Traction Control/Throttle Issues

[cowfarmer112]

An issue has popped up recently that has me really scratching my head. The car starts up and idles just fine, no codes checked with a basic Bluetooth obd2 scanner and the torque app. When I'm in 3rd gear or 4th gear at about 2500rpm if I stomp on it the TC light immediately comes on. It'll even do it if I slowly roll into the throttle. This doesn't seem to happen in lower or higher gears though. If I turn the TC and stability control off completely the power reduction due to the interpreted "loss of traction" goes away but it's like the throttle is erratic and sometimes stays on in higher rpms in 3rd and 4th gear. For example, if I'm in 3rd gear at 60mph and and let off, it'll still stay at that rpm for a second or two and then start coming down somewhat erratically with the engine braking. I do have a sprint booster v3 installed, but even with it off all the symptoms I mentioned are still there. I've disconnected and reconnected the battery to see if that would clear anything, but no luck. I've looked on what seems to be every forum or thread and some possible culprits could be a wonky ABS/wheel speed sensor or a bad throttle pedal, but I have yet to grab my multimeter and check. I'm going to take off the sprint booster to see if that fixes it but as far as I can tell the only thing that would be wrong there would be a faulty connection and I know from experience that an incomplete connection with the throttle pedal results in full limp mode. I'll get a video of my gauge cluster with the symptoms in the coming days if that helps. Any and all thoughts on what this could be are greatly appreciated.

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[cowfarmer112]

I took the sprint booster off completely and took this video of the aforementioned symptoms. I also failed to mention that I had a brake line burst and then replaced about 2 weeks before all this started happening. Maybe ABS module has some codes that need read, not quite sure though since the ABS light has never came on even when the line burst and my brake pressure went to almost zero.


https://youtu.be/2IqdbQbCx7I

[cowfarmer112]

Update: I have since solved the issue at hand, but ripped my hair out along the way. I replaced both rear abs sensors and the front left. No change. I went to a shop nearby to get my abs module scanned and they pretty much told me yeah you might have to replace both rear axles which would've been around 1800 all said and done. Screw that. Instead of having a shop scan my car everytime, I invested in Carly and the BMW specific software that allows you to scan every module on the car. I highly recommend it. Despite all that I finally just ordered new front wheel hub/bearing assemblies that had shiny new abs reluctor rings and guess what, all my problems went away. The reason I was getting all the errors was because the reluctor ring on the front left was touching the abs sensor and making the entire system go haywire. Multiple times I'd get DSC errors for all of the abs sensors after scanning. Oh yeah, the reason the shop told me about the rear axles was because the abs reluctor rings can swell if you're in a rust belt state and cause the same issue, however, the reluctor rings are on the axles themselves, unlike on the hub in the front.

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[ZHPizza]

Wow good info! Thanks for updating us scrubs that didn't offer any help the first time you posted lol

[zhpnsnv]

This happened to me a couple years ago. Random, intermittent DSC intervention. Looked at the wheel speed sensors in the rear and they were worn down because the reluctor ring was making contact with them (swollen from rust). Luckily new sensors solved it for me.

I'm sure these sensors will wear down as well at some point.

Good to know the reluctor rings in the front aren't as costly.