing anyway, by shorting pin 6 to pin 1 on the control unit. As anyone heard of this and how to do that.

Alan.

[LeaUK]

Alan

Sorry to say but this is one of the most prevalent problems with our SL models! Search this forum first, there are many, many posts regarding ASR problems - and solutions. Search under my name for some interesting reading about simply adjusting the cable - it's not always the throttle unit! http://snipurl.com/atmn

The ASR system is designed to trigger if you rev the engine by the cable as the car doesn't detect the accelerator pedal being pushed - this is perfectly normal. This will set a code but depending on your production date may or may not remember it.

Have a read through Jim's site as it has lots of good techie info on the ASR system... http://pages.prodigy.net/jforgione/MB_asr.html

[anthinhk]

I had a series of problems with my 93 600. I also reved it from the throttle cable, but I was lucky no ASR light came on. The reason people seem to suffer from this problem is because the wiring breaks down over time (the plastic shielding just breaks up and it shorts out). Lucky for me, my mechanic didn't want me to have to spend the thousands of dollars to buy two new actuators (if one goes the other soon follows) so he send it to a computer guy who actually rewired the thing (both sides and main loom) for a few hundred bucks. It's running better than ever now. I only had it done about 2000 miles ago but there is no sign of trouble yet (touch wood). Here is a link to what it looks like and the wring breaking up. http://www.mbnz.org/gallery/showlink.asp?CatID=12228&parentID
=26&subname=SL600_throttle_body_damage&parentname=R129_SL_Class

Hope that helps.

[Gilly]

If you were follow the flow of air you would come to the actuator. It's kind of buried under the intake manifold, down in what I call "the hell hole". It's fine that you don't want the ASR, but in essence you can't just get rid of it. It's an electronic throttle ("drive-by-wire" you might say) and no way to bypass or eliminate it without a huge budget.
I would say that by clearing the codes the problem should be gone. If you have reoccurring problems with ASR lights and linm-home mode, then I'd say the mechanic is correct and more than likely it needs an actuator. I don't know if you caused the problem by tugging on the throttle under the hood or not, but you definitely don't have a unique problem. This is very common on M119 V8's as well as the V12's. The thing to be aware of which I'll share with everyone here, is to make sure (believe it or not) on the V12 that they replace the correct one! The RIGHT ETA is on the LEFT side of the engine (if you study the engine design, the intake manifolds go off to the other side of the engine) and the LEFT ETA is on the RIGHT side of the engine. Pretty confusing. There are other components that work this way on the V12, can't think of what they are right now.
Gilly

[ericgr]

Everyone's posts here are probably very helpful and right-on. I'd like to add one that is more a matter of process than anything. Having been in your shoes but with a different car and different issue, I learned a hard lesson.

First, DO go into the long story of why you touched the throttle if you were trying to solve something. Map-out EVERYTHING you did before the problem occured. Put it on this site. Root cause analysis is, despite what local mechanics argue, very helpful. They treat the symptom, you want to treat the cause. Did you change a filter, move a hose, do anything? What other problem did you think you had, idle, something? Map-out everything that came before it if anything. In my case, there was something I did before that cause my problem but it was not at all obvious that this would have been the cause.

[Kebowers]

The sl-600 is much more troublesome than the 500 and 320 regarding wiring issues for two reasons. 1) there is lots more engine compartment heat which causes the wire insulation to fail sooner, and 2) There is a lot more wiring that has to work perfectly.

The main engine compartment wiring harness is very prone to failure from disintegrating insulation. The part cost is up to about $1700 or so. If the foam insulation inside the coax cable buried in the harness should compact or deteriorate where the cable turns a tight bend--presto-limp mode --the EGAS modules can no longer read the engine RPM from the ignition module (all the way on the other side, other end of the engine compartment) and so shut down as a safety measure. The MBZ electronic throttle is by far the least likely to have a 'runaway' or uncomanded acceleration type failure. Unfortunately, the converse is true--its the most likely to fail to work.

[JimF]

Originally Posted by Alans V12

Mercedes have had the car on their diagnostics and it says there is no reception from EFP N4/1 what ever that is. Alan

. . Menus 2, 9 and 24 for more info on the 'imfamous' ASR problem. N4/1 is the EA/CC/ISC module in my car; probably a little different in yours. This is part of the ASR system that MUST work. The N4/1 communicates via CAN bus, so a "wiring harness" could be the problem.

[LeaUK]

Thanks for the link to great example pictures of the wiring harness failure. There have been several articles pointing to this but this is the first real evidence I've seen - not that I'm a skeptic of course!

I'd love to examine a failed actuator (not a wiring harness failure), so if anyone wants to send me one I'll strip it and test to find exactly the cause - I guess it's the potentiometer but that's just my feeling.

Lea

[gmo442]

wow lots of great info..cant wait to look into my 600sl asr issue once the rain stops!