ABS light ON/OFF!!?? PICS OF THE GUTS!!

[Dino]

OK OK OK OK!!!!!

I love it when I do stuff like this....

This is what your ABS unit looks like with the control unit removed. Each one of the dowel like projections is a valve that can be operated by a winding of wire with electricity applied thus creating an electromagnet and opening the valve.





This is what it looks like when you pull out those torx screws...



This is the ABS control unit. The side exposed is what fits over the valve block. Each cylindrical part you see is a coil of wire that gets electrified when the ABS is triggered. The resulting electromagnetic force makes the valve open.

THE REST OF THE STORY...

OK. Like many, I've been driving around with the ABS light on. No biggie really in my opinion. I thought I'll fix it sometime..

Well, about a week ago, after that discussion about possible stuck valves and such. I decided, what the hoohaa! Let's bang on the valve block with a ball peen hammer. Just a few "smart" raps here and there oughtta do it!!

Nothing. Light still on.


But.. a few days later, during wet weather, I hit the brakes on a corner where I met a truck coming and I felt, brruururup! in the brake pedal! I looked down and NO ABS light!! WOW! OK cool. I figured I'd test it so a bit further down the road I hit the brakes with one front wheel off on the dirt shoulder and it worked again!

I drove another few miles, wondering, no, ... racking my brain to think, think, what made it do that?? Alas, the light came back on a few miles later. But it got me to thinking about all this ABS stuff so I read up on it in the manual and such. Not much news there except to check the connectors under the car. I pulled the rear sensor connector for each and then pluged them back in. They loked fine. I checked the fronts the same way. I checked the connector at the control unit, again...

Then I said, screw it. I'm going exploring!

...and so, I pulled the unit apart and put it back together, but not before I got pics for all you curious ones like myself. Let me tell you, that thing is near bulletproof! It's some kind of phenolic material. You can't take it apart without smashing it!! Too bad...

TODAY... my ABS light went out on the way home from work!!
Nice warm sunny day. I checked it a few times on the dirt road. Working fine. Shut down the car when I got home, restarted, still working.

For how long though.. and why!!?????????????


AAAAAHHGHGHGHHGHGHGHGGG!!!

[ZEUS]

That's so funny Dino! I am the same way - sometimes I even put things back together correctly! Thanks for the pics.

[johnnyapollo]

When mine went out I started a couple of email dialogs with various unit rebuild shops - they all consistently said that this particular unit could not be rebuilt and even admitted to trying different things on occasion. Seems that Bosch wanted to make sure that this one was unrebuildable and used materials that would prevent it from being so - your observations reinforce that statement.

Since the light comes on for various reasons, fed back by sensors, it could be that you are very close to the tolerances that cause the error - meaning that if the sensor is detecting a change in amperage (or whatever it's checking for, fluid pressure, etc), your unit might be on the verge - over time it slips back into acceptable range so the light goes off - just a theory.

The check lights tend to reset after x number or restarts (I believe it's 30) as it only keeps x number of rows of information - eventually the oldest code drops off, so at some point your light would go off anyway, then come back on when the sensors detect the problem again.

-- John

[VehiGAZ]

I think it just wanted some love and attention. It's been ignored for so long...

[Dino]

I drove it about 15 miles last night and it stayed on the whole time.

[Dino]

The ABS started working again this afternoon.

I was on the way home, AC on nice and cold, and after about ten minutes of uphill highway driving, the light went out and I had ABS again.
When I got to my dirt road, I hit the brakes hard enough to activate it and repeated this about a dozen times!!! I got home and parked it, shut down, wait a minute, restart and it was still OK.

Just now went out and started it up, two hours later, ABS light on. hmmmmm

The only sensor in the cabin is the G-sensor. Maybe I'll pull up the console and have a look tomorrow.

The troubleshooting continues...

[etlsport]

ever since the weather turned cold my abs light turns off after the vx sits for 3-4 hours... overnight temps got to 50.. went to start it.. abs light was on all day... today it was snowing.. no abs light... nailed the brakes on a back road.. they kicked in no problem... happened a couple more times.. few more miles down the road the light came on again... hit the brakes and slid around a bit... oh well who knows what causes it.. guess maybe now ill put the new module in