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Traction Control Problem on D2


plantpot1961

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My problem is when I try to move off from stand still the traction control on the front left side kicks in. This is on the flat road.

In North Wales last week I had problems getting up a set of steps this resulted in me smashing the planet gears in the rear diff. Another diff now fitted and working fine. I went to take it for a test run now I have this other problem.

I checked for faults on NANOCOM but it was clear. Any Ideas as to what is causing this?

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does the traction control use the abs sensors, i know a lot of manufacturers do this... but not too sure on a d2.

does the abs light come on correctly if you hammer on the brakes? if it does use 'em, then i would check wires to the abs sensor, and check continuity through the sensor, between pins it should read something and not open circuit. measure it against another one on another corner and you can see if reads correct.

other than that, i don't know. also, maybe you can disconnect all abs sensors and see if this allows you to drive off correctly.

good luck

richard

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Hi Richard, Thanks for your reply. The TC is controlled by the ABS sensors. I have disconnected both front sensors and I have normal drive. I am guessing that if it was a faulty sensor the NANOCOM would register it?

I will strip out the sensor today and clean the matting face of it. Possibly I caused some damage to the sensor ring in the hub when I was trying to climb the step in Wales? This is inside a sealed hub. Before I splash out on a new hub (approx £200) It would be nice to know for sure. Thanks again..

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There are no rings on D2 like there are on D1 rear wheels or carved in the CV joint in front.

The bearing seals have some magnets embeded in them and that's how the signal is generated.

No need to clean the sensors. The only thing that can affect their performance (presuming the sensors are ok) is the bearings/seals being shot. Check for bearing play and noise on all wheels, by the way.

Questions:

1. What year is your D2 and what engine/trasmission does it have?

2. How did you get home from N Wales, by locking the center diff? Did you remove the rear half shafts for that, rear prop?

3. Does this occur at the first pull off of the day also? I.e. after the first start of the engine as well?

4. What about the ABS ot TC lights? Do they come on and when? If yes, give as many details as you can.

5. Between what speeds is this TC kicking in? My understanding is between 0 and ... ? 2nd, 3rd gears as well?

If you want to do some testing, see the last 2 paragraphs at http://forums.lr4x4.com/index.php?showtopic=31398&st=0&p=306383entry306383

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no worries, again i dont know much about disco 2's. but you could try to knock the sensor fully home after testing the sensors to see if they both read the same. if it is not the sensor itself, it could be too far from the magnets as mentioned. so try to drive it home more, carefully with a pair of pliers either side of the sensor and tap the pliers firmly but dont kick the tits out of it...

you never know...

richard

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I have checked for play in the wheel bearings but can’t feel any. The answer to the questions are;

1. It’s a 2003 with TD5 & manual transmission.

2. I was towed off the hill and then recovered by the RAC.

3. The problem occurs from standing still 1st gear, can’t get beyond 1st.It feels like its happening on the front left wheel.

4. The TC light comes on first then the ABS. After 10 metres the ABS stays on.

5. TC kicks in right away within 2 metres, as I move off. I have removed the ABS fuse and the car drives ok.

I thinks thats everything. Cheers and thank you.

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If the ABS stays on then the SLABS ecu sees a fault and declares it.

Try again a reading with Nanocom including the live data from the sensors while pulling off and driving on, according to the SLABS diagnostic functions you see here (the ABS related part, no need for the SLS part): http://web.nanocom.it/download/DIAGNOSTIC%20FUNCTIONS%20OF%20THE%20ABS-SLS%20SLABS%20DiscoveryII.pdf

P.S. Does Nanocom have the latest firmware? There were previous versions not having D2 SLABS capability.

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What about the speeds shown by each sensor, are they equal when you run at low speed when you say TC kicks in? Or a little above that speed to avoid the annoying TC.

I mean the live values you can pull with Nanocom stated in the link I gave previously:

Front right wheel speed(Km/h) - Front left wheel speed(Km/h) – Rear right wheel speed(Km/h) – Rear left

wheel speed(Km/h) –

These speed values must be 1.7-1.8Kmh when the car is stopped and increase when the speed is higher.

If they're not equal, give us some values.

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wow, tech stuff... nanotech fault displays might tell you, certainly they will if you have a problem with sensors or speeds.

as i said i dont know much about d2's, but if you can see the castlations are any of them damaged, if so that will certainly give you a speed difference.

i cant be too sure, but i guess the abs fault was caused when you removed the front sensor plugs and switched the car on, and they were cleared when you nanoteched it with the sensors connected.

anyway, good luck

richard

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Oh, then your Nanocom isn't of much help in this case, is it?

In theory you can suspend the vehicle, rotate the wheels by hand and read the sensor values. But you'll need to figure out a way to give the wheels the same rpm somehow, one at a time.

Another way is for someone to tow you with a tow bar and maybe a helper to drive the vehicle and you keep an eye on the figures. Or find an inclined not so busy road to test, helper recommended. Mind you won't have brake and steering assistance and you'll have to be very careful.

Or if you have access to a rolling road you can use that.

If none of the above looks appealing to you then take your Nanocom with you at all times and the first time the ABS light comes on and stays that way, pull over, stall the engine (brake hard, 1st gear and let go the clutch pedal as you would normally pull off), i.e without touching the ignition key, and try reading the fault with Nanocom.

Or you can go to a garage that has the proper equipment for some live sensor readings or ecu faults.

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If none of the above looks appealing to you then take your Nanocom with you at all times and the first time the ABS light comes on and stays that way, pull over, stall the engine (brake hard, 1st gear and let go the clutch pedal as you would normally pull off), i.e without touching the ignition key, and try reading the fault with Nanocom.

Or you can go to a garage that has the proper equipment for some live sensor readings or ecu faults.

Because of the original problem I can't drive anywhere. TC won't let me.

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not 100% sure, so you might be wasting your time, however you can download obdii and all that from internet and some nano's can be software updated, also, there are some obdii that you can run as virtual nano's from a laptop, as long as you have a connector the the diagnostic port. everyone has lappy's these days, and i'm guessing even landy owners like you and me have 'em too. so if you do, download some obdii software and use your lappy to do this.

make sure all the mechanical suggestions(by me) are done first unless they dont apply to the d2's. then go on with the nano stuff. as you may well be missing the obvious and going down the tech route for no reason.

anyway, there you go. can't really help you with anything else, so i will watch this thread for now and let the rest of the forum bring to bare their views and advice.

richard

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These OBD things don't work on LRs. You can pull some general fault codes on V8 ecus and that's about it.

Because of the original problem I can't drive anywhere. TC won't let me.

For some reason, I thought you could drive the vehicle throughout the 1st gear at least but it seems the ETC brakes one wheel very hard. This means there's a big difference in speeds ECU thinks the wheels spin at.

I wonder if you can trick the ABS ecu not to get into TC mode by keeping the brake pedal switch engaged. This would be a way to disable TC without removing/disconnecting other bits that would certainly induce an ABS fault and would allow you to drive the vehicle.

Try lifting the front wheels, one at a time, rotate them by hand or whatever other means you can think of, say once per second and see what you get from Nanocom. Once per second, presuming the D2 is on standard tyres, means aprox 8.3 km/h.

You can also disconnect the sensors from both front wheels (connector are in the engine bay, follow their wires) and measure/compare their outputs like I suggested in link I gave you in my 1st reply.

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Gents thanks for all your help so far. I am stuck now as I'm working tomorrow 7am to 7pm, same for Thurs. If I get chance in the evening I will try your advice. If not I'm off on Fri will do it then. Thanks again I really do appriecate it. Cheers. Mark. Watch this space.....

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Okay

A simpletons question amongst all this technical stuff. My disco2 is new (to me) I have never driven with TC before and havent yet been offroad apart from onto the odd muddy verge. Is the TC supposed to make that awful noise or have I a problem with it?

Thanks

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The sensor rings are inside the hubs as you say,your car is suffering from faulty software in the SLABS ecu - a common fault rectified by the fitment of the upgraded version SRD500070 - thats from memory so you need to check its right with your dealer.The DII uses the same type of toothed ring as earlier cars,(D1,RR classic etc)its just placed inside the hube with the non serviceable bearings.Normally the problem with them is a weak signal from a slightly wide air gap/worn bearings.This failure is not as common but is far from unknown - the last one I did would put the TC on at 65mph on a dry road.

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The sensor rings are inside the hubs as you say,your car is suffering from faulty software in the SLABS ecu - a common fault rectified by the fitment of the upgraded version SRD500070 - thats from memory so you need to check its right with your dealer.The DII uses the same type of toothed ring as earlier cars,(D1,RR classic etc)its just placed inside the hube with the non serviceable bearings.Normally the problem with them is a weak signal from a slightly wide air gap/worn bearings.This failure is not as common but is far from unknown - the last one I did would put the TC on at 65mph on a dry road.

My car is 2003 whould it's SLABS be fairly upto date. also I have changed both front hubs so it rules them out. I will now try some of your other suggestions thanks to CipX2. Cheers Mark

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Cant remember,they used to be £180 odd plus Vat,but they have gone up.(Typical LR ! )I fitted one about a month ago,I'll look up the invoice when I get back to work.Think the retail is around £240+Vat.

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Well, replaced the SLABS ECU but the problem still exist. I have noticed that when I have run it with this TC problem 3 of the 4 brake discs are hot. The rear off side disc is cold, so the brake is not being applied to this. Other than this it's back to sq 1.

I've now lost the will to live and thinking of buying a BMW....... :o

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