Traction control light over speed bumps?

jamesgarbett · Post by **jamesgarbett** » Mon Oct 04, 2021 11:23 am

Just something I noticed for the first time today
Going slowly over speed bumps I noticed the traction control light flickering on and off

Anyone else had this?
Anything to be worried about?

EthanS98 · Post by **EthanS98** » Mon Oct 04, 2021 11:49 am

I've never experienced this. However, when my ABS sensor failed it slowly starting applying ABS more and more often when my wheels weren't slipping. It started just in hard left turns, and eventually it was constantly showing ABs warnings in straight lines to the point I couldn't drive with ABS enabled.

If your ABS starts to come on at other odd times, I'd check your sensors or reluctor rings...

Nanu · Post by **Nanu** » Mon Oct 04, 2021 8:07 pm

Yep, have had the same experience especially when the speed bumps are of the larger type. Don't think it's anything to be concerned about unless you get airborne

flybobbie · Post by **flybobbie** » Mon Oct 04, 2021 8:24 pm

Could be dampers are shot.
What type of hump, full width or those square things.

tiglon · Post by **tiglon** » Mon Oct 04, 2021 8:48 pm

Absolutely normal over the nastier speedbumps. Every time I leave the house I have to go over three very short but prominent (full width) speed bumps and the light flickers as my rear wheels drop down the other side.

I think that when you go over a very short speed bump you are going up and then down so quickly that your rear wheels drop down at the exit while the rear of the car is still suffering the effects of being pushed upwards. The result of this is that there is far less downward pressure being exerted on the rear wheels and therefore you have reduced grip. Traction control steps in...

Happens less often if I am in Sport mode, which seems logical if my theory above is correct.

Of course, I know bugger all about physics so that might all be nonsense. Either way, I'm confident it's normal and your dampers are fine.

flybobbie · Post by **flybobbie** » Mon Oct 04, 2021 9:06 pm

I go over two speed humps twice a day, never seen the traction light on.
But have on undulating country lane, until i changed from stock to Bilsteins, now very rare unless hard accel. on gravelly road.

dhobbs · Post by **dhobbs** » Tue Oct 05, 2021 2:14 pm

I used to get this when I drive over a ridge in the road. Thought it was normal until I changed my dampers (at 100k), the rears were knackered. After the change the traction light didn't come back on.

Probocop · Post by **Probocop** » Tue Oct 05, 2021 2:50 pm

I used to get this on my old 1 series. As mentioned, it was my ABS sensor + reluctor ring, and also started eventually happening when turning.

Felixlamb · Post by **Felixlamb** » Tue Oct 12, 2021 10:24 pm

I had the same, mine was really bad. Luckily car was in warranty. BMW actually replaced both rear drive shafts as apparently they’d rusted (I assume swelling up the metal where the sensor would read from). Did fix the issue a bit, but it’ll still happen occasionally if it’s a really nasty bump, but no biggie. Tbh I’m on stock suspension which is stiff af so not surprised the car thinks something’s going wrong when a massive jolt goes through it.

B21 · Post by **B21** » Tue Oct 12, 2021 10:31 pm

As others stated stock response from the DSC system as the wheels unload and the system detects differential wheel speeds…

Both my E89s do it..since it relates to wheels unloading better suspension, better tyres help…

Since most E89s handle better with all the wheels on the ground just roll with it..then put the power on after the bumps

TomZ4 · Post by **TomZ4** » Sun Oct 17, 2021 11:50 am

I had exactly same issue yesterday!

I was doing over 20 on specific type of speed bumps (aggressive angle) and my front would jump a little and the light would flicker for a second. It doesn't happen anywhere else or at lower speeds.

jasper1000 · Post by **jasper1000** » Sun Oct 17, 2021 2:47 pm

Hi First post so please forgive me if its in the wrong section. I bought 4 x 10 spoke alloys with Bridgestone tyres. Used but all with 6 mm even tread. I bought them because my 4 x 10 spoke ones some were tracked and a couple of slow punchers. When ever I get to 50 /55 mph the traction Control light starts to flash and reduces power. Straight road smooth tarmac and dry conditions. Cannot go over 55 even by flooring it. If I turn the traction control off all is good. Only had this problem after chasing all 4 wheels. Any body shed any light on this issue thanks

B21 · Post by **B21** » Sun Oct 17, 2021 3:54 pm

jasper1000 wrote: ↑Sun Oct 17, 2021 2:47 pm Hi First post so please forgive me if its in the wrong section. I bought 4 x 10 spoke alloys with Bridgestone tyres. Used but all with 6 mm even tread. I bought them because my 4 x 10 spoke ones some were tracked and a couple of slow punchers. When ever I get to 50 /55 mph the traction Control light starts to flash and reduces power. Straight road smooth tarmac and dry conditions. Cannot go over 55 even by flooring it. If I turn the traction control off all is good. Only had this problem after chasing all 4 wheels. Any body shed any light on this issue thanks

Are the tyres asymmetrical?

I managed to embarrass myself with the garage fitting the rears the wrong way around…

What tyres and sizes are they?

Are they all identical?

jasper1000 · Post by **jasper1000** » Sun Oct 17, 2021 4:59 pm

Hi Thank you for the reply 3 are run flat Bridgestone but 1 (rear one) is a different make of run flat. Would have thought it would make a difference but worth taking it off and putting the old one back on to check. All the ones that came off were same run flat Bridgestone. Thank you will try that and let you know

ori · Post by **ori** » Tue Oct 19, 2021 12:29 am

My e89 used to do this. Always. 35 and 35is. I assumed it was the lack of give on the run flats.

I wouldn’t worry, however some people saying it might be shocks?

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