WRX Link 7-9. Doesnt power on with key on

[MitchSavage]

Just got a link G4X yesterday, powered on and could connect to it

Tried to use it today and it wont connect

With key off and acc light on ecu comes on, key on and light turns off

Only thing that changed is I had it on trickle charge overnight (Yes had positive and negative the right way)

Engine isn't currently in the car but was working fine yesterday

Have tried reinstalling pclink and yes its the right version, have also tried unplugging ecu and battery to reset it but no luck

[Adamw]

Did you try the jumpers in both positions as per the manual?

 

If that doesnt help I would guess without the engine in it is possibly missing one of the main grounds or similar that are required to power up or engage the main relay.  

[MitchSavage]

Yes I started with it in the STI yesterday, it didn't work so took the case off and realised the lights weren't on then remembered reading this. So then changed those over to the WRX pins and it worked. Then today I got the unlock code as it was to late yesterday to ask the dealer for it. When trying to connect to my laptop again today it had the issues i mentioned prior.

I managed to get it to work after a while by leaving it unplugged for longer but i couldn't figure out why the issue actually occurred in the first place

[Adamw]

If the LED was going out it is a power supply issue.  As I mentioned above most likely a main ground path missing somewhere since the engine is out.  The ECU is probably just getting barely enough current to power up intermittently via a current path through a sensor or relay coil or similar.