M

musky81

Active Member
I carried out the shuttle valve mod today as I have been having issues with 3 amigos intermittantly. The 3 amigo are still on. Has anyone ever carried out this mod but still had to do a reset with diagnostics afterwards to get back to normal? Note that I havent moved the disco from garage yet...I just turned the ignition on but seen lights remain. If I open garage door the wind will probably wreck the place :)
 
Last edited:
but did you read the fault codes before that and SVSs was the only fault logged?...and if yes did you measure the switches resistance or just made the wiring mod?..normally after rectification of SVS fault the amigos should go off by themselves
 
sierrafery said:
but did you read the fault codes before that and SVSs was the only fault logged?...and if yes did you measure the switches resistance or just made the wiring mod?..normally after rectification of SVS fault the amigos should go off by themselves
Click to expand...

I had the codes read two weeks ago when I had amigos on all the time. Codes were for shuttle valve fault and drivers rear wheel sensor. They were reset at time, wheel speed sensors all observed to operate correctly and lights stayed off for a while. Since they came up again I checked rear wheel connections and found that an unlucky fuel drip from filter conbections had dripped onto the connector so I opened and cleaned...resistance good and reconnected fine. Since still no reset I did shuttle valve mod and result as per OP. shuttle valve switches were clean and also operating correctly.
 
I thought (after an ABS fault) you needed to get up to a certain road speed after the codes were deleted/reset before the lights went out. Pretty sure mine did.
 
Disco DJ said:
I thought (after an ABS fault) you needed to get up to a certain road speed after the codes were deleted/reset before the lights went out. Pretty sure mine did.
Click to expand...

it's true... but only if the fault was SENSOR related...and only the ABS warning not the 3 amigos... and not if the faults were cleared with tester cos then the lights go out but only if the fault was rectified and not cleared with tester ;)
 
Last edited:
Hello to all

I am a newbie to this forum so please bear with me.

I own a 53 plate Disco 2 and I have had the infamous 3 amigo's warning lights that have plagued me for several months intermittently.

I have read reams and reams on this and other Forums about this topic but hope someone can point me in the right direction.

My analyser (iCarSoft) tells me that the Shuttle Valve has an electrical failure and no other fault codes such as the wheel sensors.

Shuttle valve changed for a new LR one but fault still pops up but resets on re-start.

My Disco has rear air suspension and I get the feeling that the fault could be attributed to this in some way.

The fault lights sometimes occur when the vehicle has been standing for a little while on startup and seems to be more prevalent when I have a passenger sitting in the rear offside seat. Wierd.

Any clues???
 
Hi, when you say shuttle valve changed you mean the cheap(around 30 quid) switch pack not the expensive valve assy dont you?

if it's so and you replaced only that switch pack without the wiring mod option B which appears in most of the links it's almost normal cos in 90% of cases the problem is with contacts within the modulator not with the switches themselves so if you still get that SVS fault code you must make the wiring mod then it will be OK , see this https://www.youtube.com/watch?v=l7hZQI1gfAg
 
Can't quite see your logic in associating the issues with you air suspension? That could have problems of its own, but don't see the connection.
 
this mod is completely harmless, those switches must give only brakes on and of signal that's all, here is the explanation:


The SVS issue was explained many ways but never this way, i edited the internal diagram of the ABS modulator concentrating on the SVS module(SWO500040), i marked where IMO the problems usually are with orange but in case of oil ingress to the switches those resistances(with red) will be affected and the fault is the same, with purple are the external wires of mod option B, blue is the switch pack(SWO500030), there are two important notes on the original scheme:
* TOTAL RESISTANCE INCLUDING CONTACT AND CRIMP RESISTANCE: R<0.017 OHMS for the connection which gives the main earth(that big earth connector below the multiplug
**TOTAL RESISTANCE INCLUDING CONTACT AND CRIMP RESISTANCE: R<0.04 OHMS on the refference earth(ground) circuit from SLABS to pin 8 of multiplug
SVSOPTIONB-3.jpg

so there will be SVS related fault code if the resistances of the switch pack are out of range(which from MY experience is rare) and if one or both of those two earth circuit resistances are out of that "tight" range(thats the most common IMO), so taking with external wires the switch pack in series between earth and the SLABS ECU's SVS input the internal circuit of the modulator is bypassed and the only case in which the 3 amigos will come on again is if the switches will be ruined by fluid ingress ... that's why i'm saying that the brake fluid ingress is not the most common issue cos many of those who made option B didnt replace the valve seals, some of them nor the switch pack just made the wiring mod and they haven't seen the 3 amigos generated by SVS fault code again...i hope it makes sense
 
Thanks again Sierrafery. Completely understand the issue now. Very explanetary. I will use the old shuttle valve unit I replaced which is fully serviceable to make the mod' and let the Forum know how I get on.
 
For anyone who has done this mod...as I did, you may have been continuously making checks with meter as you progressed. I was getting the expected 3kohms across my additional wires right up until the point where i connected into the slabs ecu yellow/green wire. Once connections made I measured resistanceat 1.6kohm between this soldered join and ground...thoughtwas weirdat the timebut put itdown to measuring circuit within ecu.Iwas just wondering if anyone could recall taking similar readings?
 
Btw , I cant get on diagnostic til monday so I have been checking just in case it turns out to be something simple. Also measured all sensors at ecu plug and all were around 1000ohm....the lights remain . On theverge of ordering a nanocom!
 
Just a note to give closure to question I posted but seems nobody had any info. The reading I was getting of 1.6 ohms between slabs ecu connection and earth seems fine. No fault codes and system reset. Seems I need a new rear sensor though!!
 
musky81 said:
Just a note to give closure to question I posted but seems nobody had any info. The reading I was getting of 1.6 ohms between slabs ecu connection and earth seems fine. No fault codes and system reset. Seems I need a new rear sensor though!!
Click to expand...

Or a new hub?!
 
Btw....for anyone else planning to carry out this mod, be careful how you go about it. I read a few different write ups and most were missing small bits of useful info and give advice such as splicing one of the wires into slabs ecu wire, or saying it doesnt matter which of the two wires is connected to earth. Actually these things have to be carefully considered to ensure the circuit operates as intended. As sierraferys drawing above shows it better to leave the multi- plug end of the cable disconnected otherwise you run the risk of bypassing the switches altogether.
 
You must log in or register to reply here.

Similar threads

berg450
Disco 2 3 amigos, time for SVS mod?
Replies
19
Views
2K
MJI
MJI
Muddy viking
Shuttle valve bypass fail
Replies
18
Views
3K
sierrafery
sierrafery
W
300TDi power steering pump shuttle valve.
Replies
0
Views
585
Wolf Pack
W
G
Disco 3 (LR3) Having a nightmare Discovery 3 (2007)
Replies
17
Views
1K
gawjie
G
awkwardbob
L322 EAS Inactive after puncture -Easy Reset ?
Replies
4
Views
963
awkwardbob
awkwardbob