ASR Warning Came On ... Now What
 

:confused: I was driving home from dinner last night ... and after completing a right turn at normal speeds ... the ASR warning message splashed across the instrument panel message area. The engine continued to run at nominal idle, however I could not throttle up the engine and there was no propulsion to the rear wheels. I pulled over to the extreme right apron of the road, out of the way of traffic, and turned the engine off ... waited about 30 seconds and restarted the engine. The ASR light did not come back on ... I drove about 4 miles to home without incident.

Are there any suggestions as to how I should proceed to diagnose, correct, remedy the problem? I have to use this car to ferry my 86 year old mother back and forth across Alligator Alley and I can't afford to have it break down on that desolate road with an old lady in the car.

I've got a 1996 E320, with 57,000 miles on the odo. I bought the car new and my maintenance has been and continues to be impeccable and beyond that which is called for in the owners manual by MB. The only other thing that has required action beyond preventive maintenance is a CEL light of P170 which appeared two weeks hence, which I tracked down to a "potential" MAF failure. I removed the MAF, cleaned the sensor plate with a non-residue/high quality electronic component spray cleaner and dried it with compressed air. I cleared the CEL code and replaced the MAF ... and the CEL has not come back on (yet).

I would appreciate any and all assistance. Thank you.

Sure does sound like a bad throttle motor to me, I suppose it could be the microswitch in the gas padal too, but probably the throttle motor.
Need to check for stored codes in the ECU and ASR
Gilly

<<and after completing a right turn at normal speeds ... the ASR warning message splashed across the instrument panel>>

Check tire pressure/size for uniformity...

Arthur, I thought of that too, or maybe a wheel speed sensor, but I don't think these faults would cause limp-home mode.
Gilly

I thought of that too, but b/c it is in a turn , it may trigger limp.
Just a first check I would do........if for no othger reason than to get it out of the diagnosis.

Sure, makes sense to check it, or maybe a case where the owner just rotated tires or had to replace a single tire for some reason, or put the spare on it. Best course right now, besides the few things we've mentioned, is to get it checked for codes.
Gilly

I agree.. that is why I mentioned tire size along with air pressure.
Codes are next step and would not be surprized to see a brake lamp sw fualt in the codes memory .......

hmmmm ... will do ... right away. thank you much.

No spare on it ... just normal tires/wheels. Will check air in all ... then put my OBDII code reader on it ... may have to get back to the forum tomorrow .. chaos in my house today .. :silly: my wife is home ... honey do this and honey do that ... :( I'll see what I get from my code reader and report back to the formum ASAP. thanks you guys.

:confused: Is there another term for "throttle motor." This is an "old" straight six 104 engine ... not a "throttle-by-wire" like the new ones. Pardon my ignorance if I don't understand the terminology. Would appreciate any additional info on the "throttle motor" and its location. I am assuming the m/switch is in the vicinity of the gas/throttle pedal. However, I realize that I need to draw the codes out of the car ... or try to first. thank you.

Thank you for telling me about "limp home" mode. I didn't seem to be able to crawl anywhere, much less limp, when the ASR warning splashed across the visual annunciator ... is there something special one does to "limp" home? My recollection was that I applied pressure to the gas pedal and there was zero forward response ... almost as if the throttle and transmission were completely disengaged ... but with the engine at nominal idle ... ok ... I have to pull the codes ... or try to. thank you.

Update ... More Information as Requested
 

Gentlemen ... after I went AWOL from my Commanding Officer (Wife) ....

I checked the air in all the cold tires ... they were all down 3 psi uniformly. I filled them all to factory cold air pressures.

I hooked up my code reader ... and there are no codes stored in the ECU. I hooked up twice and restarted the engine just to make sure there were no connection glitches. The code reader went through its diagnostic thing and did everything it is supposed to do ... but there were no codes to read.

I'm left perplexed ... and concerned about the reliability of this great car ... heretofore it has been Mr. Reliable ... any more ideas?

I would still suspect brake lamp switch.. very common and this is one of those "Change it" recommendations as it takes longer to catch it faulting than it does to change it. [ cheap part] One of the few times I will try a new as part of diagnosis [ the other being an OVP relay]

..do a search and be sure to use OEM sw.
What happens with the codes is they will clear themselves after so many no faults , so an intermittant problem like a set of sw contacts can show as a no codes and still be the fault.............depending on when you go checking.
If the asr comes up again , immediately code check

Yes the car certainly IS throttle by wire. The throttle motor is the part the "wires" are controlling. Located on the intake manifold.
Gilly

Oh btw yes there are numerous names for the part such as the throttle actuator being most common I think, also something in the parts literature referring to a "slide", and also references to E-Gas. Alway been the throttle motor to me, has a rather large electric motor that opens the throttle plate/butterfly.
Gilly

I'm sorry ... I must be getting old (I am old) ... I remember hooking up a cable from the gas pedal to the AMG engine throttle body I pulled out of a wrecked C36 when I stuffed it into a black market E190 16V ... about 7-8 years ago. I don't recall a "throttle motor" on the '95 C36 intake manifold ... MB must have gone to throttle-by-wire in 1996. However, my memory is so damn foggy. I have never really had to fool with my E320 ... so I assumed it was a cable actuated throttle body. ... sorry. I'll price the throttle motor and see about RR it.

Brake Light RR ... where is the Switch Located?
 

Ok ... will certainly keep the code reader in the car ... and if the ASR fault message comes on again ... I'll immediately read the code before "rebooting" the car. I'll go ahead and order the brake light switch now ... can you tell me about where it is located so I can start looking for it? If it is too much of a contortion for my decrepit old body I'll have to ask a young guy I know to wrench it for me. Thanks.

Oh No! Say it Ain't So!!!!!!!!!!!!!!!
 

:eek: Holy Hanna! Now I am confused and decidedly upset!:dizzy2:

Take a look at this: http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1W810D47Z1W81419W4&year=1996&make=MB&model=E-320-002&category=C&part=Throttle+Actuator

When I went to look for the "throttle actuator" it says: "Note: Not for models with ARS <must be a typographical error and it must mean ASR> Cruise control actuator only for models without ASR." And the thing costs $1514.70! :behead:

Now does this mean this part does not fit on my engine? And, if this is not the throttle body actuator for my 96 E320 ... where do I go to find one? I sent an email to Phil ...maybe he knows. And how can I be more certain this is the mother that is causing my ASR fault? Man, this is one heck of a big purchase just to try and see if this is the problem...

I ordered the brake light switch ... $23 shipped to my house ... I can handle that ... that's a throwaway price .. but $1500! Oh man ... I'm retired ...
Maybe we can start up a collection (LOL) ... :wacko:

You're in luck the throttle actuator for ASR models is actually cheaper than the one without ASR - one of the few breaks bestowed upon ASR owners. And you may not want to get a new one anyone - rebuilts units are available. But before you do that you should eliminate all other (cheaper) possibilities.

Other things that might turn on the ASR light ...
 

You betcha ... I wish the local dealer was worth a darn here ... but its not. My old dealer in Virginia was super ... even lent his bays out and had technicians around on Sundays for MB Club Members ... here in Sarasota you never know what you are going to get from the dealership. I know an old crumudgeon German guy that owns a strickly-MB shop ... I'll take the thing to him and see what he says ...

:idea2: Does anyone out there have any cheaper possibilities or ideas that can lead me to the culprit turning on the ASR fault message and making the car go into limp home mode? I've put air in the tires and I am replacing the brake light switch. So far only $23 in the hole ...

If I didn't have to cross Aligator Alley with a couple of old ancient ladies in the car I would just see what happens ... but I need to be pro-active. If I break down in the Alley this time of year in this heat ... it'll be tough on my mother and sister. Anyhoo ... guess I need to chase this down some ... :book:

Thanks for all the help so far ... c

Try a search. It seems to me it can be something as simple as a floor mat restricting the gas pedal, or throttle linkage out of adjustment, or a dirty throttle actuator, or bad throttle actuator wiring. They do go bad but it's also a common misdiagnosis. My parts supplier told me that he gets a lot of followup phone calls saying the new throttle actuator didn't solve the problem and at those prices a lot of people want to return.

Ok, thanks. I keep wondering if I'm not focusing on the wrong end of things. After all the ASR is all about traction control. Perhaps its because of the way I framed the question and the information I provided about the throttle. The crux of the problem is the fact that the ASR fault message came on and the car would not respond to the gas pedal although the engine was on and at idle. Something had to make that ASR system fault. Like the gentleman said earlier on .... check the tire pressure ... which I did and I had to add air to get the pressure up to snuff. I think what I'll have to do is simply wait for the incident to happen again and then see what codes are tripped ... before I "reboot" the car ... again following an earlier recommendation. Simply replacing the TA on a hunch is just too expensive a proposition. And, if it get down to that ... believe me .. I'll be hunting down a used TA. In the meantime ... I might have a full-time MB mechanic take a shot at a diagnosis ... then consider his suggestion. Again, if it weren't for the need for a reliable set of crossings to get from the west coast of Florida to the east coast ... I would just wait it out ... or maybe even ignore the problem. Again, thanks to everyone for their thoughts and recommendations.

C

ASR light on
 

I have read and learned a bit on this website. I think that I should share my expensive experience with you guys.
My car is 94 S420, I have exactly the same problem as you describe... the engine is on but no power to the transmission, ASR light lit up, turn off the engine and start normally as it never happens. This happens just once in a while, it only happens when I apply brake especially when it rains. I bring my car to change a harness... it costs me CAN $1300.00... Just seconds after I leave the shop.... it happens exactly the same... Holly cow... So... I change the brake light switch ($25.)... And ... the problem is solved. I believe that this switch is not only light up the brake light and release the shift gear solenoid but also send the signal to the computer to dis-engage the engine from the transmission. To test this, I put my car on Drive gear, one foot on the brake and the other on the gas pedal, the car does not force to go forward. which means that when I apply brake, the engine and transmission is actually dis-engaged.
I hope that this helps and makes sense to you

Cars I had
1991 560SEL
1994 S420