defender 2006 traction control not working.

[benrover]

I've recently purchased my Defender and love it, I have done a lot 4WD tracks now and have come to conclusion that TC is not working while ABS works on both dirt and tar with no issue!

When I'm crossed up tc blinks on the dash like expected but doesn't seem to apply the brakes on any tyre, had a mate look while I gave it a boot in low 1,2,3 and 4 with the CDL engaged - nothing, no sounds, no dying in the revs, it's just spun the two wheels that had no traction and went no where!

I the only thing I can find manual-wise is http://www.landroverweb.com/Pdf-files/Defender%20MY2002%20Wiring%20Diagram.pdf pg.40-41 ABS

Does anyone know where or what I should look at to fix this issue? - It's been scanned and doesn't have any fault codes.

[djam1]

Put a Nanocom on it and see if the ABS ecu has errors
When crossaxled and you get the flash of the light on the dash do you get a growl from the pump?
You can test the pump from a Nanocom from memory if ABS is working then the system is likely sound
Do you have 2 lights lit on the dash when you start the car one goes out after a short time the other when you reach 7 kmh

[jbe]

As Djam1 said, put a Nanocom on to see if you get any ABS related errors. The way the ABS is designed, I can't see how the ABS can work and the TC not.

[PhilipA]

I must say that my first thought on reading this thread was that The OP may have brake pads that need time to warm like Bendix, or that his braking system has not been bled correctly for a long time.
I have seen a video of a Defender with ABS going across muddy wombat holes and the Traction control does work if working properly.

In my D2 I fitted Lucas pads as they are soft like OE and regularly(well every 2years) bleed my brakes.

If the discs get wet say crossing a river, it takes a few seconds for the discs to dry , then away you go.
My ABS pumps even when I cross a gutter!

Does a Defender have Hill Descent control? If it has then a way to check is get on steep downhill and put into low and away you go.

Regards Philip A
I also exercise my Traction control by using HDC every month or so in my street.

[djam1]

Even old brake fluid can effect it but if the pump isn’t engaging then there is an issue
Nanocom should give a code

[benrover]

OK so I have been to the LR specialist, there is no errors on the diagnostics, the return pump turns on with the tool.

I have put the car on stands so that no wheel was touching the ground and with the engine running check each wheel, the tc lights comes on when each wheel is turned but does not apply the brakes during a "slip condition - tc engagement" !

Keep in mind abs works as expected!

What should I check next? I don't want to pay 3.5K for a new ABS modulator!!

[djam1]

This traction control only works across the axle not diagonally or end to end.
If you jack up the front right hand and the rear left hand tyres and try to drive off does the pump cut in?
You will need to give it a few revs
In this situation the traction control will attempt to put on the front right hand and rear left hand brakes on
As mentioned by Phillip if your pads need to warm up the effectiveness at this stage will be limited
The modulators don't need to be replaced they can be fixed for under 1/3rd of the cost of a new one
Your all 4 wheels off the ground scenario proves little as you wont spin the wheel fast enough to get the brakes to engage

[jbe]

OK, this is getting beyond my expertise with the Wabco ABS (which is limited).

To my knowledge, none of the Td5 defenders has hill descent control, but I could be wrong.

Did the LR specialist comment on your problem at all? Have you googled for similar issues?

I am fairly sure that an ABS pump, modulator or sensor error would throw up a fault code.

What makes you confident that the ABS actually works apart form the dash light.

I am not sure if the car has to drive for a certain distance for the TC to work, i.e. all four wheels spinning at the same peed.

[djam1]

No TD5 Defenders had HDC the system is the same as the early Puma

[benrover]

from the landy specialist...

***** jack up the car so no wheel touching ground and spin each wheel individually!
if the brakes are applied to that wheel when spun tc is working on THAT WHEEL!

Yeah thats right no HDC with the 2006 TD5 defender!

Yes the pump(ABS RETURN PUMP - seen in the diagram above) turns on as I did mention in my post, you can feel it when putting you hand on the ABS unit. No noise it's really quite, as far as I can tell it the computers see wheel slip and knows it's happing just doesn't apply the brakes..

does this mean the pump's seals are shot??? can someone please provide a schematic to the ABS system ?

[djam1]

If the ABS pump is working properly it’s quite noisy if you jam on the brakes on with 2 wheels on the dirt does the ABS violently kick the brake pedal
You said in your previous post that the lights come on but didn’t mention the very noisy pump sounds like it is working maybe with a pump pressure issue or it’s partially seized
I have the Wabco D manual will try to send it to you
Jobson auto electrics in Carlton Melbourne can overhaul the unit for you

[benrover]

If the ABS pump is working properly it’s quite noisy if you jam on the brakes on with 2 wheels on the dirt does the ABS violently kick the brake pedal
You said in your previous post that the lights come on but didn’t mention the very noisy pump sounds like it is working maybe with a pump pressure issue or it’s partially seized
I have the Wabco D manual will try to send it to you
Jobson auto electrics in Carlton Melbourne can overhaul the unit for you

Yes lights are on and working as expected! The ABS pump is dead quite, can only tell it's running because I put my hand on it when a power bleed was done with diagnostic tool and when I activated tc by turning one the wheels. I woudn't say the ABS threw my foot of the pedal but the wheels don't lock up on tar or dirt and it feels like ABS is working.

I think the brake pedal actually goes further to the floor when ABS kicks in still no noise either, Im about to put my new steering arm on so once thats done I'll take it for a drive and double check thats the case also I'll pull the ABS fuse too and see if the brakes will lock up and report back.

[benrover]

I think the brake pedal actually goes further to the floor when ABS kicks in still no noise either, Im about to put my new steering arm on so once thats done I'll take it for a drive and double check thats the case also I'll pull the ABS fuse too and see if the brakes will lock up and report back.


No noise and the ABS is definitely stopping the wheels from locking, I hit the brakes with and without the fuse to check it. The pedal just feels like clicking under my foot not a big kick.

[jbe]

Might be worth checking the ABS relay. If the contacts are burnt out you can have all sort of weird issues.

[benrover]

After reading the Wabco manual djam1 sent me Dropbox - Wabco D.pdf (https://www.dropbox.com/s/2czw0m9lp2z5987/Wabco%20D.pdf'dl=0), I am sure that the pump is the problem!

For anyone who is interested it seems that the ABS can still function even if the return pump is not working, you can see this in the hydraulic schematics, ABS mealy attempts to limit the pressure on each brake by shutting the inlet valve once it detects traction lost on that wheel, it will hold both the inlet/outlet values close for a small time then if the foot is still on the brake and wheels are still de-accelerating it will open the outlet value allowing the fluid to flow through the expander chamber and is pumped into through the suction and pressure valve, then, back into the foot pedals line to increase the pressure at the brake .

I'm willing to bet my bottom dollar that the fact my pedal goes in a smig and not kicking out is proof that this pump has failed..

Has anyone pulled the modulator apart before? is there a pull done schematic available? - I use to rebuild hydraulic rams so i'm sure I can mange to replace some pump seals!

Or otherwise what about just connecting up four switches to each inlet valve, you could manually shut off the wheels that are aren't spinning and force the power to go to wheels with traction, just depressing the brake will make it work!! Thoughts? anyone does this?

[djam1]

I would be concerned about the legalities as it relates to the brakes
Can imagine the weeping and gnashing of teeth if it caused an accident

Ring Ian at Jobsons he fixed mine not related or associated just a customer

European Car Specialist Melbourne, Melbourne CDB, Carlton, Fitzroy | Jobson Electronics (https://www.jobsonelectronics.com)

[djam1]

Actually if it is just the pump I think you can rob one from a D2 Modulator as they are very similar, I recall someone doing this in the past

[jbe]

My ABS pump on a 2005 Defender Td5 died a bit more than a year ago. I had a look at swapping it with a complete D2 modulator unit, but was not comfortable with the fact that the outlet ports are labelled in a different order to the Defender. Therefore, an outright swap with a D2 unit was not an option for me. Graeme Cooper here in Sydney split the modulator and used a good pump from a D2 unit and used my defender valve body. Their head mechanic told me that it was not unusual on Defenders due the positioning of the modulator in the engine bay.
Cost me much less than a new unit and it still works fine. If I remember this correctly, my dead ABS pump logged a fault code though.

[benrover]

That sound like the go, I'll ring around for one tomorrow

any idea what a D2 module is worth? do people split them often?

Cheers Im Brisbane based if anyone here know somewhere to call it would be great.

[benrover]

My ABS pump on a 2005 Defender Td5 died a bit more than a year ago. I had a look at swapping it with a complete D2 modulator unit, but was not comfortable with the fact that the outlet ports are labelled in a different order to the Defender. Therefore, an outright swap with a D2 unit was not an option for me. Graeme Cooper here in Sydney split the modulator and used a good pump from a D2 unit and used my defender valve body. Their head mechanic told me that it was not unusual on Defenders due the positioning of the modulator in the engine bay.
Cost me much less than a new unit and it still works fine. If I remember this correctly, my dead ABS pump logged a fault code though.

do you remember how much it was?

[jbe]

do you remember how much it was?

$1200 drive in - drive out. From memory, they told me that there was a risk of damaging the solenoid (i. e. rendering the valve unit useless), but I was happy to take the risk.

[benrover]

Thanks for all your help people, I'll be pulling the unit apart this afternoon, and will find out whats happening.. if you interested keep checking back I'll post some photos of what I find.

To sum up, when my pump turns on it's dead quite, can only tell it's on with a hand on the unit, I have since watched few youtube vids of a power bleed, what a difference in noise - something sus there!

According to this PDF I found (hummers have the same unit) Dropbox - absmod.pdf (https://www.dropbox.com/s/83lbqbgvsqlzhdz/absmod.pdf'dl=0) - it shows there is an off-centred bearing that depresses some "plungers" while rotating in the pump body I suspect that this bearing is either missing (maybe from factory), fallen apart or the shaft has sheared, as there is no pressure in in the brakes from TC no kicking from ABS and no pump noise, I wouldn't expect both "plunger" seals to fail at the same time and even then there would still be some audible noise from the module if they were being contacted by the bearing.

Does this sound like a reasonable assumption and possible cause of my issue?

Also just a heads up I found a post claiming the OP fitted a D2 modulator to his defender - the d2 unit has different ports but he just tried connect it as if it was a defender unit and it works perfectly each wheel being braked correctly see the post for more info, he posted back a year later saying he's had no issues to date - Land Rover Defender TD5 ABS Modulator | LandyZone - Land Rover Forum (https://www.landyzone.co.uk/land-rover/land-rover-defender-td5-abs-modulator.227540/)

[benrover]

Thanks for the help people!

Just watched some power bleeds online - wow what a noise.. after reading this PDF Dropbox - absmod.pdf (https://www.dropbox.com/s/83lbqbgvsqlzhdz/absmod.pdf'dl=0) where you can see the pumps guts. I think the bearing that contacts the "plungers" has fallen apart or was never there.. 😂 which in turn causes a pressure problem.

Anyone know the bearing size?

[djam1]

The next joy you are going to have is getting it out of the car
It is possible you can take it out the top but it is difficult

[benrover]

The next joy you are going to have is getting it out of the car
It is possible you can take it out the top but it is difficult

Are you talking about the motor of the entire unit? I might leave it until next week when I have more time if thats the case! How many hours on the spanners? I guessed like 2 to get it off and back on with a new pump.

Also found a S/H D2 unit for $330, is that a decent price? According to this post Land Rover Defender TD5 ABS Modulator | LandyZone - Land Rover Forum (https://www.landyzone.co.uk/land-rover/land-rover-defender-td5-abs-modulator.227540/) you can just fit it straight to the defender even thought the ports are miss matched. OP reports back a year later with the all clear since the mod.

[djam1]

Would take me a lot longer than 2 hours maybe you are just quicker than me

[benrover]

Would take me a lot longer than 2 hours maybe you are just quicker than me

I'm not expert or speed demon, I like a good job and try not to rush anything. What would you expect the job to take? I might am probably miss estimating the job!

[djam1]

It would take me 3 or 4 to get it out and make the repair but I am a bit slow


I'm not expert or speed demon, I like a good job and try not to rush anything. What would you expect the job to take? I might am probably miss estimating the job!

[benrover]

So I finally got around to pulling out the ABS unit..

As for the diagnosis, the plungers that are meant to act as pumps have seized and will not come out so the pump was not contacting them and therefore not building up enough pressure in the line to close the callipers during a TC event.

Getting a second hand D2 unit as they can be bolted directly in place of the defender one. So within a few days the problem should be sorted and everything back together working!

Does anyone know how to bleed the breaks without a nanocom and ABS?


How To:



Undo and zip tie the lines out of the way being careful not to bend them.
Undo the plugs, and other two feeds on the ABS unit
Undo the nut below the grey plug on the from of the unit with a bit of backwards tilt and forward force you can get it out.

142945

4. Undo clip that grey from the holder bracket and then also seperate the plug.
142941

5. Turn the unit towards you so the right side is facing up.
142942

6. Then just a bit of playing with it to get it out like so
142946

Its out
142940

Here is the problem - No plungers (don't know there technical name) but they are either suck inside the unit or ground off by the seized bearing.
142943142944

Hope this helps someone

Cheers for all the help from everyone.