If I had any money to bet I would say that moisture got into an electrical connector causing your issue.

Anyone who tells you there's no codes when the ASR light is on is just trying to get rid of you - having made the moral decision that cheating you is just too much trouble. You should take this as a sign that it was the wrong place to take the car in the first place.

With my 2 year old problem I'm following this thread with interest. I throw the same code consistently but I complicate the solution by NOT getting any warning lights (no ASR or Check Engine) After 2 years it is more a battle of wits than a serious problem.
Someone mentioned a "sticky". I have had advice from MB Doc, Steve Brotherton and the Renntech guy. All agree it is an electrical problem, but where?

Anziani

common cause is fault code N4/1 no canbus communication, so far no one in the whole world has ever come up with an exact science on how to resolve the issue, all guesses (better than nothing i should say) but so far no one has ever sincerely reported their problem to be resolved, if you must consider changing everything then that is not resolving the issue prudently. the usual culprit which sets off this ASR issue are the bad wiring harness on the ETA and the engine harness, it somehow destroys the ASR Control Module (located inside your black box).

Still hoping someone may enlighten us victims of ASR nightmare with a true blue resolution and finally putting to rest this 15 year old problem.

The "canbus" . . . actually it's CAN bus . . . error code is just a symptom of failing w/h or a going-bad ETA or failing brake switch or NSS. Those are the main culprits. The CAN itself does not fail just the inability of the ECUs on the bus to communicate.

I've personally NEVER seen a bad ASR module as a result of a going-bad ETA, w/h or anything else and I've seen a lot of them.

My ETA writeup is the BEST overall treatise on the problem b/c it shows initial symptoms plus DTCs, then, as it progresses, variations on these symptoms and codes, then finally what happens when the ETA dies.

Also later in the writeup (about 2yrs down the road) the DTCs and LH problems return but now, it's another module, the NSS.

The reason that "no one has come up with an exact science . . . " is simply that there isn't any method including MB's Star system that can diagnose which part in the chain is bad.

This is a common problem in ALL electronic system where there are electronic elements (ECUs) in series. Any one of them can cause a problem and it's impossible to diagnose if there are no intermediate TEST-POINTS. That's the main problem with Mercedes' fly-by-wire system.

When Mercedes built these cars, the concept of adding TPs was in it's infancy. Nobody thought about adding this important feature. Now it's the norm. Had some TPs been used and brought to a test connector, the problem would have become trivial.

But however trivial it might have become, the "FIX" would still be expensive!! :mad:

As I mentioned this is an intermittend problem, and when i took the car to have the codes scanned, the asr light was off. I tought there would be stored codes from previous times when the light came on

When I collected the car from the dealer yesterday, I spoke to the foreman that was working on my car. Obviously he found no error codes. He told me that he open and dried most of the electrical connectors that pertains to the asr, and made sure all contacts are in good order.

I drove another 500miles and no asr warning yet. Started up this morning and drove 70 miles no asr warning yet:)

we will see what develops over the next few days!

I am of the opinion that miosture or a bad connection was to blame, anyways I appreciate all the help and advice I recieved here. I will post a follow up.

For now I am going fishing!!

There would have been.

Peet,
I hope that your problem is solved. I live in the desert and I don't remember the last time the car got wet and since it is a '93 300CE the error codes are a lot simpler. Yes, the wiring harness is good. The ETA and harness are new, and yes, I may never find out what is causing this once a day occurrence. :(
Anziani

Update
 

Drove the car again today, still no asr light:):) Perhaps I am one of the lucky few that just had a bad connection somewhere or some moisture that dried out.

One thing is for certain, I will not ever presure wash the engine and chassis again!!

Newer than mine ...
 

Yours is a later car so what I'm going to say is probably even more relevant.

Whenever you see an electrical connector, clean it. Use a good quality contact cleaner (not WD40, in my opinion) and disconnect/reconnect several times to clean the contacts. Do this every time you find a plug/socket you've never seen before.

Cost - almost zero.

Time - very little.

Risk - low.

Benefits - potentially great and more so with more modern vehicles.

Just don't break anything and if you do, repair it properly.

RayH

Desperation
 

Ok so after the car came back from the dealer, I drove it for about 4 days without any incident. Then the intermittend asr light came back, would cancel and reset after switching the ignition off and re starting would stay of between 3-5 days then without warning I would get a asr warning light.

On saterday while taking a drive to the drugstore asr turn on, but after the restart turned on again, did this 5-6 times, so no it seemed that simply restarting would not cancel the asr fault.

so when i got home I decided to trace the ETA wires, wires sare in good condition, did notice that the manuffacture date on the VDO ETA was 2002 stamped in blue on the ETA casing(car is a 96) thus the ETA must have been replaced by PO right?

Then i removed the plug from ETA to wiring harness and cleaned this connection with electrical contact cleaner.

I then removed the ASR module from the bin and cleaned both rows of contactors with the cleaner inspected the wiring at the bottom where the module plugs in, perfect.

then removed base module cleaned contacts checked fuses on base module by removing and replacing them.

Then cleaned the connectors on the wheel speed sensors.

started the car up asr was off then proceeded to drive about 100m in pouring rain, and yesterday about 120m in hot conditions, drove it into work this morning and asr lighjt never came on.

I am holding thumbs that I had a bad connection somewhere.

just as an after thought I know that on USA models and probably on euro models you can jump pin 1 and 6 to put the asr in diagnostics mode which will eliminate limp home mode but will not turn off the asr lamp, BUT on my model South African version Pin 6 in the 38 pin socket is a dummy??

is there a jump that would put our Southj African models in diagnostics mode??

ASR on again
 

Well today after 4 days of trouble free driving ASR came on again out of the blue. Switch of restart ASR light went off and stayed off.

I will no be replaceing in the following order, Brake light switch, then if no Nuetral safety switch, and lastly I must look at the ETA(that was replaced some time ago)

Is there any other components I might have overlooked?

peet230,
I feel your pain. There are 4 wheel speed sensors in the circuit. I pulled each and cleaned them. No improvement. If you send me your email address i will send you my 2 year history of what I have done. :(
My address is <anziani14@dc.rr.com>
Anziani

Have you cleaned your ETA? Here's a good throttle cleaning kit from Amazon.

3M 08963 Fuel System Tune-Up Kit

If that does not fix it replace your ETA. That's the fix for ASR problems most of the time.