18-027-16 REV. A

Flash: 6.7L Diagnostic And System Improvements This bulletin involves reprogramming the Engine Control Module/Powertrain Control Module (ECM/PCM) with the latest available software. DTCs have been changed from a one trip fault to a two trip fault: · **P0421 - Catalyst 1 Efficiency Below Threshold Bank 1.** · P2280 - Air Flow Restriction / Leak Between Air Cleaner And MAF. · P203C - (Diesel Exhaust Fluid) Reductant Level Sensor Circuit Low. · P208D - (Diesel Exhaust Fluid) Reductant Pump Control Circuit High. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation a technician may find the following Diagnostic Trouble Codes (DTCs) set in the PCM memory: · P2281 - Air Leak Between MAF and Throttle Body. · P218F - Reductant No Flow Detected. · P0218 - Transmission High Temperature Operation Activated (68RFE Only). · P0868 - Line Pressure Low, MIL Action (68RFE Only). · U110E - Lost Ambient Temperature Message. · P205E - (Diesel Exhaust Fluid) Reductant Tank Temperature Sensor Circuit Intermittent (setting when the block heater is plugged in). In addition to addressing the above DTCs, the following powertrain system improvements/enhancements are also included in this software release: · **Reduction in engine noise during regeneration at idle.** · 68RFE Transmission Overall Shift Quality Improvements. · Test results fix for partial range misfire (68RFE Only). · Ambient Air Temperature Improvements. · Stationary Desoot with wiTECH Fix. · OBD Misfire Monitoring Improvement (68RFE Only).