I do know it is a Loss Of ACM Serial Data Communication but how do i go about correcting the problem? I have been searching trying to figure it out but am not coming out with anything helpful. It is not throwing on the engine light but when scan tool is hooked up to it this code appears. If you just clear it everything goes back to working correctly other wise the air conditioning quits working. Any help would be appreciated and its on a 2004 Chevy Duramax 2500HD Thank You!!