Technical ABS trying to kill me

[andrewtj]

Hi everyone,

Need your help to stay alive with this car!

I got my '00 B from an owner who changed some hub bearings and has his ABS light on. 'Aha!' - thought I, remembering there are 3 different types of bearings (no ABS, teeth wheel, magnetic wheel), and sure AF he confused those.

So I connected the MultiEcuScan, looked for the errors - bingo! - incorrect number of teeth on phonic wheel. I cleared the errors and made a test ride to see the error appear again.

It didn't. But instead, ABS now kicks in every time I'm driving fast (>80 kph), preventing me from braking. COMPLETELY.

If I brake right after a pedal-to-the-metal kind of acceleration, the brake pedal turns into stone for 2-3 seconds, and it sounds and feels like ABS is kicking in - but the light is still off - and only then it "releases" and lets me brake normally.

WTF is that?

 

[MrDerv]

Incorrect number of teeth will be the problem. The sensor for that hub will be reporting the wheel travelling at a different rate of speed, ERGO the ABS kicks in.

They all need to be the same for ABS to work

 

[andrewtj]

Incorrect number of teeth will be the problem. The sensor for that hub will be reporting the wheel travelling at a different rate of speed, ERGO the ABS kicks in.

They all need to be the same for ABS to work

I thought so too, but how do I find out? The error doesn't appear anymore, and even when it did, it didn't show the particular wheel. More, MultiECUScan indicates almost identical wheel speeds (like 35kph for both front wheels, 33kph for both rear wheels). So it's either both wheels on one of the axles are faulty (but only for a few kph), or I don't know what...

The tires are nominally of the same size (maybe one axle is worn worse, but I can't see the difference on tire surfaces).