Pontiac Grand Prix SE 3800

My '95 Bonneville did that for a while. I found a buildup of crud in the bottom of the overflow tank and the tube leading to the radiator. It seemed to be restricting flow past the sender enough to make it send a false "low coolant" signal to the computer. I cleaned that out and the problem never reoccurred. Just a thought. If the rad is full and the engine's not overheating I'd say there's nothing to worry about i that regard. Google the codes to see what they mean and what the possible problems might be. Do your homework before starting to replace parts.