Brake pedal sinks to floor.
 

Hi all so the mrs 06 Nissans navara

showing abs light to rear left. Changed sensor twice and still shows same fault. Won’t clear even with vehicle static.

brake pedal sinks , have replaced master cylinder and bled correctly the whole system. Run over a litre of new fluid through. No leaks before or after. No bulging pipes or lines and still the pedal goes to floor. With engine off the pedal gets still and keep pressure on and start it goes to floor ??? Any ideas as I’m at a loss now and want to burn it !!

leeking into servo from master cylinder??

no as there is zero fluid loss and servo housing and back of master cylinder is dry. Would a faulty abs module / pump cause it. ?
have got a couple of blanks coming so will disconnect lines and test m/c but it’s new ?