How can i (if i can) see wich sensor turns on ABS when i press the brake?
I can get FiatECUscan but i'm not shure that he can do that.

hellboy152 said:

How can i (if i can) see wich sensor turns on ABS when i press the brake?
I can get FiatECUscan but i'm not shure that he can do that.

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Your abs is activating everytime you are braking at a guess?
If this is the case - i'd try looking at the sensor rings on the front shafts, as there is possibly a crack in it - so the car is seeing a lockup when it actually isn't

Ziggy

Yes, you're right. ABS is always active.
I didn't have time to remove all wheels but i found little damage on left sensor ring (little peace of rubber is missing). You think that this damage is cause of ABS turning on?

hellboy152 said:

Yes, you're right. ABS is always active.
I didn't have time to remove all wheels but i found little damage on left sensor ring (little peace of rubber is missing). You think that this damage is cause of ABS turning on?

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Pictures?

Soon as i can. I didn't remeber to take them when i was disassembling. Tomorrow doubt it, so probably day after tomorrow.

I don't have tools for disassembling front bearings, but this is on the left rear wheel.

In MES log into the Abs module and with the car off the ground rotate the wheels, the diagnostic readout son screen should reflect the motion of the wheel so just look for the one with no signal output/doesn't show any movement

I've tried that (in drivig) but all wheels shows movement. When i'm driving logged in ABS module, ABS is turned off.

I would suggest your abs pump is faulty then

But ABS work's fine on heavy braking.

ABS sensors a basicly a magnet.

id be cleaning away some of that rust,

it might not solve it..but it cost nowt to try.

On heavy braking - good chance the abs will activate
Why?
its sensing a near wheel lock situation on 1 or more wheels
So the ABS overides to ensure the wheel doesn't actually lock up

It goes through 3 phases after the original brake pedal application
So the ABS unit detects a wheel is rapidly slowing down - ie its about to lock
It enters its 1st phase
- Pressure maintain
the 1st phase locks any extra pressure been applied by the driver to the offending wheel to prevent total lock up

2nd phase
- Pressure release
Car detects that wheel is again still rapidly slowing down, almost about to lock up, the release valve is opened removing the pressure from the offending brake, allowing wheel to speed up again, this fluid is then pumped back around via a buffer for reuse

3rd phase
- pressure increase
The car now see's the wheel is spinning at a similar speed to the others, but you are still requesting anchors to the max
The car allows pressure to be built back to the offending wheel to reapply the braking force

This 3 phases will constatnly keep repeating if 1 wheel is about to lock

Ziggy

I will try with cleaning first (least expensive option), then repleacing bearing from pictures.
If ABS pump is in faliure i thing that warning light would turn on.

So you have NO abs warning light

the abs activates all the time - regardless of braking pressure

This is telling me 1 thing - its 1 of the rings has a flat spot causing it to think there is a lockup when infact there isn't

Using a live readout via MES - you need to rotate the wheels to see which wheel has the "flat spot" that makes it think there is a lock up

Ziggy

Ziggy122 said:

So you have NO abs warning light

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Worth noting the ABS light should be flashing when the ABS is activated, so when braking and losing traction the Abs will activate and the dash light flashes

The complete lack of this light points again towards a bigger issue.

I still think the ABS module it's self is at fault and not the week sensors

AndyRKett said:

I still think the ABS module it's self is at fault and not the week sensors

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I hope you're wrong.

Today i've finally changed bearing from the pictures on first page and now everything works fine.