EXTENSION 9S4028 - Caterpillar

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
There have been some instances of faults with the 390-5194 Exhaust Gas Valve Gp (NRS). The faults result in the aftertreatment system being unable to regenerate and may be indicated by one of the following event codes:
E1263 Engine Exhaust Back Pressure Regulator Not Responding to Command
E1265 DPF Active Regeneration Inhibited Due to Low Exhaust Gas Pressure
E1645 Aftertreatment Active Regeneration Inhibited Due to Low Exhaust PressureThe fault may result in the valve being off-center when not powered. The fault may result in the valve not moving when commanded.Solution
Follow the Troubleshooting procedures for the active event codes.If a fault is found with the exhaust back pressure valve, install a replacement 390-5194 Exhaust Gas Valve Gp (NRS). Refer to Disassembly and Assembly, Exhaust Back Pressure Valve - Remove and Install.Install the latest engine software. Refer to Troubleshooting, ECM Software - Install.Use the electronic service tool to take a Product Status Report (PSR) and take photographs of the removed valve. Provide the PSR and the photographs along with TIB Media number M0078804, CPI number 368689, machine serial number, and service hours through "CPI Feedback" within the Service Information Management System (SIMSi).