Alright. I want a ASR defeat switch like the one precision sells for my W210 E320. I was going down a 4 lane road the other day driving along, minding my own business when suddenly mt car shifts down, RPMs hit about 6000, and my rear end comes completly out from under me and I land in the ditch. I was going about 40, with just my left (nondominant) hand on the wheel, so I had no chance to recover. Only a small scratch to the driver's side front spoiler and a bent foglight. ASR works great in the snow, but I want to have control of my gas and brakes! I guess I am just a little to demanding Anyway, anybody know where I can get an ASR defeat switch (not chip) so I can turn it on and off as needed? Thx

I can not imagine your symtoms being caused by an ASR problem.

Sounds to me like a transmission control problem, maybe caused by a selector switch problem.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

The local MB dealership said there may be a bad rear wheel sensor or something. He said the car thought it was doing the right thing but in all reality it (obviously) wasn't. H said the car shifted down so it could gain more torque and regain traction...

I hate to be cynical, but, that sounds like a service writer talking to me.

I have never heard of a strategy involving transmission downshifts to gain traction. It plain don't make sense. Besides, a speed sensor problem would absolutely set a code.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

Actually, the idea did sound a little crazy to me. Do you have any ideas as to what have gone wrong?

Not to doubt Steve's wisdom whatsoever (correct me if I'm off on any of these points Steve...) but I've encountered a few situations where ASR has made a oversteering slide MUCH worse if the slide gets going before ASR catches things. Could be reads the slippage, cuts throttle, applies brakes in an attempt to slow the spinning wheels but since the oversteer is already going this does the infamous "yank the handbrake" move by throwing polar intertia to the front (hence reducing traction at the rear). Physics, electronics, etc aside it tends to make the car "wag" for quite some time before regaining its senses. (far more than just a regular oversteer slide)

ASR seems to stop any chance of power induced oversteer 99.9% of the time but occasionally (or when/if) a tail-slide gets going (for whatever reason)....look out it can be more than a handful as it doesn't behave as you'd expect a normal car to. Forgiving is the last term that springs to mind.

As for why your tranny behaved the way it did, I'll leave that to the wisdom of Benzmac and Brotherton. My only question there is what was your throttle position activity for the few seconds/mins prior?

I'm glad you and your car are generally okay. Only thing is...would you of had time to hit the ASR defeat switch soon enough to effect the outcome? If you are planning on gasing it around it will most certainly help (autocross, drags, empty parking lot, etc) In normal driving (ASR "safety net" engaged) the action of ASR would be my primary concern. In my experience MB ASR'd vehicles don't behave as you would expect from a traditional rwd vehicle at the limit. Some time in an empty parking lot with some cones and/or a driving course could go a long way to getting used to how the car behaves at 9/10ths to 11/10ths. Before doing any of that I'd want to make sure everything in the car was running as it was supposed to.

Glad you are okay...Lee

before the slide, I was driving at about 40, and nothing funny was happening. The ASR light on the dash started blinking at a constant rate and it all went to hell from there. The car doesn't respond like I'm used to (Corvette) when pushing it. I had a 93 300E with ASR and they both don't function quite the same.