Flashing DSC while turning — after changing wheels and tires

[JPR10]

I’ve searched this issue and there is no definitive answer or solution since everyone has had slightly different experiences.

Car is my 2002 530i. I had a set of m parallels that has bends in the front wheels that caused vibration at many speeds.

I recently acquired a set of staggered style 65 wheels w/ A/S tires (Falken Ziex ZE912) where the 2 fronts have worn outside shoulders due to previous owner.

He claimed worn suspension but I’m guessing misalignment? Could be both.

I’ve put them on my car, torqued all wheels properly, added air to recommended tire pressure spec for front/ rear.

When I’m turning at moderate speed (b/w 30-50 mph), the DSC light will flash and slow my car through the curve. We are in completely dry conditions, and the wheels are not slipping.

I turned off DSC and confirmed this through another curve.

I haven’t ruled out alignment but I won’t be able to get an appointment for another week or so. Could the alignment, or tires be to blame?

Is my pressure sensor going bad?

What do you think, let me know.

[jmc1590]

I'll be the first to ask, did tire size / profile change with the new wheels?

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[JPR10]

I'll be the first to ask, did tire size / profile change with the new wheels?

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Yes. I went from 18x8 squared (fronts from e39 et20, rears from e38 et13).

Tire sizes:
Front: 235/40/18
Rear: 245/40/18

Now I have OEM style 65s w/ these tire spec:
Front: 235/40/18
Rear: 265/35/18

Also, here is the pic of the tire wear on the fronts. The passenger side is identical.

IMG_0044.jpgIMG_0045.jpg

Rear tires are like-new.

[JPR10]

Another thing to consider:

- My front tires are the same diameter as the old setup
- My rear tires are actually smaller in diameter by 0.4 inches

Can this contribute to the issue?

[Mike WW]

Another thing to consider:

- My front tires are the same diameter as the old setup
- My rear tires are actually smaller in diameter by 0.4 inches

Can this contribute to the issue?

Absolutely. ABS/DSC etc all run by comparing wheel revolutions, so if one or some are more or less than the others it sees tire slippage.

[JPR10]

Absolutely. ABS/DSC etc all run by comparing wheel revolutions, so if one or some are more or less than the others it sees tire slippage.

Interesting... any thoughts on a solution? Will I need to buy a pair of tires one way or another?

[CPHES]

You have tire diameters that are different - either due to wear, or size that is causing dsc to throw these errors. I think the difference is .03% across tires / rolling diameter

[JPR10]

You have tire diameters that are different - either due to wear, or size that is causing dsc to throw these errors. I think the difference is .03% across tires / rolling diameter

These are the specs of the tires and the variances.

Are these out of spec?

[geargrinder]

Should not be enough to cause a problem like that. The system needs to take into account way more wear than .4% I think. Think of all the 540's and M5's that eat up their rear tires... All the staggered setups guys run where the tires aren't exactly same diameter... DSC isn't known for phantom tire wear issues for sure.

I'm guessing the tires are slipping. Just because they don't go "SKWEEEEELLLL" doesn''t mean they aren't 'scrubbing'. Other thing would be, these wheels don't bind or anything do they? Are they real E39 wheels? Right offsets and whatnot?

[CPHES]

The odd thing about his size, is they are one size under OE. An m5 should be 245/40/18 front / 265/35/18 rear. I would think it’s balanced, but..... are they worn evenly front and rear?

[bluptgm3]

How is pressure?


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[Liam79]

The odd thing about his size, is they are one size under OE. An m5 should be 245/40/18 front / 265/35/18 rear. I would think it’s balanced, but..... are they worn evenly front and rear?

M5 is 245/40, 275/35. Non M model 18" staggered is 235/40, 265/35. So he's running a factory setup and it shouldn't be causing DSC issues, even with one axle's tires more worn than the other. I'd be first checking the ABS rings are clean and after that considering things like possible faulty ABS sensor or maybe even steering angle sensor.

[JPR10]

Should not be enough to cause a problem like that. The system needs to take into account way more wear than .4% I think. Think of all the 540's and M5's that eat up their rear tires... All the staggered setups guys run where the tires aren't exactly same diameter... DSC isn't known for phantom tire wear issues for sure.

I'm guessing the tires are slipping. Just because they don't go "SKWEEEEELLLL" doesn''t mean they aren't 'scrubbing'. Other thing would be, these wheels don't bind or anything do they? Are they real E39 wheels? Right offsets and whatnot?

To my knowledge they’re real based on looking at the inner faces and finding the BMW insignia.

I don’t think they’re binding either, and they roll fairly smoothly as they get up to speed on the highway.

[JPR10]

The odd thing about his size, is they are one size under OE. An m5 should be 245/40/18 front / 265/35/18 rear. I would think it’s balanced, but..... are they worn evenly front and rear?

As pictured above, the fronts have unusual wear especially on the outside shoulder due to worn suspension components on POs car.

They also look to be more worn in general compared to the rears.

[JPR10]

How is pressure?


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I filled it to 33/40 front v. rear, in accordance w the door sticker


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[JPR10]

M5 is 245/40, 275/35. Non M model 18" staggered is 235/40, 265/35. So he's running a factory setup and it shouldn't be causing DSC issues, even with one axle's tires more worn than the other. I'd be first checking the ABS rings are clean and after that considering things like possible faulty ABS sensor or maybe even steering angle sensor.

This is a good point... where are these ABS rings?

[geargrinder]

M5 is 245/40, 275/35. Non M model 18" staggered is 235/40, 265/35. So he's running a factory setup and it shouldn't be causing DSC issues, even with one axle's tires more worn than the other. I'd be first checking the ABS rings are clean and after that considering things like possible faulty ABS sensor or maybe even steering angle sensor.

Yeah, just seems weird that it'd happen after the swapparoo. A bad wheel sensor would cause more problems and probably light the light all the time.

HOWEVER... I like the LEW idea (steering angle sensor). I wonder if because of the bad cupping on the fronts, he's having to turn the wheel farther than the DSC expects for the yaw and wheel speeds that it is detecting!?

I'd really like to see if the ABS/DSC has any codes it wants to share...

[BimmrMeUpSnotty]

Anyone think about slapping the old set of wheels back on? See if the craption cuntroll light screws off? Doubt it...

[BimmrMeUpSnotty]

Another thing, those Falken tires a falken crap, when new. I’m betting those tires are rock hard, and spinning on you, causing the dsc to work. I bought at set of those crappy tires back in my VW GTI days, they were crap, fresh from Tire Rack, they were a hard compound and sucked big balls.

[JPR10]

Yeah, just seems weird that it'd happen after the swapparoo. A bad wheel sensor would cause more problems and probably light the light all the time.

HOWEVER... I like the LEW idea (steering angle sensor). I wonder if because of the bad cupping on the fronts, he's having to turn the wheel farther than the DSC expects for the yaw and wheel speeds that it is detecting!?

I'd really like to see if the ABS/DSC has any codes it wants to share...

I tried plugging it into INPA but I may have an incomplete version or something.

I’m getting this error when I try to read the ABS/DSC modules:



Any other thoughts of how to get to those?

I do want to add that sometimes I’ll get the yellow brake and DSC light to stay on during a drive (without doing anything) which tells me that my ABS/DSC system is a little faulty.

What could be causing this?

[Liam79]

That's odd - can you connect OK to other modules? If you are getting the lights staying on sometimes you all the more want to read codes to be pointed in the right direction!

About the ABS rings - more of a non-car-specific comment from my general experience. If I recall properly now, for E39 the front is well hidden within the hub assembly, so unlikely it is rusty/dirty. The rear ring should be on the driveshafts (er, halfshafts in American? ) just inboard of the wheel bearings. Not sure if they are visible enough to be inspected and cleaned if necessary.

Starting with the very basics though - if you're happy to replace the tires (or maybe planned to do anyway), get that done first and see if it goes away. Seems unlikely it could be them to me as apart from some outer shoulder wear due to PO's bad alignment they don't look too bad, and the fronts being slightly more worn than the rears would bring the diameters closer towards being the same front and back which has to be even more within the working window of the system for the majority of cars with non-staggered wheels! But it rules out a variable if you gonna replace them anyway.

[JPR10]

That's odd - can you connect OK to other modules? If you are getting the lights staying on sometimes you all the more want to read codes to be pointed in the right direction!

About the ABS rings - more of a non-car-specific comment from my general experience. If I recall properly now, for E39 the front is well hidden within the hub assembly, so unlikely it is rusty/dirty. The rear ring should be on the driveshafts (er, halfshafts in American? ) just inboard of the wheel bearings. Not sure if they are visible enough to be inspected and cleaned if necessary.

Starting with the very basics though - if you're happy to replace the tires (or maybe planned to do anyway), get that done first and see if it goes away. Seems unlikely it could be them to me as apart from some outer shoulder wear due to PO's bad alignment they don't look too bad, and the fronts being slightly more worn than the rears would bring the diameters closer towards being the same front and back which has to be even more within the working window of the system for the majority of cars with non-staggered wheels! But it rules out a variable if you gonna replace them anyway.

I had not planned to replace the rears since they are essentially new. I'd like to maybe get a set of matching fronts if I can find them -- but I'd like to sort out this ABS issue first (at least understand if there are other/underlying issues)

I can connect to the engine module and read/clear error memory from there. I believe I can read the trans module also. When I try anything other than that, I receive that error message.

I'm going to see if my indy can plug in his fancy Snap On Solus to see if he can read the ABS module.

Is it worth the time and effort to slap on the old wheels to see if it alleviates the issue under the same circumstances? I would hate to buy new tires for the wheels and find out that the tires are not the issue.

[BimmrMeUpSnotty]

Activate some brain cells... yeah, shove the old wheels on to see if it is still doing it, obviously, something changed when you put the current set on right? Wow...

[JPR10]

Activate some brain cells... yeah, shove the old wheels on to see if it is still doing it, obviously, something changed when you put the current set on right? Wow...

Laziness is setting in lol. Will try it this weekend.

[geargrinder]

I can connect to the engine module and read/clear error memory from there. I believe I can read the trans module also. When I try anything other than that, I receive that error message.

I'm going to see if my indy can plug in his fancy Snap On Solus to see if he can read the ABS module.

Your cable is probably a cheapo VAG-COM or something? If you can only see DME/EGS then it needs pins 7 & 8 bridged to reveal the wonderful world of the rest of the car. Just open up the shell, solder across those 2 pins, and try again.