The U.S. EPA together with engine manufacturers have come to an agreement on a software bypass patch that will prevent heavy duty diesel engines from shutting down automatically due to faulty DEF fluid sensors. The software bypass is needed due to the current COVID induced worldwide shortage of microchips needed to manufacture DEF sensor replacements. The sensors are designed to illuminate indicator lamps inside the cab at three intervals to signal when DEF level is; “low”; “empty” and “empty and ignored”. The third warning light reduces power in the engine to a maximum 5 mph until DEF levels are restored or the faulty sensor replaced. The issue is important to energy marketers because DEF sensors, which are currently unavailable in the marketplace must be replaced on a regular maintenance schedule. Without the software bypass patch, cargo tank vehicle engines with a faulty sensor will not operate and must be taken out of service.
EMA worked closely with EPA on this issue since the problem was first reported. The software bypass is a temporary fix until new sensors are made available. The bypass is only available to vehicle owners after the DEF sensor fault light indicator signals the first of three warnings before the engine is shutdown. Software patches will not be made available if no sensor lamp is illuminated. The computer bypass will be made available at heavy duty truck dealers and service centers. Since there are many different types of heavy-duty diesel engines, manufacturers must create a software bypass for each one. According to the EPA, engine manufacturers have already released many software bypasses to dealers and service centers and is expected to release the rest before the end of October. Energy marketers should contact their dealer/service center to see if the correct software patch for their vehicles is available. Once the microchip shortage is resolved and DEF sensors are readily available again, the EPA will establish guidelines for removal of DEF bypass patches. Contact Mark Morgan, EMA Regulatory Counsel with questions or concerns at markmorgan@verizon.net.