Question

2009 Buick Enclave- check engine light on and blinking. Changed the evaporative emission control valve circuit, l&r catalitic converters, coil, sensors...truck still not running properly and check engine light still on with codes p0430 and p0420. What to do next??

Answer 1

P0420 Catalytic below threshold Bank 1

P0430 Catalytic below threshold Bank 2

If the CK ENG LIT is on and blinking you have a misfire condition. P0420 and P0430 can just be the result of the misfire .You may need to use a different scan tool that will give the a complete view of the code condition that are going on. You have a misfire code that should be stored , you can be dealing with a CAM to Crank correlation or a a fuel injector to a ignition coil. gather the rest of the codes.