Traditional gasoline car fault

No Communication Issue with 2007 Ford Fusion 1.4 - No Power, No Cranking

My 2007 Ford Fusion 1.4 is not communicating with the vehicle system. Only the oil light is on. There is no electrical power at all—no interior lights, no dashboard illumination...

2007 Fusion 1.4 | P2186

1999 S70 Volvo, Service Comunication link failure

I don't know what the code number is but this is what the explanation of it was. Any ideas what to do to fix? Or what is causing the fault. Thanks, Mark

1999 S70 Volvo | P2186