ZF5Hp phantom signal interlock clicking

[Rewmer]

I've had a few issues with an O2 sensor which after much testing a tracing came down to a dodgy connector at the engine ecu end. Any way whilst the engine ecu was away being tested, the car was layed up for three weeks.I got the ecu back and sorted the fault but on switching on there was a click click click from the gear selector. I tried driving it down the road and the changes where all over the place, banging up and down the box and then went failsafe. cleared it a few times by switching of / on and exactly the same.

Hooked up Inpa diagnostics and eventually found the solenoid valve shift lock is flip flopping at 1 sec intervals regular as clockwork as well as the "consecutive gearshift" under gear conditions. Had a bit more of a poke around and I also have the "output speed (rpm) on analogue 1" readings cycling at the same frequency. Its worth noting that this is with the ignition on but the engine not started.

Before removing engine ecu, box was fine. the only other thing I've done is have the EWS unit out that was sent away with the ecu, this involved taking apart the lower trim under the steering column, could it be related to the brake switch? although saying that diagnostics show the brake switch working perfectly.

My other thought is there is signs of liquid on the power connector on the gearbox ecu. Wasn't wet when I took it out but sure looks like it has at some point. I had a look round for second hand ECUs but have not found an exact number match for mine, do you know if I could use a any one from the right spec/ year car and do they need any programming if I do this ?