Recently replaced the engine (4.2L) with a used engine. Original engine had 215,000 miles on it and was siezed up during a test drive when it was for sale. Used engine was complete and only had 60,000 miles. Engine now runs great but keeps throwing a P1221 code. Took to dealer and they said it needed a coolant fan clutch and computer (ECM). replaced both and reprogramed. Still setting same code and reduced engine power and SES light on. Please help!!!