I got my 2011 Outlander Sport installed a new amp and subwoofer. However, when I turn it on, it shows a warning regarding the Airbag. Is there something I can check before I actually send it to the dealership that Im pretty sure will charge and arm and a leg for this

 

Check your airbag lights and emergency light

 

Hmmm, airbag light and emergency light....good one. Where was the aftermarket amplifier installed? If it's under one of the front seats, then maybe a plug got disconnected under the seat.

 

most common cause, as above, accidentally unplugged something, or shorted it out when installing.
Go through your process and check everything that you ran your wires by.

If that's still not it, you may have to go to a mechanic so they can hook up an OBD

 

this message will be shown if you forgot to plug the emergency button and the seatbelt light that placed under the HU on the dashboard.

 

I also have a Sport and have had to go to the dealer (twice) to have the airbag warning light turned off. In my case and probably yours also, I had the MMCS out and started the vehicle with the VSS wire unplugged. This trips the warning instantly. I bought the Lexia tool primarily to enable the automatic door locking with speed but unfortunately it doesn't read the Sports airbag ECU. I went to 2 different dealers for the reset and just played dumb for a warranty repair. The last time the tech even wrote it up as a loose wire which I thought was pretty funny.

 

Did you try Diagbox?

 

The yellow airbag trouble light is triggered as a result of unplugging the passenger airbag status lights next to the hazard light button. It's common practice to unplug these indicator lights to remove the panel to make more room for the head unit install. The vehicle senses the indicator lights are unplugged and triggers the airbag trouble light. Simply plugging the indicator lights back in will not make the trouble light go away since it has to be cleared using a code reader capable of reading airbag codes or taking it to the dealership so they can clear it. Some high end car audio install shops may have this type of code reader because this problem is common in many other vehicles.