You mean that ı should replace abs pump with a new one?
I don't know, it doesn't sound like the same errors I had.
I just googled "internal valve relay error" - there's all sorts of rather general results returned, nothing to clearly highlight what is wrong - from a quick scan of the results.
In this one...
OE ABS valve relay error (going to need a beer now) Technical Help Forum
the75andztclub.co.uk
A chap reported "OE ABS VALVE RELAY ERROR" and that was cleared by replacing the modulator - but I don't think that would have been a WABCO.
This link...
appears to show documentation from/about WABCO. It explicitly references a "Internal valve relay". Its diagnosis for this states that if it can't "switch off" "Replace ECU - Internal failure" and if it can't "switch on" then check a fuse and if that's OK then replace. So these do not appear to relate to the modulator - rather the ECU and its wiring.
This link...
describes the "Internal valve relay" as "provides supply voltage for ABS pressure control valves" - I dunno if this would be in the ECU or modulator. It ties in with the same info as the link above with errors, so you'd assume its the ECU.
But then I come across this link...
Discovery II - Three Amigos Time to deal... - I've been ignoring the Amigos for too long now. Time to deal with them. I had to get $1000 of brake work done just to get the brakes up to scratch - rotors, pads, stuck callipers... that kind of thing. Turns out I just don't drive her enough for...
landroverforums.com
Its a Landie link for WABCO on D2. It references your error and shuttle valves. Unfortunately the "option B" they refer to is in a link that no longer exists - but I presume is the oft use home fix for the shuttle valve errors.
Up to you what you make of all this. If you can get a cheap modulator and don't mind brake fluid ****ing out everywhere no matter how tidy you try to be, and fully bleeding the brakes - you could give replacing the modulator a go. I got both mine pretty cheap, but that was a few years ago, I bet they are getting quite difficult to come by now.