I would like to know where is the purge valve on a Srx Cadillac 2012

I’m not sure but I think the newer cars don’t have one.

The EVAP purge valve is connected to the EVAP canister and is located at the rear of the vehicle.

Should be on the top of the motor on the drivers side. Remove the plastic engine cover to get to it.

ACDelco® - GM Original Equipment™ Vapor Canister Purge Valve more details on - https://www.carid.com/acdelco/gm-original-equipment-vapor-canister-purge-valve-mpn-214-1685.html

What engine ? 3.6 or 4.6L

Evaporative Emissions (EVAP) Canister Purge Solenoid Valve (LH2)
In the back of the throttle body, center front of the engine
Engine Controls Component Views for the 4.6L (LH2) engine
Engine Controls Connector End Views for the 4.6L (LH2) engine
Evaporative Emissions (EVAP) Canister Purge Solenoid Valve (LY7)
On the right side of the engine near the valve cover

http://www.certifiedmastertech.com/wordpress/2012/08/01/cadillac-timing-chain-problems/

Hope this helps

Did you check on you tube ?

Raise and support vehicle.• Remove right rear wheel housing liner, see Repair Manual Body Exterior Group 66 - Exterior equipment, "Rear wheel housing liner, removing and installing" in ElsaWeb.• Disconnect T-3 electrical connector at Leak Detection Pump (LDP).• Disconnect EVAP purge line, EVAP vacuum Line and EVAP vent line from EVAP canister.

tech 2 at dealer

Probably a Bluetooth compatibility problem. Just because they paired doesn't mean the drivers in both devices are currently compatible (one of them may have been updated without you knowing). You will have to dig deeper and determine what the current Bluetooth versions are on each and then check compatibility.

po 443 bad evap purge vavle.