ABS/ASR activates on hill

Hi!

I have this really strange problem with this model I am testing. The issue is that abs/asr system activates on its own whenever the bus starts going uphill, after a station. And it always activates when it's supposed to switch to 2nd gear, after it finally switches the gear, the systems deactivate and bus is normal afterwards.
I have tried looking into scripts trying to find the problem and I can't seem to find it. I tried everything, switching the systems off in script, changing values for gears, nothing works. Can someone help me with this?
Thanks in advance!

Unfortunately I can't reveal which bus it is. The wheel diameter is the same for all wheels, 0.94, like it's on other bus models I looked into to see if there is any difference. I thought about changing, but then I saw (looking into another thread where a model had different diameters of wheels and they changed the values in bremse script of bigger diameter) that it doesn't need correction of values in bremse script. Here is the full script of the abs part:

I mean, it's pretty much the same like any other model that has abs, I am really baffled on why it doesn't work properly, or why it activates when changing to 2nd gear. I contacted another member of this forum that made a modification to one of the models and they had the same issue with their mod and they fixed it. Unfortunately, the member hasn't answered me at all. So thank you for trying to help me!