In the “Idle Clatter” column in the Turbo Diesel Register, Issue 89, we briefly discussed the dashboard check engine light (CEL) and what it means. As a TDR member you can download the diagnostic trouble codes (DTCs) that turned on the check engine light using a code reader/scan tool and interpret what they mean. You then can know where to look to fix the problem. A good mid-priced scan tool is therefore the next recommended item to go into your tool kit. The scan tool is plugged into the OBD2…