T

TattyD

Member
Familiar topic I'm sure...

Busy clearing the MOT fail list on a Disco 2, pretty much the only thing left is the Three Amigos but I've had no luck sorting it. (Been through the threads here and elsewhere but not seen anything obviously similar to the problems below).

Spec:
Disco 2 2004
Td5 Auto

History/Diagnostics:
  • Intermittent 3 Amigos turned up end of last summer, just in time for MOT :-( . Began as an intermittent fault but quickly became permanent (all three lights). Never seemed to stop the ABS functioning.
  • Failed the MOT and the garage were useless about sorting it (and other bits) out so ended up doing it myself.
  • I've pulled off and cleared the fault codes, nothing was current only a few historical. Cleared them off, currently has no fault codes on the ABS but the dash light is still on, all others have gone out.
  • Limited space for test driving it on the drive but moving it about doesn't bring up anything new.
  • Voltage read-outs for the inlet valves came out at 1.4v for all but one (LF) which fluctuated from 0.7 to 0 V. This was static, when in motion they dropped to around 0.7v.
Given the ABS warning light remained on after binning the fault codes and without moving the vehicle I figured the fault was probably a system thing rather than a sensor, bearing or brake issue. And the variation in the inlet valve voltages had me thinking that was a possible.

Wabco give the voltage as quite far off what I was looking at:
Inlet valve: This shows the voltage being applied to this valve by the SLABS ECU. When driven, the voltage should be around 2.8 to 3.6 Volts and when not being driven, should be around 0 to 0.5 Volts.​

I've pulled the modulator switch, resistance looks fine (3k-ohm for both open(?), 2k for one shut, 1k for both shut) - so figuring it's not that. No sign of anything other than a film of brake fluid, nothing to suggest a serious valve leak.

I've got the historical fault codes so will stick them on here once I'm back from work.

Anyone with thoughts, would be appreciated. I am looking at an ABS module fault or am I barking up the wrong tree altogether?
 
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The only sure-fire way of understanding the cause of the 3 amigos is to connect a diagnostic device designed to interface with the Disco 2 system such as Nanocom, Hawkeye, Lynx or Testbook. The Disco 2 is not OBDII compliant.

The usual causes are either a faulty hub (ABS wheel speed sensor or reluctor ring) or the shuttle valve switch connector inside the ABS modulator. Some people might suggest that the problem lies with the battery, but I have yet to understand that particular fault mechanism.

Trying to identify the trouble with a multimeter I would suggest isn't barking up the wrong tree, but it is probably going to lead you up the wrong garden path.

If you are unable to get hold of a diagnostic device, then I would suggest that you try installing the shuttle valve switch modification first. If the problem is not there then it won't cost anything and you'll know that the problem lies elsewhere. Once you have done it, there's no need to remove it, it only bypasses a dodgy connector. You say that you've checked the resistance values of the switch plate, but the problem in that area is not usually with the resistors or the switches but with the two pin connector and the mod will deal with that.
 
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What diagnostic did you use?

I had problems with mine, only sorted by code clearing with a Hawkeye, no luck with any generic kit
 
as far as i can remember once abs fault is cleared, the car needs to be driven above I think 9mph to clear fault so abs sensors can get a reading
 
Hi, cheer Brian/MJI,
Yeah, I've had it on a Lynx.

Only had fault codes listed as historical, cleared them out and the HD & TC lights went out, but ABS is still on. Except now it doesn't show any codes.

Aye, I think I've seen that switch mod. Might give that a go, though I read the resistance off at the connectors so if it or the wires were properly knackered you'd be getting infinite (or lots of) resistance? That said I've not yet checked the main unit so if the connector is bad on that side it wouldn't show so far.

Sensor voltage is all the same (apx 2 V) with live-data so I'd have thought they're okay. Given that everything but the ABS cleared I'd be surprised if the issue was with the wheels as it was still there without moving, so it wouldn't have read any data through to give a fault? But if you're right MJI it might be an issue with the Lynx.

I've got the brake discs to change tomorrow anyway as they're looking a bit tired so I'll have a look at everything in that area at the same time.
 
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davidsmith1307 said:
If you can't get any speed up then how do you know you have an ABS fault? The light only ever goes out once you are moving at a few mph.
I think...
Click to expand...
Really, never noticed? Might do.

However I had all three lights with normal driving before I cleared the code so I'm something was there unless they've gone on and not turned themselves off.

I'd guessed at the time it was a wheel-bearing or sensor which I figured the garage could do when they did the MOT but instead they just did a crappy job and tried to persuade me to scrap it. Suppose it's a change from them trying to charge you a fortune for nothing.
 
If you get the codes read "properly" then there's none of all this guess work! That's the idea, they tell you where fault is.
Codes will all clear the lights except ABS, as said you need to drive it to clear it.
If I were a gambling man I'd bet you DO have a sensor issue and you WILL be changing a hub in the near future!!!
 
Disco DJ said:
If you get the codes read "properly" then there's none of all this guess work!!!
Click to expand...

Aye, well I have the fault codes from the Lynx. But do you just mean the Lynx isn't up to much? Probably a separate topic.

Edit: Fault codes attached...
Initial ABS faults:
d2-intial-abs.JPG

Running data:
d2-sensor&valves.JPG


Of those faults none have returned but maybe it's just a because it's not had a test drive.

There were a load of other non-ABS things flagged but I'd head the engine head off after it popped which probably accounted for them.

Might just have to try it with another MOT then and see what happens.
 
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I have to pay for the codes to be read, as I don't have a tester.
The info I get is relayed to me as (eg);
"Intermittent fault, abs sensor ring, rear left"

I then change (eg) the rear left hub and fault is cured (after fault lights reset again)

This has happened a couple of times (changed 5 hubs now!)
 
Itsalready been said a couple of times and its correct !! You need to get off the drive and get the speed up. I had faults and 3 amigoes cleared on tuesday. The abs light didnt go off until we were up over 10mph. If there are no fault codes on diagnostic then you can be fairly sure the faults have been cleared. Not sure how much of an issue it is escaping your drive but i wouldnt waste any more time with other checks until youve done this. Certainly wouldnt go for an mot until you clear as it will fail.
 
The only one fault which would leave the ABS warning on alone untill the vehicle exceeds 9.4mph is sensor related, for all the other faults clearing them would clear the warning too without driving it, according to the list of codes and live readings your problem is most likely the front RH hub cos as the sensor is passing the stationary self test the fault is recorded while driving which means play in the reluctor ring... the inlet/outlet valve readings are good between 0 - 0.5V stationary so your's are OK, forget about the modulator cos your fault as i said is sensor related(only 4084 is relevant in this case), my money is on the hub... the other faults(4130/36/37/66) are SLS related they have nothing to do with the ABS just that being stored in the SLABS the tester displayed them all

be aware that cheap hubs can have less slots on the reluctor ring(55 instead of 60) and they'll mess up the whole ABS system and make the TC to kick in unwanted, if you can't afford a genuine hub better go only for the bearing side of it cos it became available again, it can be sourced from reliable/good brand manufacturers under TAD100020 part number(some shops are sending directly to the complete hub TAY100060 but IMO this bearing side of it is important, only an extractor is needed to replace it on the flange, a good alternative for UK is this http://www.onlinecarparts.co.uk/skf-7182678.html but you can google out any of the parts listed here http://boodmo.com/catalog/part-wheel_bearing_kit-5365265/ , a friend of mine just bought a pair of Quinton Hazell from a local supplier at a good price and IMO it's far better than mix up the whole ABS system with a cheap hub

btw lynx is a brilliant tool for D2, 100% reliable as it's built by Omitec on original Testbook T4's protocol
 
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Cheers guys.

sierrafery said:
btw lynx is a brilliant tool for D2, 100% reliable as it's built by Omitec on original Testbook T4's protocol
Click to expand...
Ha ha - that's good to know then.

musky81 said:
Certainly wouldnt go for an mot until you clear as it will fail.
Click to expand...
Aye, true that but in the middle of town so no convenient field or lane for a test run.

Sounds like it's worth doing the hub, then fingers crossed.
 
TattyD said:
Aye, true that but in the middle of town so no convenient field or lane for a test run.
Click to expand...
You have to exceed only 9.4mph to make the light go out, maybe putting it on axle stands and make it run in gear would help if you dont want to drive it a bit
 
Update:
Got a test drive done last week, like (bad) magic everything lit up again & definite fault code from the RH front hub.

Only had chance to get back on it today. Hub is a heap of rust but got all but the axle nut off. That begger I cannot shift, knocked the stake out then tried my breaker bar, breaker bar + cheater bar, penetrating oil, blow torch, my fat ass stood on the bar... until ran out of ideas.

Any trick to it? Or is it just welly until it goes?

Everyone else I've read over on make it annoyingly easy.
 
TattyD said:
Update:
Got a test drive done last week, like (bad) magic everything lit up again & definite fault code from the RH front hub.

Only had chance to get back on it today. Hub is a heap of rust but got all but the axle nut off. That begger I cannot shift, knocked the stake out then tried my breaker bar, breaker bar + cheater bar, penetrating oil, blow torch, my fat ass stood on the bar... until ran out of ideas.

Any trick to it? Or is it just welly until it goes?

Everyone else I've read over on make it annoyingly easy.
Click to expand...

It isn't a left-hand thread is it?
 
GingerPuss said:
It isn't a left-hand thread is it?
Click to expand...
School boy error? At the risk of looking stupid I had checked the new one and it felt like a normal thread.

chris07 said:
Use a hammer and chisel
Click to expand...
Yeah, might be a job for that. I'd be tempted to use a nut splitter but I'd not get one in.

Annoyingly had to reassemble everything today to move it across the drive and get a delivery in. Might have to take it to the local garage and see if they can get it started (then drive cautiously home - ha ha).
 
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