Common Rail diesel injection systems become more and more advanced nowadays. In order to detect a malfunction in this system, measurements have to be much more accurate. Introduction of pressurized return flow systems makes measuring the return flow using open "jars" impossible.

The Diesel Return Flow Sensor RFS400 is a closed system four channel flow sensor that can be placed in the return flow circuit of a Common Rail diesel engine. Connected to the Automotive Test Scope ATS5004D with ATIS software, the small return flows of four cylinders can be measured simultaneously and accurately. A graph for each cylinder shows the size of the fuel flow. Due to the closed system, no diesel is spilled, keeping the work area clean. It also makes it possible to perform measurements while driving the vehicle.