Technical Abs Light On Information Please

[c5martin]

I have a 1997 Fiat Marea HLX Weekend Estate with the ABS light on all the time.
Have measured the resistance of the wheel sensors which all read the same.
Intend to check the O/P on my Oscilloscope. Am I correct in thinking that the ABS sensors are scanned at switch on and also after you have started to move? Also if a fault has been memorised by the ABS computer that it is not reset until you have started the car 20 times with the fault cleared. Are there any voltages that can be checked at the sensor plugs? I have only just got the car and very please with is apart from this problem so any help would be appreciated.

BFN
Martin

 

[polecat]

Best thing is to get it checked out. First I've heard about the 20 starts thing.

Oh and welcome to our forum

 

[c5martin]

Hi,
Thank for welcoming me to the forum.
Faults so far with my car,
Replaced rear wiper motor,
Mileage indicator lamp
Rust on front edge of sun roof.
Lockable Wheel nuts replaced as had no key,
Blue key cloned.
Next is the ABS will perceiver for now as I have always work on electronics repairs in one way or another.
I am very happy with the car.
BFN
Martin

 

[polecat]

Oh the joys of being a FIAT owner

 

[Nickmey]

I have a 1997 Fiat Marea HLX Weekend Estate with the ABS light on all the time.
Have measured the resistance of the wheel sensors which all read the same.
Intend to check the O/P on my Oscilloscope. Am I correct in thinking that the ABS sensors are scanned at switch on and also after you have started to move? Also if a fault has been memorised by the ABS computer that it is not reset until you have started the car 20 times with the fault cleared. Are there any voltages that can be checked at the sensor plugs? I have only just got the car and very please with is apart from this problem so any help would be appreciated.

BFN
Martin

Just have a close look at the ABS cables coming from the rear brakes - most likely either one or both have been damaged by flying stones or bitten through by rodents. If you can read out the ABS computer (the connector is under the bonnet - 3-pin connector on the left, facing the engine - you will get an accurate listing indicating exactly which sensor has failed.
Nick

 

[CFREITAS]

. If you can read out the ABS computer (the connector is under the bonnet - 3-pin connector on the left, facing the engine - you will get an accurate listing indicating exactly which sensor has failed.
Nick

Or you will get the message I got which was "Braking system unknown"

 

[harrypp]

I have the same problem on a TD125 that I am attempting to sort out. Has anyone used multiecuscan or any other diagnostics to successfully communicate with these older abs systems?

 

[CFREITAS]

Have you guys tried replacing the rear ABS sensors
Are a common problem with cars with discs at the rear

 

[montecatini]

I have the same problem on a TD125 that I am attempting to sort out. Has anyone used multiecuscan or any other diagnostics to successfully communicate with these older abs systems?

I have used the Multiecuscan on my W Reg 1.6 Weekend. Showed me a fault on front Abs.
Bit of messing around at first (operator error) but certainly worked fine once I'd sussed it.

 

[harrypp]

Thanks for the replies. I need to get myself sorted out with Multiecuscan. Will report back.

 

[franglais]

seeing as this is an old thread and has already been hijacked, i thought it might be a good place to ask a (silly?) simple question.

i have had the ABS light on since i bought the car, but i have never actually paid ANY attention to it (to the point i never noticed the lack of ABS unit, or the 4 brake lines on the master cylinder), but now i have managed to make my diagnostics adapter work, i thought i might like to identify the problem.
well, i think i have found the problem, i don't have ABS, and have never had, ABS.
what i think has happened is that before i bought the car, the previous owner changed the cluster for the MOT, due to it having bad connections, they must have changed it with one that is expecting ABS to be present.
my question is therefore, is there an electronic way to get the cluster to not expect ABS, or should i just take the thing apart and remove the bulb?
many thanks in advance.

 

[steve20vt]

If it's an early one it's just a case of taking the bulb out. On my late Brava cluster the warning lamps are LEDs. Which I suppose you cut just snip off.

The cluster is easy to get out. I think it's just four 4mm Allen bolts and a screw under the vent for the cover and then four 4mm Allen bolts for the cluster.

 

[Raziel]

ABS warning light is LED and cannot be removed.
But on the back of the cluster, there are two holes for bulbs which are fitted with white, empty caps (they look the same as regular bulb holder, they are just white).
This empty holes can be used to short circuit (bridge) and turn off ABS and airbag warning lights. You can just do it with a piece of wire soldered on the empty bulb holder.
I found this information in Marea's service and repair manual. If you'll need more detailed explanation, I can copy this section from the manual.

BTW; Multiecuscan cannot connect to ABS unit fitted on Mareas built before '99. (Marea 2.0 147 in example). I was able to connect to it with professional diagnostic tool. Both of my front sensors are gone.
Also, this old type of Lucas ABS unit is known to fry relays inside of the control unit. Info about it and how to repair it can be found on this forum.

 

[steve20vt]

Excellent info. I did wonder what those two blank bulb holders were for.

 

[franglais]

i had the cluster out a couple of weeks ago and written on the back, in messy handwriting on an old sticker is "Marea JTD" so it looks like the garage that changed the cluster weren't fussy with what they put in. i do wonder, could this explain why my radiator fan comes on when the needle is only half way?
i can comfirm that on the JTD cluster, the important ones are L.E.Ds, i might have another look and see if the white bulb holder trick works, although i dont have the best memory, i dont think i saw any white ones.

 

[Raziel]

Yeah, it may be that there are no white ones. In that case just pull them out one by one and look for the blank ones.
From your photo, I can see that cluster is from the "facelift model". I've used one like that from Marea 155 on my Marea 147 but returned to original one because temperature gauge would not go over half no matter how hot the engine was. Also, speed readings were off and I had trouble with check panel.

I suspect that coolant temperature sensor might be different on older and newer models so you could try to change the sensor for one from JTD.