ECMs generally can't be repaired without specialised tools and skills; even then, it is much cheaper and more practical to replace with a new one. ECMs usually aren't designed to be repairable. Further, make sure you don't have any other faulty sensors/computers in your car that could have damaged the old ECM with faulty readings and that could damage the new one too. Before you replace the ECM, take the car for a sensor and electricals check up to the Bosch or ACDelco service centers. Best of luck.