Have you had the fault code cleared electronically.

 

The garage that fitted the hub said they weren't able to clear the fault indicated on the dashboard

 

Did they clear it and it came back or was the equipment they had not up to the task, unless its cleared the light will stay on.

 

And by the way, there is definitely a problem with the ABS coming on - sometimes when I drive off the fault isn't there but comes on shortly after, sometimes the lights stay off so no fault but more than ever now the ABS lights come on and stay on AND sometimes there's a few seconds of 'grinding' noises and you can feel the ABS actually operating or 'kicking in' and even when I brake on a steady, dry, flat surface it operates on the odd occasion. Can this still be faulty plugs/wiring?

 

I can't answer for what equipment they used but they're an official M.O.T. approved garage so I expect they know what they're doing and are using the right equipment. Can you help with a wiring diagram?.

 

Yes, i will look through it and post shortly...

 

Ok, From the sensor plug you have 2 wires running up through the inner wing, just behind the inner wing located in the engine bay is another 2 pin plug, check this plug for corrosion, the wires should be Red in Pin 1 and Yellow in pin 2, these then run around the engine bay to a large multi plug thats fixed to the top of the inner wing on the passenger side, sandwiched between the fuse box and wing, the Yellow wire enters this plug at Pin 10 and the Red at Pin 9.
From the plug the Red turns to Blue/Red and goes to Pin 5 of the ABS pump plug. The Yellow turns to Brown/Red and goes down to Pin 6 of the ABS plug.
You should be able to do some continuity test with this info.

 

Apologies for the late response - I'm still trying to fathom this out and have only just seen your reply today! Got no notification that there'd been an answer, never mind 2! I appreciate your knowledge and will trace these wires out. Thank you, and I hope you get notification I've replied!

Cheers.

 

It will be the plug from the new bearing/hub assembly not fitting in tightly enough. A cable tie to pull it on will sort it. Ive had to do it many times myself with aftermarket hubs on the Astras & Vectras.

 

Thanks and please see my reply to the other person, andy!, above. I appreciate this and will check this out at the weekend - no football so I'll have time ;-)

 

Sounds more like a cracked ring/damaged magnet based on that description

 

Do you mean on one of the ABS units - the offside one is new and this was happening before that was changed and it was their diagnostics that said it was that one that was faulty.

 

Yes. In older cars you'd have a cog, usually on the end of the driveshaft, for the ABS sensor to pick up as the wheel spun round. When this cog (or ABS ring) cracked it created a larger gap than that between the cog teeth. When this happened it would confuse the ABS into thinking the wheel had locked up causing it to kick in early, often leaving you without much brakes. On newer cars like your Astra the cog is replaced by a magnet built into the hub but the principle is the same. If the magnet is damaged then it could give the same symptoms as a cracked cog.

I wouldn't be happy about paying for the work you've had done that has achieved nothing. Do you know if the garage simply looked at the fault codes before assuming it was the sensor or did they take a look at the readings etc.? It could be that the new unit is faulty

 

Yes. In older cars you'd have a cog, usually on the end of the driveshaft, for the ABS sensor to pick up as the wheel spun round. When this cog (or ABS ring) cracked it created a larger gap than that between the cog teeth. When this happened it would confuse the ABS into thinking the wheel had locked up causing it to kick in early, often leaving you without much brakes. On newer cars like your Astra the cog is replaced by a magnet built into the hub but the principle is the same. If the magnet is damaged then it could give the same symptoms as a cracked cog.

I wouldn't be happy about paying for the work you've had done that has achieved nothing. Do you know if the garage simply looked at the fault codes before assuming it was the sensor or did they take a look at the readings etc.? It could be that the new unit is faulty

I don't know exactly what they did unfortunately, I trusted them to do it as we tend to do with garages. I bought the parts that they recommended and paid labour costs for the half day. I would fit a nearside unit but I don't know if that's the fault or elsewhere like wiring or a control unit and I don't know how difficult it is to replace but it doesn't look easy. The fault didn't change particularly after this replacement but is it likely to have the same fault on a new unit?

 

What exactly was changed? Half a days labour seems extreme

I wouldn't be playing guesswork with these sorts of things. Personally I would be looking at the fault codes then taking the car a run with the computer plugged in to see what each sensor is reading. That would then point me to which corner was causing the problem so I could check the wiring from there

 

Thanks, one sort of final question here - would you suggest using one of these hand held diagnostic units for this? They aren't expensive and seem to be able to do the job at least in reading the problem.

Thank you very much for your help, I do appreciate it.

 

Only thing I would recommend is op-com (bout £30) or a tech 2 if you've got a spare 2k lying around

 

Well the cable tie trick didn't do anything although the connection from the new unit to the existing harness mounted on the wheel housing is not a great connection. Possibly the retainer clip was broke when it was fitted as it wasn't held in at all - but it's tight and secure now. I'd like to do continuity tests from wheel to the connection unit next so I'll update when I've been able to get to all of it

 

Only thing I would recommend is op-com (bout £30) or a tech 2 if you've got a spare 2k lying around

Bought the OBD2 device and it shows no connection/data coming from the front right ABS sensor. As above, need connecting diagrams although I have cleaned and checked as much as I can there is one glaring possibility to me. When I bought the car I had a constant fault - nearside headlamp failure. Turned out to be a broken wire in the cable harness connecting to the ECU/fuse box. These ABS cables join that harness at exactly that same point to get to their connector points as above so I might just link out that section, which is what I did for the headlght problem. Might be a coincidence but... ...watch this space, if you can be bothered!

 

Certainly worth checking out. I'm assuming as soon as you clear the code it comes back?

 

Strangely enough the only fault code I get is 0597 which means the thermostat is open. I can clear this but I think it returns. I have the brake and ABS orange lights lit up on the dash but when I connect the computer it shows no data or output from the front, right ABS unit, as detailed in earlier posts - I did clear ALL error codes anyway but I have never seen an error code relating to an ABS fault.

 

You say you have no data from the front right? What exactly do you mean by this. I thought you meant that the front right sensor wasn't giving you a reading?

 

Yes that's right. The software shows readings from all 4 wheels when moving except there's nothing coming from front right. It'll most likely be the wiring loom where I've mentioned as there are no other areas or connections that may be a problem as far as I can see. After this the 4 wires disappear into the car and without a wiring diagram I'm unlikely to get any further.

 

So you should be betting a fault code from the ABS ECU then?

@andyl is correct about the wiring. A wiring daigram doesn't show you where the wires go through the car. Only what colour wires go to what component and which pin no's they end up in. What you need to do is fined the pin where these ASB wires go to in the ABS ECU then check between there and the plug for the sensor for continuity and resistance

 

The wires will go to the ABS ecu/pump which is below the coolant header tank.

 

It's where they end up that matters as that's where I need to do continuity checks to/from and where they start is at the ABS unit of course. Without a wiring diagram I'm going off information that doesn't appear to completely match the wiring in the car so how can I check it? A wiring diagram will show the colours of the wires when they start and any changes so the ABS ECU connectors on the wiring diagram would show this - that's the information I may ultimately need. So far I know they go to this large plug stuck to the chassis and are brown/red and blue/red from the unit to here. I will check continuity to this point and believe the fault will lie in this mass of cables below the fusebox in the engine compartment. If not then, what?

I only did a pedal check for codes so far and that comes up with 0597 ONLY and I can clear this but it returns. This signifies an open thermostat which in theory keeps the engine cooler and I've ordered a thermostat to replace this one. I will check on my laptop this morning for any other information/codes.

Cheers.

 

Pedal test only shows up engine ECU codes. I don't have a wiring diagram for you but I wouldn't expect the wires to change colour between the ABS plug and ECU.

Let us know what fault codes you get from the ABS

 

Just got back in and just for the record...

...it WAS the blue/red wire somewhere between the entry into the engine compartment on the driver's and that impossible to see/reach/over large/pointless connector plug on the passenger side. I have simply scotch-locked a blue wire at either end and it works!!! I was convinced, once I knew it was a connection problem, that it was where I had the headlight problem - continuity tests showed a break in that cable. I still haven't checked for fault codes on my laptop but I cleared errors the other day, will check later. I am dearly tempted to return to the garage that fitted the ABS unit and ask for my money back!

Thanks for your help. Even being able to discuss and hear explanations helps, makes you consider alternatives etc. I'd love to know the sense behind that connector plug though - it could house about 30 or more connections but only the 4 ABS cables go in and come out to continue the same colour to the ECU and they go the longest way round in doing that.

 

Glad it's sorted

 

Yeah, me too. It's been about 6 months since it first flashed on. About 2 months ago it cost me £100 at a garage as I've said AND finally fixed with a piece of mains cable. Thanks for your help lads

 

Sometimes easier running a new wire than trying to fix the broken bit. The usially the hard part is finding the thing!