ASR problem Can't believe this. Please help.

[Alans V12]

I have a 600SL 1995 which was running perfectly ok. I then discovered that I was leaking water from the radiator as the warning light came on. I wanted to see where the leak was, so I opened the bonnet to have a look. At the time it was not obvious but I could see some signs of water leaking probably under pressure. I then thought I would rev the engine to see if I could see where the leak was. To do this I manually turned the thottle cable as one normally would to rev the engine. I found the leak. I went back into the car and found that my ASR light was on. I thought nothing of it and went to drive the car. The car had no power. I turned the car off and on and the light went out. A few hundred yards down the road the light came back on again. I checked the handbook and it gave various reasons which were not related. The problem would not go away so I have taken the car to a main dealer who have run diagnostics on the car and they have said that the readout shows no reply from the ESP Electronic Throttle pedal control unit which is the ASR light. They tell me that I need a new one which will cost fitted nearly £2,500. I cannot believe this can be because of what I did by just reving the car. I have had this confirmed by another garage. Sometimes the car is ok and runs fine for a bit and some times the light comes on straight away.

Can anyone out there help or give some reason or if this unit can be repaired or even if it may be something else as I do not want to spend this sort of money which may not cure the problem.

Thank you.

[190]

I don?t know about the 600sl but on the Vauxhall Vectra I have seen this light coming on and if you disconnect the battery for about an hour and reconnect 9 out of 10 times it resets it?s self, I would give it a try you have nothing to lose JUST REMEMBER YOU WILL LOSE THE CODE FOR THE RADIO make sure everything is turned off before disconnecting an reconnecting the battery hope this works for you.

[guydewdney]

this is a known issue - never never rev the engine using the sensor in the engine bay - it gets the coimputer all confused.


i belive it is fixable without buying anything - but its a re set of a lot of stuff...

get a decent man on the end of the laptop to sort it.

[Alans V12]

Thanks, I have already tried disconnecting thje battery with no joy. Does anyone know someone who may be able to re-configure the unit.

[Warren Stevenson]

Hi Alan,
I have my own business in Perth Western Australia and have encountered my own experiences with a W140 S600.
As for dealerships, well forget them - the cars are so infrequent that tech's just don't have a clue.
My experience started also with a coolant leak - I found that when the ASR light comes on, the "slave" throttle motor on the non-cable side of the engine stops working - hence lack of power. Stop and restart and ok, but no logged codes.
I know that since you have taken your car to the dealer, they may of played with it and adjusted components that did not need adjusting.

1st). On the passengers side (I take it it is R/H/D), check to make sure the throttle cable is adjusted correctly - you'll see a little marker on the throttle body and by screwing the throttle cable in or out until it is aligned with the pointer - I can E-mail pictures if needed.

2nd) Under the same side throttle body should be a return spring - very fine type that can fly off and not allow the potentiometer to return to it's base position. If this is the case, any small type of extention spring will do.

If the spring falls or breaks off, the 2 throttle bodies will lose synch with each other and bring on the light, cause lack of power, but not flag any codes.

On an SL, you will need to take off the induction pipe and use mirrors to check for the spring.

I found that no-one knows anything about these cars and simply would replace the throttle body or ASR control unit and give you a HUGE bill.

I have some tech info somewhere in my files, but hope this gives you some direction.

GOOD LUCK,

Warren Rare Merc lover :D

[Alans V12]

I am still having trouble with my ASR. I have tried all of the above with no joy. The other day I started the car and the light was not on. I took the car out for a long drive and it was fine. I couldn't believe it. The next day was also fine with no trouble. I thought the problem had gone away. The following day was different, the light is back on the car will not do more than 30mph. I still can't believe that I need a new Electronic thottle pedal control unit (£2,500) it is either not working or it is. It must be some kind of adjustment somewhere.

Anyone out there know of anymore.

Thank you in anticipation.

[mjtray]

Suggestion: try posting the same query on Mercedesshop.com....they have an excellent forum which is visited by loads of Technicians and being an American site they probably have more experience of v12's than we do here in the UK

Here's the link http://www.mercedesshop.com/shopforum/index.php3

Good luck and let us know if you get it resolved.

[Arnie]

Are you sure that the ASR light is really connected to what you fiddled within the engine. It may be just a coincidence?

The ASR, as you probably know is the Acceleration Skid Control (traction-control), and while it is linked to the engine via the engine control unit (retards engine ignition to momentarily reduce power), I don't think that it has any direct link to the the electronic throttle actuators.

However, a faulty accelerator potentiometer, may give a wrong input to the ECU, but this potentiometer is not £2500, more like £300.

I mention this because there are other known causes for the ASR light to come on and maybe you should check these too.

Anyway: see here:

http://pages.prodigy.net/jforgione/MB_asr.html

[mjtray]

Just read the link out of interest.....he seems to know his stuff!!! :shock:

[Alans V12]

Hi everyone me again. Thanks for all your help but the problem is still there. There is no pattern to when the ASR comes on. I drove 100 miles the other day and it was fine. Now it's back on again. It's awful, I have no confindence with the car and can't risk taking it anywhere.

I have been told that the ASR can be turned off and there is a company called RENNtech who sell a component which is easy to fit which turns off the ASR. They call it a ASR DEFEAT SWITCH. Has anyone heard of this and will it work on my model. Also does anyone have a contact for them.

Thank you.

[guydewdney]

tip - where are you based? It muight help people sugest a decent techie to help you fix this.

two of the best are andy gale in birmingham and george fraser in west london.

[Arnie]

Alan,

Did you read this link?
http://pages.prodigy.net/jforgione/MB_asr.html

There is information on how to diagnose the throttle body and from what you have written this may be your problem.

It also mentions how to disable the ASR function quite simply.

[Alans V12]

Thanks guys

I have read the link from jforgione, interesting. I have cleaned the ETA's they were filthy but still no joy. The last few days I have noticed that the ASR has been coming on when the engine is cold, once running for a while, I will turn the engine off and start again and the car will be fine no ASR. After reading jforgione link it may be that I have a faulty ETA. Are they difficult to fit. I think it is the side of the throttle as I have noticed a burning smell there when the engine gets hot. I have been told it may be the potentiometer also. Is this part of the ETA or something different. If it is different where is it. I live in Tunbridge Wells, so it might be useful to speak to the guy you suggested George Fraser in London, do you have his phone number please. Sorry for all the questions but I want to get to the bottom of this. I am learning alot.

Thank you.

Alan.

[guydewdney]

gf is on 02087951055 - be prepared to wait - hes a busy man..

you can tell him i sent you (he did me a favour, so im sending customers to him ;) )

[Arnie]

It seems that the potentiometers inside the ETA, which give the throttle position feedback to the car's ECU are prone to wear and failure from high temperatures. If cleaning the potentiometer tracks does not fix the problem (because they are worn), then you will need a new ETA, althought the link-article ends by saying that there is now one company in the US which can repair them (maybe they can send you an exchange unit?).

Also, your troubles did seem to start when you manually moved the throttle assemble and possibly disturbed a faulty potentiometer inside the unit.

[guydewdney]

i know its a 600 and this is off a 300 - but the throttle pot might well be the same ..
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=10398&item=4506669 036&rd=1

[Alans V12]

Thanks arnie, It is starting to make sence now, you may be right, looks like I will have to take out the ETA's to check the Poteniometers. My main dealer want's £1,700 each for a new ETA. Hopefully it will just clean up. I will you know what happened.
Alan.

[Alans V12]

Hi All,

After months of frustration my ASR problem has been sorted so I thought I would let everyone concerned know. Four garages looked at the problem and each one said it was the ASR control unit ( £2,500) I did not believe them after reading all the information sent to me on this web site. George Frazer Mercedes in London was the last garage to look at my car. He had the car for 2 months and could not sort it. He admitted that it had beaten him and I was due to pick the car up the following day without the problem solved. He said to me that he had one last look at it the night before I was due to pick the car up and he found that the wiring loom from the Actuator was completely burnt out and all the wires were touching setting off the ASR and putting the car into limp home mode. The wires had perished. 2 hours labour was all it cost. I was so happy as you can imagine. He told me that my car was the worst he had come across and that he had learnt a great deal from it. I know that a main dealer would have replaced the ASR control box and it would not have cured the problem. God knows what sort of bill I would have eventually had.

I hope this may help other people who have a similar problem.

Alan.

[davidsl500]

Thanks for the feedback Alan and congrats to getting the problem sorted with your wallet left intact!

Just shows that its best to check absolutely everything before forking out loadsamoney and also proves that the independant merc specialist rules on these slightly older vehicles. Looks like Mr Frazer made some more brownie points.

[Vangogh]

I have heard that you can buy a defeat module to overcome the rev limiter on performance cars. It might be from Demon Tweeks, they may be able to help.
Good Luck
Vangogh
SLK 230
C180

[jberks]

Congrats on getting it resolved. It shows once again that the indies are the only way to go with obscure faults. They take failure personally and generally won't give up - I guess its their professional pride not to mention reputation. - something the dealers seem less concerned by.

Dealers only seem to go on what the computer tells them. Having had a dealer tell me (in my case) 'the computer says there's nothing wrong' I followed the same route as you. 3 days with the local specialist and I too have a car I'm very happy with.

[R129]

A good lesson to be learned here I think.

Another case of the professionals automatically assuming the most complex component must be at fault and neglecting the simpler possibilities.

This is the sort of fault that an old school mechanic would have picked up quite quickly as no doubt they would have started off with the basics such as checking fuses and supply of power to the modules which would probably have shown up the fault quite quickly.

Learn this lesson the hard way myself after 3 months and £2000 (which I did'nt pay) at a dealer to cure an ignition fault which turned out to be carbon tracking in the distributor cap.

[Sugarboyjoe]

Hi there

I have a very similar problem - I have a 1994 SL600 which has an intermittant ASR fault.

The diagnosis was with a faulty throttle body. These item were originally wired with biodegradable material and they eventually end up failing.

There is a website in the USA which details how to do this excercise yourself if your up to it - I'll email it if anyone is interested.

I got my throttle bodies done - but it looks like they have been incorrectly wired - I am now desperate to find the wiring diagrams.

If anyone knows where to obtain - I would very much appreciate the info ( would even pay!)

Joe

[Parrot of Doom]

Is the original manufacturer (not MB) name stamped on the throttle body anywhere?

[kth286]

I never saw this post in the past but I do know the following:

On ASR equipped cars do not pull on the throttle cable to raise the engine speed for any reason. If the engine speed for any reason increases via the throttle cable without the corresponding indication from the throttle pedal position indicator it will set a fault code, the check engine light will illuminate and the engine management system will place itself into limp-home mode.

The fault code will have to be cleared with the hand held tester or the STAR laptop.

End

[Brookspeed]

Alan,

I've had exactly the same problem with my 1992 600SEL. First the radiator went, which I had changed at Mercedes-Benz. Then the ASR fault developed. I was in the south of france at the time and a dealer there ran diagnostics to find a faulty wiring loom. I replaced this myself and the problem cured for a few days and the returned. I've been told the same as you by my dealer and have currently been investigating breaking parts from Mercedes Benz Enthusiast