"Diesel Intake Carbon Cleaning. The Service Engine Soon light is on and the engine may run roughly. Possible Fault Codes stored: * 3FF1 air mass sensor * 4595 rough controller Cylinder 6 * 459B rough controller Cylinder 5 * 4592 rough controller Cylinder 4 * 4596 rough controller Cylinder 3 * 4593 rough controller Cylinder 2 * 459C rough controller Cylinder 1 CAUSE Based on the above stored ""Fault Code"" profile, there is excessive carbon buildup in the intake system."