Immobiliser fault Yaris

[Tony456]

Hi,

My Yaris  (2011, 1.3l, petrol) was sometimes starting perfectly, sometimes not at all. Relevant ignition lights would come on, but turning the key the final bit led to absolutely zero firing of the engine. Same thing happened with both keys I have, including after changing the key batteries to new ones. The refusal to start was annoyingly sporadic...sometimes after 9 or 10 tryst it would suddenly work, at other times it would start perfectly first time.

Is it likely an immobiliser problem?

Is it more likely a loose connection somewhere than the actual immobiliser unit?

It's currently in the main dealers awaiting a diagnostic test (in 10 days time!). It's there 'cos in the end it just wouldn't start and I was ready to call a tow truck, but miraculously it then fired up so I drove straight  to my local dealership.

I see the whole dash has to come out, to replace the immobiliser unit (behind glovebox in my model), which must be a lot of labour time. Any idea of the cost?

And and is this really only a job the dealership can do (a couple of diagnostic garages said that was my only option)?

Thanks