My options after buying a troubled high mileage Rav 4

[ShaneinTX]

I bought a 2008 Toyota Rav 4 with about 175,000 miles in Texas from a dealership that sells new and used cars. I bought this vehicle on an "as is basis" with no warranty. The car was inspected by an independent garage before the purchase. Everything was found to be in working condition. The dealership said the car has been checked and would pass state inspection.

I drove the Rav4 about 60 miles from the dealer immediately after purchase. The check engine light, the VSC light, and the slip indicator light came on. The diagnostic system shows the following codes:

P0420 - Catalyst system efficiency low.

C1201 - Engine control system (ECM) Malfunction - ECM is not able to work with the Electronic Stability Control System and Anti-lock Braking System.

I have tried to contact the dealer. There is no response yet during this holiday weekend.

What are my options at this point given that I bought this vehicle on an as is basis? Is the dealer responsible in any way for selling a defective vehicle that cannot pass state inspection? Do I have the option of cancelling the payment made to the dealership?