I recently bought a new Tahoe High Country diesel about three weeks ago and it is in the shop for the 3rd time for the check engine light. After driving for a week, I had the same issue, the check engine light came on. The dealership had it for about three days and said they had to update the software. The very next day after I picked it up, the check engine light came back on again. I took it back to the dealership which they kept it for four days and said they said they had to replace an oxygen sensor. After four days, the check engine light came back on again. The dealership has had the vehicle for one week now and they said they are consulting with engineers at GM because they do not know why the engine light is coming on. Although the dealership gave me a loner vehicle, it is very frustrating since I paid 80K and it has been in the shop longer than I have driven it. I live in Texas and the Lemon Law for Texas says if you take a new vehicle back for repair under warranty for the same issue for four times in a 24 month period, then the vehicle is considered a lemon. There are some actions you have to take here in Texas to have GM buy back the vehicle. For instance, you are required to mail GM (not the dealership) a certified letter to the address listed in the warranty book requesting that they correct the problem within 30 days. If the issue continues after you mail the letter, then you can file a complaint with the supporting documents (repair invoices, letter to GM) to the Texas Dept of Motor Vehicles and either the case is mediated or a hearing is set. There are also attorneys that will take your case for no fee as they will collect their fees through GM. If the problem recurs when I get my Tahoe back, then I will be starting the process of sending a letter to GM and filing a lemon law complaint.