Whirlpool G2P DWI/1 WH Heater fault?

Seeking advice on a repair for my Whirlpool dishwasher model number 8542 347 15819 please!
It started with a constant beeping after running a wash cycle and 3 flashes on the control panel. There was no steam and dishes were still wet too.
Running the diagnostic program gave no errors and heated up ok.
I ordered a replacement heater but this still gave the same fault. The original heater also tests out ok – not open circuit.
I then went on to remove the control PCB (and one capacitor was bulging. 470uF 25V CapXon. I’ve replaced this with the equivalent Panasonic.
Now running the diagnostic gives the 3 flashes error! Other programs also running cold and giving the 3 flashes heater error and beeps again.
Does this sound like further problems on the circuit board? Any advice welcome! Thanks!