Recently purchased this auto. At about 125,000 engine light came on.

What is your question?

When this happened it gave me a code of p0420 the cadilac converter. took to the dealer for the reprogramming of engine recall. Now my transmission has started slipping! Not all the time, sometimes won't switch gears or I may be driving and it s like it down shifts and jerks into gear. Please help I don't won't to be out of the money I just paid for it in May.