When you push start button dryer will start but will not stay running, If you hold the start button dryer will continue to run and heat. troubleshooting guide said check P2 connector, push to start switch, thermal test, and door switch these all checked good so it said to replace the electronic control unit, I did this but it does the same thing, Any Answers??
Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=gew9878jq1
Sounds like you have the tech sheet but just in case you do not here it is
http://www.servicematters.com/docs/wiring/Tech%20Sheet%20-%208532036.pdf
You will see that the Motor Relay is wired in parallel with the Push To Start switch so odds are good that this relay is toast. Either the relay is not pulling in or it’s contacts are shot.
I believe that the Motor Relay and the Heater Relay are the same so swap them. If now it runs but you have no heat you know that the relay is shot.
Note: I am not 100% sure on this so check that the relays are the same.
Also it would be a good idea to check the Motor Relay coil with a meter to make sure that it has not shorted out internally which could blow the new board.