Technical ABS light on

[trumpeter]

Hi All,
I have the ABS and caution lights on intermittently on my marea.
They usually come on after restarting the car if i do short runs.
They clear themselves if i stop and restart the car.
This has become more and more frequent over the past month.
Any ideas as to the cause and how to fix it would be much appreciated.

 

[mountainmachine]

Is the ABS working? Stop quickly from 30mph see if the peddal judders.

The lights should all come on when you start the car then go off after 10 sec or so.

 

[jug]

when you say abs and caution lights, which lights are the caution ones?

 

[trumpeter]

Ok.
ABS works OK. Not tried it when the light is on yet as it has not done it today! (Typical)
The caution light is the one next to the ABS light that usually comes on when the handbrake is on.

 

[mountainmachine]

Have you checked brake fluid level?

 

[trumpeter]

Fluid level is fine.

 

[mountainmachine]

Someone was having problems because there was corrosion on the cogs for the ABS sensor, try cleaning them up and see if that helps.

 

[jug]

i've never seen a fault with an abs sensor or the abs controller illuminate the caution light. an abs fault should not illuminate that light, in the same way a brake fault should not illuminate the abs light. they are completely independant. usually i would assume the abs light could be due to a wheel sensor, the controller, or the wiring associated with them. usually i would assume the caution light could be due to a faulty handbrake lever switch, low reservoir fluid, faulty reservoir cap sensor, excessive front pad wear, or the wiring associated with them. there is nothing common between the 2, unless the 2 circuits are sometimes connected by a wiring fault. since this problem is intermittent, and it only begins after a restart, it is probably due to faulty wiring, a damaged wire or corroded connector. i guess a wiring diagram is the place to start.

 

[Renegade_8]

A quick and easy check would be to unplug the wires to the pad wear sensors, if that cures it you know where to look.

 

[mountainmachine]

Are your rear brake lights working as some models have a warning for that!

 

[fbarcode]

I have the same problem on my Marea, and yes, both lights are on. It happens only when it is raining and I go over a bump, so I guess it has something to do with loose wire, or water blocking the sensor, or something like that.
When you I start the car next time, only ABS light is on and stays on for a minute or so.

But pay attention as when the ABS light is on, you will not have ABS, as ECU will disconnect the whole system.

 

[Migaard]

Hi.

I had the same problems last year.
The yellow ASB warning light came on, first periodically, and the alwas.
There is a weakness in the ABS control box, a relay may need to be changed.
I went at a FIAT workshop and had the system tested, they told me i had to have the control unit replaced 2.000£! NO WAY
Replacing the 2 relays in the box is a semi difficult DIY job.
Look at the Guides section, there's a really good guide in how to renewal the unit. There's a lot of money to save!

Michael

 

[trumpeter]

Hi all,
Thanks for the advice.
The problem seems to have gone away at the moment but i will try and have the wheels off next week and clean the rotors and also check the pads are OK. Is there any way to check the ABS sensors?
Thanks all

 

[jug]

Is there any way to check the ABS sensors?

a faulty sensor would bring the light on permanently so i wouldnt consider it a possiblity. you can check the gap, and the alternating signal produced when the wheel is spinning, but i greatly doubt a sensor could be faulty if the light is no longer on.