ABS ASR problems. - PeachParts Mercedes-Benz Forum

tower · #1 09-12-2004, 11:58 AM

Looking for everyone's help again. JimF has been most helpful in manufacturing a new EPROM for my DM 19 problem, I'm hoping that will fix that problem. But as usual, another hiccup has developed.

While on a 120mile trip, half way through my ABS & ASR light flare. I was just coming to a stop at a street light, where my right front tire started to slip in the debris along the edge of the road. I can feel the chatter under my brake pedal as the ABS system attempts to engage. About 1/2 second into the shudder, the ABS/ASR lights light up, the steering gets heavy and the vibrating brake petal (ABS) stops. This was about at the mid point of the trip. Suffice to say I continued along my way after stopping the vehicle and reseting the ABS/ASR. Everything fine. On the return leg, I attempt to turn left out of a parking space and the ABS/ASR fires up again. Reset and continue my trip back, almost in the exact same spot the system fires. Again making a left turn at a stop sign. From there it would fire off every 5miles or less.

Well I came home and extracted the error codes from the X11-4 for all the modules. There where tons of them. I can only figure that these are left overs so I proceeded to reset everything and do a little driving. When the ASR/ABS fired again, I read code 6 on pin 6, telling me "Left front axle solenoid valve". Might be getting some place but I need to do a check of the component before I rush off and purchase, so, How do I check this thing out?

As usual, any and all help is greatly appreciated.

Ron

Oh ya, its on the S420 (95)

teky · #2 09-12-2004, 01:01 PM

it seems you have a faulty abs speed sensor on that wheel, check the wiring and the condition of the teeth in the abs rotor they might be rusted or filled with dirt this causes the sensor to fail, some tips here
http://uk.msnusers.com/autodatabase/breaks.msnw

tower · #3 09-12-2004, 02:30 PM

Teky

First thanks for your reply, but, my error code (6) applies to the solenoid, not the sensor. Sensor I can check easy enough, but I have no idea how to check the solenoid!

Or am I reading you wrong?

Ron

stevebfl · #4 09-12-2004, 02:48 PM

Well, I thought I would look it up since I happened to be at work. We haven't had power at home since last Sunday. Just got it back last night.

I see a couple inconsistancies. The first is that I'm thinking a 95 might not talk using the impulse method. Second, there is a distinct difference in the 94 and the 95 wiring of the left front axle solenoid valve. The 94 just has a single valve but the 95 has two valves a hold and a release valve A7/3y6 and A7/3y7 (6 is the hold 7 is the release). The 94 model has only one valve A7/3y1. The code should specify as the two solenoids are separately controlled on the 95.

Ahhhh, I'm still looking and I just realised there are two Diganostic Manuals including ASR and in the second one there is an ASR for 140 after 06/94. I find that the code for impulse (must still work) #6 is Right Rear axle VSS (vehicle speed sensor). Now that makes more sense, given your symptoms.

Verify, but thats what I get DM Chassis and Drivetrain Vol 3 ASR, ETS, and SPS Models 129, 140 as of 06/94.

You can verify at www.startekinfo.com as the DMs are all there. The DM will explain the code and detail the electrical procedures for testing. In the case of wheel speed sensors it's usually the sensor, but then they are usually front sensors that go bad. They can be monitored for output. Its done best with a scope comparing two sensors at the same time.

tower · #5 09-12-2004, 05:23 PM

I am in the process of rehashing all that I have accumulated. I'm still hesitant to go the startech at this moment as the accumulated DTC's kind of scare me so, I will continue to drive and log everything down for the moment.

You see, originally when I queried the ABS/ASR Control module, all I got was a continuous half lite LED. Shorting the ground got the LED to illuminate more brightly but I didn't get any responses. I decided to clear everything out and then test again after a short road trip. Thats when I drew off 3 codes, 6,8,& 10 when polled. So today I again reset the codes and proceded to drive around just until the ABS/ASR light turned on. Pulled over and read the codes immediately resulting in code 6 only. I think I will continue this exercise for a short period of time and then inquire at startech.

Thanks for your help. I truly appreciate it.

Ron

tower · #6 09-15-2004, 07:59 PM

Well its involved a subscription with alldata and alot of testing, Teky you were indeed correct. Alldata confirms that error 6 of pin 6 is a right rear sensor. In the attempt to remove, attaching hex bolt broke and the original sensor could not be removed from its socket. Its amazing how much copper wire is wrapped up in the magnet of those things. Had to break the original sensor at the face of the hub (right word?), remove the core magnet and pry out all of the copper windings. Took a little time. The worst was breaking 2 twist drill bits (able to remove successfully intact), one easy out and the multiple cable supports. Man was that thing rusted in.

Anyways.....done. Works beautifully again.