Good morning to you all. Have had an ABS speed sensor failure. It could be the pump as changing the sensor has not fixed it. Can anyone recommend somewhere to test and repair? I would rather go with a recommendation than pick one at random from Google!

Many thanks

Phil

It would help if you stated the model/year of your car ? 

 

I assume you changed the sensor due to a fault code ? if so what was the code ? 

OK - maybe a bit cheeky but it is my son's 59plate Fox! Lots of common parts including the pump as far as I can tell. The code is 0285 - front right speed sensor.

One thing that bothers me is the hub was changed by the garage last year, noisy bearing and getting the sensor out was very easy! It had signs of copper grease on it and maybe this has affected the ring? I have belled the wires through and all fine there and the resistance on the new and old sensors are the same! 

Just got a niggle it might be the pump. Bought one on ebay and have the same fault still and just thinking how unlucky to get another pump with the same failure, but if it is common then possible I suppose. Still, a bit unlucky.

I have also bought a hub from Stevens with the surrounding casting - handy to see how it all fits together if nothing else. I don't have the tool to take the hub out of the casting an tying to avoid that.

Garage wanted £500 to £1000 to diagnose and repair and that is more than we can manage at the moment.

You helped me greatly a year or so back with a head gasket issue on my 96 plate 6N. It went in the end and I replaced it with the same just 3 months newer and low mileage and it's lovely apart from the colour!

What do you think?

Kind regards

Phil

 

Not a problem as you say a lot of common parts.

 

After the 0285 was there any other description ? as there are three possible 

00285 - ABS Wheel Speed Sensor Front Right (G45): Signal Outside Specifications

00285 - ABS Wheel Speed Sensor Front Right (G45): Electrical Fault in Circuit

00285 - ABS Wheel Speed Sensor Front Right (G45): Open or Short to Plus

You say you have belled the wires, was that back to the ABS pump ?  Sensor pin 1 (Black wire) to pin 6 on ABS unit & Sensor pin 2 (Green wire) to pin 18 on pump unit. 

 

The setup on these later VW's differ slightly from the earlier models in that the older ones had an external reluctor ring that the sensor detected the wheel speed from, on the later they moved this reluctor ring to be part of the driveshaft and it is no longer visable as it's within the hub unit, so If your garage that replaced the hub was a bit over generous with the grease while fitting the drive shaft, it might be clogging the reluctor and so the sensor isn't seeing a good wheel speed signal, you could try removing the sensor and looking down the hole in the casting and you should see a clean section of the shaft with ridges on it, The other question was the replacement sensor a genuine one from VW/TPS or something from ECP/GSF/eBay ?  if it was from the latter I wouldn't be surprised if it was faulty !!

As usual - to the point and very helpful. Love it.

So, shorted the wheel end and took the connector off the pump. The new pump had the connector still and the new hub had the sensor connector still, so found the same colors and belled them through. Didn't go beyond that. It was the first pair on the connector, row five after 4 rows of blanks.

 

I looked in the hole and it is not clean particularly and no teeth - smooth. I found a can of electrical solvent and gave it a good blast of that and a bit of cotton bud! It's dirty for sure The new hub the ring is smooth and magnetic. Expecting this has an in built ring.

Did a GSF sensor but have put the old one back in as it has the same resistance. The resistance of the sensor on the new hub is the same too, so fairly settled it is not a sensor problem. Happy to be advised.

Just bothered that if it is a dirty ring it has taken very nearly a year to be a problem.

Tried to get the hub off yesterday and was oddly snookered by the track rod end bolt - first one I tried. Could not get the nut off and the hex was close to ringing, so bottled it and put it back together. Cleaned the thread and dowsed with WD40 , but the last few turns were just not possible. Have ordered a new one just in case I need to get it off in a way that it will not go back on! 

So, I am back to the pump reluctantly. MOT in 2 weeks!

Thank you for your comments anyway and all suggestions welcome.

Phil

 

 

 

That's the pin layout for the pump unit.

 

It's the splines that the sensor picks up on 

 

If you have VCDS ? you should be able to see from the measuring blocks the output from the sensor as you spin the wheel 

Nope - VCDS is not something I have. I did try with a pocket meter, connected 2 leads to the sensor to see if I could get any voltage. Ran the engine in 1st and 4th gears on tickover but nothing! So, did the same on the LHS and same result so suspect the meter not good enough ti pick up the voltage. Was a bit surprised but the same for both sides!

 

I'm not sure about the splines. The 'new hub' shows the sensor right close up to a smooth and magnetic ring. The ring is on the inner part of the bearing that the splines go into by the look of it, so rotates with the shaft.

Phil

 

Make a really thorough check of the rubberised cable down to the wheel for signs of damage . The coating can hide damage.

 

Also have the plug off at the wheel end and check it's not suffered any damage, particularly if you've any doubts about the garage that changed the hub.

 

I'd be very surprised if it were a pump fault. They're generally very reliable. 

Good point and I have made a good check and also rung it though to the pump and the circuit appears fine to me. The connector is clean and the same as the other side. It's the copper grease on the sensor that bothers me in case there is lots of it in there, but difficult to tell of course without taking the hub out of the casting.

It's a good garage - old school, so maybe never thought about copper grease and magnetic rings!

Kind regards

Phil

 

Have a read of this https://cardiagn.com/lupo-3l-ssp-218-online/ scroll down to page 38 it describes how the sensors detect and I was mistaken in thinking it counted the splines it  reads a track that is embeded in the wheel bearing seal 

OK - got it and learned a bit too. Checked my screwdriver and it was magnetised, so I don't think the ring was magnetised as previously thought!

This doc explains why I could not read any volts too, so that's good. It's the current that changes.

I have to get the hub off then and look at the seal. I think there is some stuff about copper grease and rubber/neoprene as well not being good with each other and there is no way through the sensor hole to see or do anything with the seal.

It's a job for next weekend now and will let you know.

As before, thank you for your help on this. I'm not one to give up easily and one way or another I will get it fixed....probably!

 

General feeling it's not the ABS pump then?

 

Have a good week

Phil

 

 

 

As @Yeti said earlier the pump units are generally fail proof, the early ones did suffer with a low voltage detected problem but that was due to a dry soldered joint going to the main motor with a totally different fault code to yours and the fix is listed in the FAQ's of this section.

 

The sensors are looking for a change in inductance (henrys or more like microhenries) so if you multimeter has an inductance setting then you should see a change as the wheel is rotated 

A quick update and also thank you for your helpful comments.

Took the hub off this morning, had to bin the track rod end in the end. It was very quickly clear what the problem was. The bearing was making ts way out of the casting, so the sensor was not anywhere near enough to the ring to do any measuring! 

 

I just put the 'new hub' on and have the old one still on the bench. I was really surprised as eventually I suppose the wheel would have cone off the car - assuming the drive shaft would part at the CV joint!

 

A quick question. Is it the nurling on the hub side of the bearing that locks it into the casting? If so, would I be right thinking that when the new hub was fitted a year ago this did not click in?

 

Anyway - all working and now need to get the tracking done of course!

 

Kind regards 

Phil

4 hours ago, Phil H said:

A quick update and also thank you for your helpful comments.

Took the hub off this morning, had to bin the track rod end in the end. It was very quickly clear what the problem was. The bearing was making ts way out of the casting, so the sensor was not anywhere near enough to the ring to do any measuring! 

 

I just put the 'new hub' on and have the old one still on the bench. I was really surprised as eventually I suppose the wheel would have cone off the car - assuming the drive shaft would part at the CV joint!

 

A quick question. Is it the nurling on the hub side of the bearing that locks it into the casting? If so, would I be right thinking that when the new hub was fitted a year ago this did not click in?

 

Anyway - all working and now need to get the tracking done of course!

 

Kind regards 

Phil

 

Wow I think you were lucky that what was an annoying fault light probably saved you and passengers from a nasty accident,  I've not taken one of those newer joints apart so I can't comment on the knurling you refer to, but I would certainly be having a word with your garage that changed it 

I expect what happened here is that your garage who replaced the wheel bearing/hub didn't use the appropriate Gen2 tooling, but just pressed it in by the hub surface.

This is like (exactly like, cos it is) trying to press a bearing into place by pushing only on the inner. Bearing damage and/or failing to get the outer fully into place are the likely consequences. Seems you have experienced the latter.

The proper tooling has to get in behind the hub in order to push on the outer of the bearing to get it fully in place. See here for example: https://www.youtube.com/watch?v=YEHRcL06fhA

 

Could be indeed. They're a nice bunch and have a great reputation locally so I am putting it down to an unfortunate, but luckily no serious outcome, mistake. I think it is fair to let them know for anyone else's car they do the same thing to.

 

I've seen the tool also on YouTube and may make the investment. We have 2 Polos, a Fox and an AudiA4 and with the state of the roads around here wheel bearings don;t seem to last long, nor the tyres come to that.

 

I used Stevens n Chelmsford for the 'new hub and housing' and for me they have been brilliant over the last few years. Bought a lovely subframe for my '96 Polo a while back and was really pleased with it. £25.00 delivered - how could you complain?

 

Enjoy the weather

Phil

A final update on this one. Spoke to the garage and they were very embarrassed and they do have the right tool to fit the bearing. The chap I spoke to who owns the garage who did the original job, before he knew the problem said he was known as Mr Wheel Bearing,, because he does nearly all of them. Irony indeed. Just a bad day.

The car sailed through the MOT and they set the tracking straight for me. All good  and they will be servicing and MOting my '96 plate Polo in a couple of weeks. Joy.

I have the new hub nut to put on and as I am rubbish at searching wondered if anyone would be kind enough to tel me the torque setting for this please? I assume torque plus 90 degrees?

Many thanks

Phil

 

Good news your original problem is sorted 

 

The 12 point (new)nut, tighten to 200Nm then slacken off 1 turn, then 50Nm then +45 deg  

OK - the nut has 2 non return tags on it. These grip on the splines of the drive shaft as it is done up like a ratchet, so I am not expecting to turn it back without the tags breaking off. Are you sure about the one turn back?

 

It is a 36mm 12 point nut.

 

Kind regards

Phil

 

 

Tighten 12-point nut to 200 Nm and then loosen one turn.

‒ → Tighten 12-point nut. Tightening torque: 50 Nm + turn 45°further ◆ To tighten 12-point nut we recommend the angle measuring wrench V.A.G 1756. That is taken from the dealer manual

I've not seen that 200Nm step on cars with this type of bearing and nut (Fabia Mk1 and Polo 9N); is that info definitely for the Fox, Nige?

My mistake as @Phil H mentioned his 96 plate 6N just before asking about the torque I assumed it was for the 6N forgetting the rest of the post was about the Fox

 

This is info for the Fox