Hi, a little while ago i had the abs unavailable come on. A friend of mine has a genuine delphi machine so he tried that and it said front left sensor. I bought an aftermarket one, had the code taken off and it worked for a week before it came back on again, same reason according to the delphi. The guy said perhaps it was a bad sensor so i bought another and took the old one back.

After putting this one on the connection seemed loose where it attaches to the wiring loom so i also taped it up. Yet again 2 weeks later it came on again. Bought a 3rd one, same again (by this time i had bought my own delphi (fake one obviously but it read and removed codes so i was fine with it). Again front left sensor. I figured it must be the connection.

By this time the motor factors said the 1st returned one had been tested and was fine, refused to give me my money back so i wasnt about to buy another. I decided that as i had a spare and the connection was iffy at best i'd cut the wires and join them with a terminal block. Worked for 1 full day then same again.

This first happened after a car wash (ive read on google this is a common occurence). 2nd time exactly the same and today it was raining so ive wondered if water is part of the problem. Someone mentioned an abs ring (after removing the sensor i can see down the hole. Ive been told theyre toothed but all i can see is a sort of disc, similar to looking at the edge of a brake disc, am i looking at the wrong bit?

Anyway, big problem is im a driving instructor, they wont let the car go out on any more tests until this is fixed. Ive only just started the job and cash is tight, the cars already been into a garage the first twice i had this sensor changed so i cant afford to keep doing that. I tried the last one myself but obviously that hasnt worked. It is an intermittent fault which makes it even harder to sort but if it comes on in 1 more test the car wont go out.

PS, the delphi has said permanent fault first time and present fault the last time. Always front left sensor. Any help is very much appreciated as i have 4 tests in March and dreading each one of them. I can take the code off but know it will just keep coming back on. I have called another garage who have told me that even tho i have my own machine theyll only use theirs and will charge £30 before even looking at fixing the problem. Thing is i KNOW their machine will say sensor and theyll just suggest buying another which is a total waste of time and money. Please help

Hi Basil (is that correct ?) and welcome on board this forum !

Remove the ABS control unit connector and check for moisture / oxydation on the pins ; it should be PERFECTLY clean: no green, no damp, no dust, no nothing. The signals going there are very sensitive to bad connections. Re-sit the connector and tell us what happend...
To remove the connector you need to rock the plastic lever while pulling gently on the connector, reverse way to put it back, You'll see clearly once removed ...

Regards, Bernie

BTW: would be nice to know what car it is...

Thanks for the advice, where would i find the control unit? Ive onlt messed about with the wheel part up to now. Im guessing its somewhere on the engine but have no idea what it looks like.

PS i should have mentioned i have a 59 plate 1.3 diesel multijet grande punto, not sure if that makes a difference

Located behind the battery, under the brake fluid reservoir, You will see a large black connector ('bout 3 x 1") with a rocker lever on it, that's him. I will try to find some picture, which model is it ?

Regards, Bernie

No, its ok thanks, ive found the pic, just behind the battery. As it happens the reservoir on mine is on the other side but i should be able to find it. Ms is driving it just now but will be back by 930 latest so i'll take a look to make sure i can find it but will probably have a go a fixing it tomorrow as its raining badly here and i dont want to make it worse.

I'll be happy if it is this but more than a little upset that ive gone through 3 sensors and 2 garage visits without this being mentioned before. Its a 1.3 multijet diesel 5 door grande punto. Thanks for this help btw. Any ideas what else it could be if it s not this?

Only ABS not available or also EBD ??

ABS "ring" is on the end of the driveshaft. Look at a photo of shaft like here and you'll see a silver coloured toothed ring at the end of the CV joint:

At this time i would suspect the abs ring.

can you see individual wheel speeds on your interface?
that is how you test.
intermittent/variable speed at constant speed is a giveaway of ABS rings.

bernie, ive found the control panel, too dark and wet to check now but will first thing tomorrow. No EBD lightDGPunto, ive only looked down at it through the hole thats left after the sensor has been removed so can't say for definite but when i look down that hole its a smooth bit of metal, not toothed at all. Obviously without taking the disc off i cant see the driveshaft like in the pic but surely the toothed bit is what the sensor should be over? Aurick, im not sure, ive never tried a wheel speed test but this kit ive got is supposed to do everything the real delphi can. God knows how id find that setting but i'll look tomorrow. As for it being the abs ring the garage i took it to originally said that not all puntos have a toothed abs ring, is he right?

If it is the ABS ring you can buy them. For example Here

The ABS ring can either be toothed or magnetic... both do the same thing... but in a slightly different way.

If it's magnetic.. and it cracks. you will get abs errors.. or he ABS pump will kick in at all breaks all speeds.

Mornin' !

I believe you'd have to remove the drive shaft from the wheel hub to see the ABS ring.
Trick: remove the right sensor to see if it looks the same inside the hole ...

Regards, Bernie

Thanks all. I cant tell if its magnetic or not but ive looked down into the hole by the sensor and it definitely doesnt seem toothed. As for getting the driveshaft off im missing a 32mm socket so cant do that just yet but if im honest im not good with cars. Is it really easy to change an abs ring? Even changing the sensor i hit problems such as the sensor wouldnt come out so i used wd40, pried gently and the flaming thing snapped in the hole, i had to drill gently and put a screw in it to pull it out. Ive checked the ring and the drill definitely did no damage at all, didnt touch it. Car back now so im going to do the easy bit first, check the control unit. It is weird how it broke twice at a car wash and this time in a storm.

Just checked with motor factors. My car doesnt have an abs ring, the sensor picks up off the bearing. Talked to a garage friend who said he cant see it being that, especially since the 3 times its gone its happened in the wet. Said he's sure it has to be a connection somewhere.

Ive actually cut the plugs off this last sensor and connected them via a terminal block as i had a spare sensor. That's as secure a hold as you'll get and its got tape around it followed by a thick plastic bit and taped again so theres no way rain is getting at that bit. Ive taken the battery plug off now, giving it 10 minutes then wd40 the connections and pray.

Final update for now. I've taken the clip off and it looks brand new inside, no green or water at all. Sprayed with wd40 anyway, allowed to dry then reconnected everything. I put it back on the delphi and as well as getting the usual code had an extra one.

0030 - front right phonic wheel - intermittent
0031 - front right sensor - present

Im only guessing but im suspecting the phonic wheel is the problem now as im getting these problems intermittently. Thing is i may have caused the "present" problem which btw wont come off now even when i wipe the codes by messing with the connectors.

I did have images of the plug on my desktop to add but this only allows you to add from a website. Trust me though the plug is fine. Out of ideas now, dont even know what a phonic wheel is.

basil1492 said:

0030 - front right phonic wheel - intermittent
0031 - front right sensor - present

Click to expand...

The phonic wheel IS the ABS ring we were talking about earlier.

You need to measure the resistance /ohms across the sensor .. both close to the sensor.. AND at the ABS unit in the big connector plug.
somebody could help with the pinout.

You should be able to attach pictures...

- click reply icon
- below the reply window, click Go adavanced
- in the advanced reply window tool bar, click the paperclip
- in the attachement window, click Select file
- browse where your file is stored and select (open) it, it will show in the attach window
- you can attach 5 pics, once done click upload (not in the URL section !)
- the files will be in your reply message ...

BTW, don't know why they call that "phonic", but it's actually the ring, magnetic or toothed that actuate the sensor...

Regards, Bernie

Thanks aurick86, i'll get someone to do that for me.
bernie, I was using the gallery thing instead, ive included them here but i think the problem is the phonic wheel which unfortunately means a new bearing. My problem isnt getting one, my local motor factors have them, my problem is nobody can fit them for over a week and i have 3 tests i'll have to cancel by then costing me a lot of money and reputation.

Hi Basil,

no need to ohm check the sensor, they don't work like this. On your car model you shouldn't see any toothed ring since there isn't any. The encoder (phonic) wheel is integrated in the hub bearing, not on the drive shaft.
See pictures below...

Regards, Bernie

Bernievarian said:

Hi Basil,

no need to ohm check the sensor, they don't work like this.

Click to expand...

bernie
I was saying to check the resistance just to make double sure the circuit is not interrupted/bad contact between the ABS module and the sensor.

The sensor i believe is a hall effect sensor... so you should be able to measure some resistance.
I was in no way suggesting measuring it while the wheel is rotating.