Need help! Weird ASR problem!!

[spinedoc]

1996 SL500 Iam getting a very weird ASR problem. Sometimes, and it seems to be associated more with after I turn, the ASR on my car starts blinking and I get the throttle reduction. As long as I keep my foot on the gas, accelerate or not, the ASR light keeps blinking and the throttle stays down. I'm not sure if its when I take my foot off the gas, or if its when I put it on the brake, but then it stops blinking and mycar goes back to normal. It is very sporadic, maybe 1-2 times per week, so I dont think I want to spend the money at the mechanic until I can pin it down a bit more.

Keep in mind that the ASR light is not going on completely as in the "limp home" mode. It is blinking like the tires are slipping, but it keeps blinking and engaging while I have the gas pressed. I am most definitely not slipping as this has happened with me going at very very low speeds. I have held this blinking pattern by keeping my foot on the gas for a good 2-3 minutes.

Help!!

[spinedoc]

OK this morning it happened and I didnt have to press the brakes to have the ASR go off, I just took my foot off the accelerator. But as long as I kept the accelerator pressed, a little or a lot it did not matter, the ASR light kept on flashing and the throttle was cut back.

[spinedoc]

By the way, to clarify, the ASR light itself NEVER goes on, just the exclamation point light in the dash. It's like the ASR function gets "stuck" on, but no fault codes are generated.

[spinedoc]

Any ideas?

[jnelson]

I am having the same EXACT problem you are describing. I usually notice the problem more frequently once the vehicle has been sitting for a while and is cool. Once it warms up and has been on the road a few miles it rarely happens. No codes in the CEL, No ASR light. I ohmed out all of the speed sensors first. Front two are at 1.65, 1.66 KO. Rear two were off just a shade from each other, 1.62, 1.55 KO, but wouldn't seem far enough out of range to cause a problem. To me it still definitely points to a speed sensor problem. I think we have a stand alone year as well, early 1996 129.067, straight ASR without ESP. No yaw rate or lateral acceleration sensors.. Not sure if the later M119 engines had problems with the throttle bodies or throttle position sensors. Just wondering if you ever got anywhere with your problem?

[Will_w202]

Check anything voltage related. These things will turn off secondary systems (srs, asr, etc) if voltage is low. Obviously voltage would be lower when cold. As in battery

[jnelson]

You have a good point... I would have looked there next. I did end up fixing the problem. Here is what I found... 3 of the 4 tires were the correct size at 225/60R16 and the 4th was a 225/55R16. I replaced the incorrect tire and that fixed 75% of the issue, however the problem persisted under engine load while cornering. Replaced both rear wheel speed sensors as they were original and slightly out of spec. Did not need to replace the front two speed sensors as they had been replaced at one point in time and ohmed perfectly. I did however clean them. All in all it was a combination of two problems. Mismatched tires and worn/dirty speed sensors. Just thought I would post my findings. JNelson