how on earth do u remove the main ecu plug? ive gone through every other plug - cleaned anti corrosion and installed just cant get this one to budge-

im chasing an APPS issue, sensor tested fine, live data still shows APPS spikes and random flat tops indicating a bad wire somewhere...

 

Are you working on a Diesel or Gas. If the bolt or screw is just spinning, the threads maybe striped. When I remove connectors, I will spray them down with soapy water. No WD40.