18-015-17 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. The following Diagnostic Trouble Codes (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 DTCs set in the PCM memory: P1451 - Diesel Particulate Filter System Performance. P229E - NOx Sensor Circuit - Bank 1 Sensor 2. P0128 - Thermostat Rationality Improvements. 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: Improvement to correct engine feels like low or reduced power. Engine Noise Improvements. Engine Hesitation Improvement. Improved Engine Fuel Economy. 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).