Thread: what does the shuttle valve switch do....?

Zook,

Check in the Disco 2 forums. The Defender and Disco 2 share the same basic ABS system - WABCO D Type, so there is a lot of commonality between the two.

The shuttle valve switches are part of the modulator and detect the state of the shuttle valves. The ABS ECU constantly monitors these switches and will tigger a fault if they are non functional.

There are three possible failure modes.

- A soldered connection in the modulator block can crack causing an intermittent fault, which eventually fails. This can be fixed by replacing the modulator block (SWO500040 on the d2) or performing the what are known as option-a or option-b mods. see ABS Mod - LAND ROVER CLUB V.I.

- The shuttle valve seals deteriorate and leak contaminating the shuttle valve switches causing failure. ABS SVS Seals - LAND ROVER CLUB V.I.
and http://www.jewellamberoil.com/sales/...roducts_id=247

- The shuttle valve itself fails. (SWO500030 on the D2)

From this post on LRO forum it appears the D2 parts fit the Defender ABS modulator as you'd expect:

Land Rover Owner • View topic - ABS modulator shuttle valve switch (TD5)

I'm a bit surprised these faults don't occur more often on the Defender as the ABS Modulator is of the same make and type as the D2. Perhaps it's simply a case of the D2 working the modulator harder resulting in failures occurring sooner?

hope this of some help.

cheers
Paul

Thanks Paul......that's a great help......

I've got a rave cd somewhere.....but my mac doesn't wanna read it....so I'm a bit stuck.....

I'll check out those links and hopefully get it sorted......


Cheers.....

Just had a look at those links.......it clears everything up now.....

It's either leaking seals......or a bad connection......either way is a very simple repair.......will take a bit of time.....but it's pretty straight forward......


Thanks again......I now know what I need to do and where to start........

Another fault is a shuttle switch sticking/jamming.

I take it you've taken out the sensors, cleaned them and pushed them back home? This is much more often the way to solve abs issues.

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Originally Posted by Yorkshire_Jon

I take it you've taken out the sensors, cleaned them and pushed them back home? This is much more often the way to solve abs issues.

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ive only done it with the right hand front one.....as that was the only one to throw a fault up......
also....that was the side the swivel hub bearings had collapsed on......

but I'm also getting the shuttle valve switch fault......
ill have a look at it when i get time to pull it apart......cant do that right now as ill have no way of getting to work if something goes wrong......
or if i need to get any parts........

Originally Posted by DEFENDERZOOK

ive only done it with the right hand front one.....as that was the only one to throw a fault up......
also....that was the side the swivel hub bearings had collapsed on......

but I'm also getting the shuttle valve switch fault......
ill have a look at it when i get time to pull it apart......cant do that right now as ill have no way of getting to work if something goes wrong......
or if i need to get any parts........

I'm bait saying the shuttle valve isn't at fault, only that there are much more likely things to be causing that error that have a much simpler fix.

All you need to extract the sensors is a pair of pliers and 10 mins. Grab the sensor by the
Sensor shaft, not the wire on the end. Grab, rotate back and forth and pull out at the same time.

Once out, look into the hole from where the sensor came and check that the relict or ring has no crud in any of the depressions. Also wipe clean the sensor. Push it back in, all the way home.

I no crud found check all the wiring for issues.

Also, even if you rectify the fault you will need to reset the ecu before the lights go out.

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