Discovery 2 TC

[Yakuza]

I am having an problem with my D2 when i am driving on Tarmac or gravel and hit an big hole or some corrugation the Traction control kicks in an slows the car down, its bad when i am driving on the road and does it,

I changed the rear right Hub and checked for codes using Nanocom and nothing comes up.

Also i dont have an lights on the dash that come up

Any help will be appreciated

Thanks

[sierrafery]

There's a missbalance between sensor signals, it can happen even if you mix different brand sensors cos admitted resistance of a sensor is between 950-1100 ohm and if one is at the lower limit and others at higher or vice-versa they'll past the system self test cos the stationary output is between 2.0 - 2.4V so no fault codes but in movement at the same wheel speed one input is higher or lower and the system interprets it as wheel slip

did you fit genuine or branded hub? if not did you count the teeth of the reluctor ring? cos some cheap chinese ones have 55 instead of 60 and that can cause issues too

you need nanocom plugged in to see which sensor is giving different readings

untill you fix it if it's very annoying you can remove the ABS pump relay(R10) then you'll get the 3 amigos and no ABS/TC activity... just be aware that the brakes will work normally like on a non-ABS vehicle which might not be bad cos even the ABS can be erratic due to this missbalance and then it can make you trouble rather than help you

[Yakuza]

OK, well the brand i bought is Optimal An german brand, and this is an dumb question but how do i count the rings? As i only see the spline on the hub?

[sierrafery]

If it's german product dont bother to count(you can count only through the sensor's hole) ... might be the sensor's resistance different...can't you fit the sensor from your removed hub for test?

a nanocom would be great help if you can find somebody close to you to help

[Yakuza]

I got an nanocom and here is what i found after an little test drive just now.

Voltage
Car on idle (standing still)
Front Front 002.19
Front Left 002.19
Rear Left 002.17
Rear Right 002.17

Car Moving
Front Front 002.21
Front Left 002.19
Rear Right 002.17
Rear Left 002.23

Wheel Speed (KMH)
Front Front 0008.2
Front Left 0008.2
Rear Right 0008.2
Rear Left 0007.5 ( HERE is the one i change to there German Brand Hub)

[sierrafery]

Put back the old sensor and see then... if it's the same it means that the german hub might have wrong number of teeth, might be a german hub made in china:cool:

[Yakuza]

And is it ok to unplug and unscrew the sensor and swap around?

Coz i read that it upsets it and its not good?

[sierrafery]

you can swap sensors either way as you wish, no problems with that

[Yakuza]

Well i counted the teeth is it 55 :( So I have to get an 60 tooth one,

Idk if this will help i bought 2 hubs including the one i change so would it be of any help to put that one on so the rear is the same speed but slower to the front?

[geordiepride]

very intresting read
I have just purchased 2 front hubs for mine waiting for them to arrive

[sierrafery]

Well i counted the teeth is it 55 :( So I have to get an 60 tooth one,

Idk if this will help i bought 2 hubs including the one i change so would it be of any help to put that one on so the rear is the same speed but slower to the front?

I doubt that would be good cos the TC works in axle pairs too so i might put brakes on both wheels of that axle to equalise inputs with the other axle also the system was calibrated from factory for 60 teeth hubs... eventually put all to be the same 55 if it's better for you then the only issue can be with the speedometer reading

[Yakuza]

Ill Try to buy 60 teeth hubs and replace it again

[justinc]

I've also had this issue once before. However the hub wasn't replaced, i had just fitted a long sensor from the hub all the way to the ECU. I always solder the new sensor wires due to the fact it is easier for me than disassembling the plug and fitting new pins under the dash...
The problem in this case which took me a while to trace the fault was that even with both wires insulated and seperated there was a sharp spike of solder pushing through one insulated connection and intermittently contacting the other wire through its insulation. The spike was needle sharp and I'm not sure how I managed not to cut myself on it while taping it up.

Basically the signal from the wheel sensor was telling the ecu a wheel was locking. No fault codes as it was doing its thing fine😮😕

Jc

[LyleC]

Hope you got is sorted Yakuza.

After reading all the posts on this site that I can on this and similar issues, I am still puzzled.
I have had the TC operate for seemingly no reason also.
However I read that individual wheels should only be braked by TC when under 50 km/h and 50-100 km/h only front / rear wheel pairs should be TC braked.
Not the source I read, but close: "This system will operate fully up to a speed of 50 km/h (31.25 mph) and some functions are active up to speeds of 100 km/h (62.5 mph)."
I have experienced TC braking (TC light indicating operation) at about 80 km/h recently.
No recent hub/sensor changes.

This made me think the SLABS unit was at fault. Why else would this happen unless multiple sensors / signals are giving the wrong speed to the SLABS and a faster speed to the speedo?
OK maybe one sensor momentarily give zero speed and the average falls below 50 km/h for TC to operate and the speedo is slow to react - but that sounds a bit unlikely??
Anyway I pulled the ABS fuse and drove home. (as a side comment, driving home the HDC green light was on also but occasionally this would go out and the speedo would go to zero at the same time. At the time I took this to confirm the SLABS as being the problem.)
I went to a local land rover 'expert', who had not seen this problem before.
I have also talked to M R Automotive who say they have not sold a SLABS since 2011. So if it was the SLABS then it would be unusual.
Anyway the local mechanic did the usual checks - no faults found other than from pulling the fuse, no bad sensors. He then swapped the SLABS with another he had.
My SLABS was an SRD000070 (original I believe) and the mechanic installed one is SRD000170.
His test drive confirmed that TC was still kicking in (not sure of speed)
So I have now pulled the ABS relay so my wife who normally drives the D2 to work, doesn't end up TC swerved across the centre line.
This relay out gives the three amigos plus the brake warning light, which is also not a long term solution.

So at this stage I am just going to have to go through all the other fixes that I have seen on this site:
try to invoke the problem a few more times to check scenario, tyre pressures, suspension balance, Sensor fitment, sensor cable integrity, hub reluctor tooth count, ......

Any thoughts??

[Pedro_The_Swift]

"some functions work up to 100kph"

thats nice,, I'd expect the "other" half of Traction Control (ABS) to work at any speed--- its all the same sensors.

in fact,, at road speeds it would be the ABS doing the hard yards,, ( modulator still felt through floor) though an unintended wheel "lockup" would be dramatic!

Hmmm...

[Kaaaiju]

Yeah i have got it sorted, since that fix never had that TC issue since,

Rang the person up in the UK and sent it back for an refund and correct hub, All good

[LyleC]

Hope you got is sorted Yakuza.

After reading all the posts on this site that I can on this and similar issues, I am still puzzled.
I have had the TC operate for seemingly no reason also.
However I read that individual wheels should only be braked by TC when under 50 km/h and 50-100 km/h only front / rear wheel pairs should be TC braked.
Not the source I read, but close: "This system will operate fully up to a speed of 50 km/h (31.25 mph) and some functions are active up to speeds of 100 km/h (62.5 mph)."
I have experienced TC braking (TC light indicating operation) at about 80 km/h recently.
No recent hub/sensor changes.

This made me think the SLABS unit was at fault. Why else would this happen unless multiple sensors / signals are giving the wrong speed to the SLABS and a faster speed to the speedo?
OK maybe one sensor momentarily give zero speed and the average falls below 50 km/h for TC to operate and the speedo is slow to react - but that sounds a bit unlikely??
Anyway I pulled the ABS fuse and drove home. (as a side comment, driving home the HDC green light was on also but occasionally this would go out and the speedo would go to zero at the same time. At the time I took this to confirm the SLABS as being the problem.)
I went to a local land rover 'expert', who had not seen this problem before.
I have also talked to M R Automotive who say they have not sold a SLABS since 2011. So if it was the SLABS then it would be unusual.
Anyway the local mechanic did the usual checks - no faults found other than from pulling the fuse, no bad sensors. He then swapped the SLABS with another he had.
My SLABS was an SRD000070 (original I believe) and the mechanic installed one is SRD000170.
His test drive confirmed that TC was still kicking in (not sure of speed)
So I have now pulled the ABS relay so my wife who normally drives the D2 to work, doesn't end up TC swerved across the centre line.
This relay out gives the three amigos plus the brake warning light, which is also not a long term solution.

So at this stage I am just going to have to go through all the other fixes that I have seen on this site:
try to invoke the problem a few more times to check scenario, tyre pressures, suspension balance, Sensor fitment, sensor cable integrity, hub reluctor tooth count, ......

Any thoughts??

Update:
With ABS relay refitted: no lights but sometimes three chimes at start-up, which the manual tells me is ABS warning.
With my Nanocom connected, only fault found was from removing ABS relay. This cleared and no faults remain, but chimes still sound at start-up sometimes.
Checked tyres, suspension sitting evenly, Nanocom gave normal standing reading for sensors. Attempted to cause TC operation by dropping front R tyre pressure and driving in circles full left turn (to get front R tyre tuning faster than average speed), but this obviously didn't deviate enough to get TC working.
So drove up one of two ramps I have. Ramp is about wheel base length and rises to about 1 metre high. This gets the disco cross axled and spinning wheels. TC light comes on (but didn't really seem to do much).
Doing this I also proved TC operation with diff lock and without, so the SRD000170 SLABS must be from a D2A? Mine is a 2000 model.
I still need to do a straight ahead check of wheel speeds all matching - just to prove all reluctor rings are the same.

I would say the the replacement SLABS module did the trick, except am getting ABS three warning chimes at start-up inconsistently but no faults on nanocom.

Any more thoughts??
Cheers,
Lyle

[sierrafery]

.....
I would say the the replacement SLABS module did the trick, except am getting ABS three warning chimes at start-up inconsistently but no faults on nanocom.
....
You'll hear those chimes every time if you wait untill the system self check is completed ... that's how the system tells you it's over, that's the normal behaviour of facelift SLABS ECUs and no worries as long as no warning lights are on

from D2a owner's handbook:

ABS warningIf a fault with the anti-lock braking system is
detected, a warning will chime three times and
the warning light will be illuminated. You may
continue driving, but should understand that
full ABS control may not be available. Consult
your Land Rover Dealer/Authorised Repairer at
the earliest opportunity.

Three warnings may also be heard during
engine start-up as part of the ABS system
self-checks. This is normal unless the ABS
warning light stays illuminated after the engine
is running.

[LyleC]

Thanks for the helpful reply sierrafery.

I'll have to try being a little more patient.
That also reminds me reading something about some checks are only performed if the vehicle goes above X km/h during the previous ignition cycle.
Must go find that detail again.
Cheers,

[Tins]

You have probably done yourself a favour if your car has a CDL, as the D2A SLABS have a less aggressive TC map to work with CDL engagement. Well. that's my understanding of it.

[Bohica]

You'll hear those chimes every time if you wait untill the system self check is completed ... that's how the system tells you it's over, that's the normal behaviour of facelift SLABS ECUs and no worries as long as no warning lights are on

from D2a owner's handbook:

And if you don't hear those chimes? I don't.

[LyleC]

Further update on the traction control. I took the D2 up waterfall creek road (good steep rocky track at Mount Barney) and traction control did all the right things, and even tried out the hill decent control on the way down.
All worked as expected and no unwanted three amigos, so I think this confirms as far as possible that the new SLABS has done the trick.

The three chimes sound at start up if I wait for all the check lights to go out.
This is with the SRD000170 SLABS now installed, but didn't ever happen with original SRD000070 SLABS.

Maybe your chime sounder is tired Bohica? :)

[Bohica]

My chime sounder is not tired. It keeps sounding the three amigos.

[RANDLOVER]

Further update on the traction control. I took the D2 up waterfall creek road (good steep rocky track at Mount Barney) and traction control did all the right things, and even tried out the hill decent control on the way down.
All worked as expected and no unwanted three amigos, so I think this confirms as far as possible that the new SLABS has done the trick.

The three chimes sound at start up if I wait for all the check lights to go out.
This is with the SRD000170 SLABS now installed, but didn't ever happen with original SRD000070 SLABS.

Maybe your chime sounder is tired Bohica? :)

I think you've fixed it, as I've been up that track (thru the farmer's gate to the Portals IIRC) in my D3 and it brought the TC on a couple of times.