AEG 65050 VI error 30 – leak prevention but there is no leak

I have an AEG 65050 that is giving error 30, flood protection, with the pump running constantly.

I have done a lot of work trying to fix the problem and thought I would post here for any advice before I replace the machine.

There is no water in the sump so there is no leak and the error is incorrect.

The float is moving freely and the microswitch is working, I’ve tested with a multimeter. I’ve even bypassed the flood protection microswitch with both an open circuit and closed circuit to check this is not the problem.

I have checked as much of the wiring as I can access easily for loose connections and there is no sign of damage to any wiring.

The controller board did have signs of damage with a blown chip (whole in chip packaging) and burn mark on the case so I replace the board with a new one but I just get the same error 30.

I have tried the test cycle – holding button 1 and 3 when power on – then selecting button 3. The display shows 21 then counts down to 20 but then reverts to error 30 again with the pump running.

Is there any other common reason these machines show error 30? Is there a way to test that the wiring is working at the circuit board – which wires at the circuit board are related to the leak detection system and how can I test them?

Can anyone offer any advice on what I should do next?

Its getting old so may just be time for a new machine.

Thanks,
David