SES + TRIFECTA LITES = Vacuum leak?

[Bmwtvboy]

So, recently got a code for big vacuum leak. Possible cat failure. Then got the classic trifecta lights. Noticing a very slight rumble from left front wheel.
Can a worn wheel bearing trigger issues with the brake/speed sensor on the left front wheel? If the SAP hose lines are 16 years old, and seriously cracked I can figure they need replacing . BUT what about the electronic vacuum control valve? Do these fail after all these years? Is there some test? I see there is another valve before I get to the brake booster. This one too?
X drives fine, good mpg and braking is strong. Any advice or experience
wtih this side of issues?

[Ricky Bobby]

Is the rumble above 40? If not its not a wheel bearing, they make a horrible howling above 40 (think WWII Bomber drone)

Replace all the vacuum line and tubing from the SAP to the back of the intake manifold, and the 2 vacuum caps back there, as well as the 2 short sections of hose between the check valve on the back as well - I also replaced both pieces that come off the "L" fitting on the lower intake elbow recently, lower intake elbow itself was replaced a couple years ago.

If you still have a vacuum leak after all that, I'd be shocked.

[Bmwtvboy]

No it's not that loud, it's just a rumble under the left foot rest , guess it could be the tires.
I am ordering the vacuum line, pipe and back flow pressure valve to the brake booster.
My intake elbow is great. No one seems to sell the sap vaclines as a kit, how strange.
BTW, how long do the wheel bearings last? I have 223K miles on them. I did have to change the front axles at 185K .
J

[Ricky Bobby]

The fronts usually go before the rears - if you aren't hearing howling they'll be fine - some peoples go early and some outlive the vehicle -

I bought 1M of vacuum line from BMW (to use for the sections of check valve and on the L fitting off the intake elbow), the SAP "pipe" (it comes as an assembly with 2 vac line sections and the pipe, for $18 I think), and the vacuum caps for the back of the manifold -

RealOEM.com - Online BMW Parts Catalog
#3 (comes as assembly), #4 vaccum hose (sold in lengths of 1M)

RealOEM.com - Online BMW Parts Catalog
#15 and #17 (vaccum caps)

Along with the intake elbow (if needed), I replaced #3 in this - my original one was fine but I was trying to take care of all possible vaccum leaks via aged rubber at the same time -
RealOEM.com - Online BMW Parts Catalog


Hope that helps man -

[Bmwtvboy]

Delay followup: Got it all fixed up. Better idle, excellent gas mileage even with A/C. No more SES light. Now I have to deal with the trifecta lights again. Oh well. It runs nice though. Thanks

[williamx5]

Good day!!

Reading this post and the other one concerning the lights, it sounds almost like the tone ring in the wheel bearing is too dirty to pass a good signal... Ask me how I know this happens?! So, if you can get in there with some degreaser or brake cleaner and compressed air, you might get lucky...

Let us know what you discover please!!

Cheers!!!

[Bmwtvboy]

Sounds promising. But what and where is this tone ring? And do I clean both the right rear and left front ABS sensors? Am I spraying cleaner down into the open ABS sensor hole to clean it? Have never touched the left front. BTW, so I am sure, I believe there are only two ABS wheel sensors on this model. Thanks
PS. So, how do you know this issue?

[wpoll]

The tone ring is built into the inner dust seal on the wheel bearing. I guess on front wheel bearings, it's important to mount a new one the correct way around when replacing one!

BTW, the tone ring is the slotted disc the sensor detects rotation from.

[Bmwtvboy]

When you look down into the hole where the sensor goes you see the slotted disc. I imagine I spray cleaner and turn the wheel to get it cleaned. You show the front disc. Why does the code say rear. In all the years I've owned this X it's never coded a front wheel. I 'll clean both, but are those sensors interchangeable from front to back visa versa?
BTW, yesterday, I backed up until the light went out, 30 feet. Than drove round and round the parking lot, 100 feet , lights stayed out, overjoyed when the ABS kicked in on the rain soaked pavement. Headed out the drive about 100 yrds. down the road and bingo; lights back on.

[Bmwtvboy]

This is really strange. The backup trick works only when I first start up the car. When the lights come back on and I drive for while and then try the backup trick they won't turn off. Even after several 100 feet. Going to try and clean those toe rings out this weekend.
Thanks for all your help.