Key wont disarm the imobiliser.

[Just_Ben]

It's not the earth, that's only the earth for engine starting electrics.
The fault is, as stated, unrelated to the remote battery failing. The imobiliser runs seperately. You DEFINATELY have an imobiliser fault. If one key works then it's not the imobiliser or it's wiring as this would affect both keys. Did the key in question work before? If the car has "forgotten" the key (it shouldn't do but not impossible) then it needs to be re coded with security coding. I can do this but I'm based in Daventry now rather than Burton (AVP) but yeah, Ben Wardle at Shark should be able to do also.

As for the remote (purely for central locking) to re allign you insert the key into ignition and turn igniton on (engine NOT running) then hold Unlock button on key for 10sec. This should bring it back in line but ONLY if the key has previously been coded to that car - this process won't work with a brand new remote and would need VCDS