A couple of weeks ago I was reversing out of a parking spot and put osf wheel up a kerb onto a piece of grass. About half a mile later abs and tc lights came on the off over about an hours time, when switching off the warning traction failure showed up on the dash. Nanocom shows no faults, can’t feel any play in any wheel bearings not sure what to try next.

If you've got, or had, an ABS fault, Traction Failure will come up on the dash when you switch off. Is it still doing it or has it now gone away? Chances are the ABS sensor on one wheel has moved and a light tap with a mallet to push it back in will be all that you need do. If it was a failed sensor, it would be detected during the self test when you first switch the ignition on and would also store a fault that the Nano could read.

I’ve only just run engine to get oil and water levels correct after doing work on it, I know abs light will not go out till I take it for a run, but tc is still lit and traction failure on dash when ign turned off. Is it worth monitoring nanocom to see if voltage to abs sensors changes when driven?. Might be in two weeks as away on Monday.
Thanks Richard

Yes, check the voltage, or wheel speed, with the Nanocom. They should all read exactly the same and as you start to creep forward, they should all start giving the same output at the same time. I've seen one where one sensor was sluggish and was slow to start giving an output which was showing the same fault as you have. A tap with a mallet was all that was needed.

I have a similar fault, which started about a year ago. ABS Fault and in a few seconds, Traction failure fault on the message centre.
15 seconds after I start the engine, and the Brake light goes out, and without moving, I get the TRACTION FAILURE message.
Once I start to drive, and get over about 5mph, I get ABS FAULT message.
I have never found any error codes stored in Nano?
Like Gilbert, who I believe has a similar issue?, I have been a lazy sod and not really tried to fix it......
Oh, TC and ABS seem to work when I tried them on a dirt lot!
Any clue?

That's right, I had similar on the Ascot, although it was giving a stored fault on the Nano. Fault was for one ABS sensor (RH Rear in my case) which when I tested it was open circuit. Changed that and everything back to normal. When the fault comes up as soon as you start the car and before moving, it is something failing the self test and, in most cases, it will be a faulty sensor, either open or short circuit.

That's what I suspected as well, but no faults logged, and for the brief time it lets me look at live values as I speed up, all sensors are returning data????
I will dig into it further.
I have checked both front sensors with an ohm meter and they look ok. The plastic surrounding the pins crumbled however, so I need to get some weather pack connectors and replace them.
Will check rears when it dries out this weekend.

Did a test with Nanocom, can’t understand how to put image on( I’m a bit dim when it comes to adding pictures), fr 2.33 fl 2.35 rr 2.35 rl 2.33 these are sensor voltage. Also got another set of voltage readings as fr 1.71 fl 2.98 rr 1.50 rl 2.60. Wheel speeds were shown as fr 4.0 fl 4.2 rr 4.3 rl 4.0. Do these mean anything?

Yes, you've got a problem. They should all be identical, especially the wheel speeds.

Can you give me an idea of where to look for the problem? As I said originally the abs tc lights only came on after putting osf wheel onto grass as coming out of a parking bay, is that just a coincidence?.
Thanks

If you can get the sensors out without breaking them, check the reluctor wheel to make sure none of them are gunked up with anything. If a couple of the grooves are full of muck, that will cause a lower than actual reading.

upnorth wrote:

Can you give me an idea of where to look for the problem? As I said originally the abs tc lights only came on after putting osf wheel onto grass as coming out of a parking bay, is that just a coincidence?.
Thanks

if you do a live drive test with diagnostic system on the wheel speed sensors
what ever MPH/KPH is showing the sensors should read the same so it doing 20mph the sensors should read 20mph to
hopes it makes sence

I have had two (of the many) ABS/Traction faults that have been ‘out of the ordinary’.

The first was a broken reluctor wheel on the hub. This was only diagnosed by jacking the car up and hand spinning the wheel and measuring the sensor output on an oscilloscope. There was still an output but it was ‘odd’ compared to the other three. Testing of the ABS sensor itself yielded nothing untoward - it’s resistance was the same as the others and it was giving an output. Looking down the ‘hole’ for the ‘odd’ output sensor and slowly rotating the hub did indeed show a broken reluctor ring. Hub replaced (pretty cheap and a lot easier than ‘sweating’ a replacement reluctor ring onto the hub) and peace and harmony was restored.

The second was flagged up as a normal sensor fault on NanoCom. However it’s supply voltage was normal and so was the speed output. However it’s resistance was a bit higher than ‘normal’ - not a lot but definitely higher than the others. Changed it and, again, all was well. I deduced from this that the POST by the Wabco unit tests the resistance of each sensor (current draw?) and if outside prescribed limits flags a fault.

Do those reading point to an obvious cause eg I believe that some problems can occur with corrosion on connections in the footwell area, this is a 1999 vehicle I also have a 2000 one not on the road that I could swap the ecu with, if that is possible and if that could help to identify the problem area. Only owned it for 6 months so don’t know anything much about it’s history, as I said originally this started when I put the osf wheel on a grass verge reversing out of a parking bay,just a coincidence I suppose.
Thanks

The only connection from the ABS system that goes through the footwell connector, is the feed to the OBD socket. The fact that you can connect to the ABS with diagnostics means that is OK. 99 and 2000 use the same Wabco D system so bits would be interchangeable.

Yesterday afternoon I was looking at the pictures of the Nanocom screen I had taken and noticed on one the battery was showing 11.5 v, knowing that low voltage can throw up problems I put it on charge and left it overnight. Voltage came up to 13.6v so decided to give it a run down a gravel lane to try brakes and see if I could feel abs working through brake pedal, I felt some pressure pushing back at pedal, well that’s what it felt like. Then all of a sudden abs and tc lights went off and when I turned ignition off traction control came back oh dashboard. Decided to go a couple of miles on road, no lights on startup but they came on during travel and then went off till I was driving back into garage with my foot slightly on the brakes then two beeps and abs and tc back on with traction failure coming on when ign turned off. I had Nanocom plugged in all the time, it worked at first then kept saying unable to communicate. Could battery getting weak be adding to or causing my problems, when Nanocom was working it showed battery at 13.51v whilst running I thought it should be over 14 v when running?.

13.5V is fine and it is the gearbox ECU that gets offended with low voltage, so unless you are getting gearbox fault on the dash, it isn't low voltage. ABS ECU will disconnect once you go over a certain speed so that is normal, you need to reboot and start again to get it to reconnect. If at any time you have had an ABS fault come up on the dash, you will always get a Traction Failure when you switch off. It sounds like you have an intermittent fault rather than something always there like a duff sensor.

I did get a gearbox fault on the dash the other day but only once, I think I will look at the socket that Nanocom plugs in to because it seems to be loose, I did not realise you had to re boot the system. I think I’ll swap the abs ecu to see if that changes things.

Well drove about 10 miles yesterday and no issues at all, I am going to keep using it and monitor the situation.
Thanks for all the replies, Richard

So after a couple of months using the p38 the fault is still occurring but only when I press the brake pedal and only when pressing the pedal when manoeuvring slowly. Last week I came to the conclusion the accumulator must be at fault and not holding pressure, I changed it yesterday went for a run pumped brake a lot when parking and no abs tc light. Started to drive out of garage today and it’s on again when touching brake pedal whilst manoeuvring, I was going to change abs ecu but didn’t because the problem only occurs when pressing brake pedal lightly. No faults showing on Nanocom, one thing I will say is when abs tc lights come on and traction failure comes up on dash when ign turned off both lights stay on on restart and go off together once speed up to about 5 mph but under normal working tc light goes out once system is up to pressure then abs light goes off at 5 mph like it should. Any more ideas?
Thanks Richard