Good afternoon, There is only so much you can check with out the proper test equipment. The obvious is tire pressure. Which you have already checked. The next step would be to have it checked for codes using the scanner that can access the CAN bus communication system of this vehicle. The system will set a code if a problem is present. The cause may be the controller or other issue. You wont know until the codes are retrieved. It may require a special tester to test the tire pressure sensors themselves. The dealer has all this equipement and being that its a 2008, Im sure it is stilll under warranty. As mentioned, there isnt much you can check other then tire pressure with out the proper equipment.
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