SB25-L-001A

SERVICE BULLETIN: THE ORIGINAL CALIBRATIONS IN THE ENGINE CONTROL MODULE (ECM) AND THE DIESEL EXHAUST FLUID CONTROL UNIT (DCU) OF CERTAIN 2025MY N-DIESEL VEHICLES CONTAINED INCORRECT LOGIC THAT MAY UNNECESSARILY CAUSE DIAGNOSTIC TROUBLE CODE (DTC) P2201 NOX SENSOR CIRCUIT PERFORMANCE SENSOR 1 TO SET AND ILLUMINATE THE MALFUNCTION INDICATOR LIGHT. THIS DTC MAY BE RESOLVED BY REPROGRAMMING BOTH ECM AND DCU WITH THE REVISED SERVICE CALIBRATIONS. FOLLOW THE DIAGNOSTIC FOR THIS DTC. IF NO MECHANICAL FAULT CAN BE FOUND DURING NORMAL DIAGNOSIS, FOLLOW THE SERVICE PROCEDURE IN THIS BULLETIN TO CORRECT THE CONCERN.