[Aramis]

Hello everybody

This is my first post since I bought my Alfa 2 months ago, this might sound like a strange question:

When I brake very hard from high speeds, shouldn't the ABS dashlight come on, showing it is working? If I say drive 80-90Km/h and do a full emergency stop, the brakes byte hard and nicely but if I push the pedal really hard, it reaches a point where it is on the floor but the car is still going forward, almost like bad pads but I checked the pads they are OK. This doesn't always happen. Sometimes I get wheel squeel from the hard braking. Is this normal? What about the dash light, isn't it supposed to come on on hard braking? on VAR the light comes on and then off, doesn't stay on.

Also, When I bought it, soon after that, I had a warning light come on, ABS&VCD&EBD system failure.

I connected via the OBDII, no faults on ABS....

I also forgot to mention, there is no pulsing from the pedal at all.

Any ideas or do I just misunderstand how the ABS is supposed to work?

Thanks in advance for all the help.

Cheers

 

[warniegt]

I've had the failure light come on as well once, and like you there was no problem and I haven't seen it since.

Mine also had new pads and disks all round before I bought it and like you under heavy breaking it just pulls up as normal. I wasn't impressed to be honest with the breaks, considering the size of them, but some repeated heavy breaking from 70mph + sorted it.

 

[sprint_veloce]

I don't think the light will come on to signify the ABS is activated, only if there is a problem with the ABS system.

However, if you can push the brake pedal right to the floor then you need to start by bleeding the brakes

 

[jwq]

ABS light will only come on in the case that wheels start to block, and ABS system needs to reduce braking pressure.... As long as the wheel is still turning and has sufficient traction, you will not get ABS activation.

So whether ABS engages, also depends on the effectiveness of your tires, brakediscs and pads and maximum brakeforce you can achieve....

edit: looking in the instruction manual, the ABS light is (only) an error indication for the ABS, and should normally not come on. The only indication for activated ABS is the pulsing in the brake pedal.....

see page 66 and 134 e.o. : http://data.manualslib.com/pdf2/45/4495/449435-alfa_romeo/gt_owners_manual.pdf?8194cb0cdfcaf44c4229e30814d5b33d&take=binary

 

[AussieAlex]

The ABS light won't come on when the ABS is activated. As jwq said it only comes on as a warning light. It will also come on for about 3 seconds and then turn off when your turn on the ignition.

Regarding the ABS/VDC error that can be caused by a battery on its way out as the battery may be providing insufficient voltage on startup. It may provide just enough juice to start the car but the ECU will still log an error if it doesn't detect sufficient voltage. Check your battery with a voltmeter. Should read above 12.6V

 

[Aramis]

Ah thanks for clearing that up.

So the light only comes on if there is an error and as long as all 4 wheels still have traction I should not expect any pulsing from the pedal unless I am on a wet road and a wheel is just before locking the pedal will pulse and abs is active?

Yes, I can push it all the way to the floor (if I am braking from high speed i.e. 140-160). Don't get me wrong, it does brake and brake good just feels like as I am approaching wheel lock, the brake gives way and slightly releases? Does that make sense? no pulsing though...

I am coning from a car without abs so this is all a bit new to me

 

[ransoman]

When triggering the abs you will feel the brake pedal violently judder moments after you feel the wheels locking. The Abs light will flash all the time the system is intevening.

If you are not seeing or feeling this, you probably haven't actually locked the wheels and your brakes are in need of a service.

I am on my 5th or so car with ABS and this has been the case in all of them. I always keep my brakes well serviced. Trust me, you will know when the ABS intervenes, even on snow.

 

[Paddy OPlastic]

If you can press the brake pedal all the way to the floor then there is definitely something wrong. It could just be air in the hydraulic system and a brake bleed should be the first thing to try.

You won't get ABS DTCs from OBD2. You'll need to use something like Multiecuscan along with some cable adaptors.

 

[Chris155]

Ah thanks for clearing that up.

So the light only comes on if there is an error

Yes. And if it is on the abs / stability control / traction control may not work.

and as long as all 4 wheels still have traction I should not expect any pulsing from the pedal unless I am on a wet road and a wheel is just before locking the pedal will pulse and abs is active?

Under braking, if any one wheel starts to loose traction (under rotates) the abs will kick in. It should be the fronts that lock up first.

The brake pedal pulsing means that the system could be modulating brake pressure. Or it could mean the brake discs are "warped".

It could also be that the steering angle sensor is reading the wrong angle fooling the system into thinking the car is under or over steering. - The stability control brakes wheels to pull the car into what it perceives as being straight relative to its yaw sensor(s) wheel speeds and the steering angle.

So if you're breaking lightly and feel it kick in round a bend this may be why.

Yes, I can push it all the way to the floor (if I am braking from high speed i.e. 140-160). Don't get me wrong, it does brake and brake good just feels like as I am approaching wheel lock, the brake gives way and slightly releases? Does that make sense? no pulsing though...

Sounds like you have a problem.