July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!
Speed Sensor
The speed sensor mounts on the flywheel housing and monitors the rotation of 2 slots in the flywheel. It provides a signal to the ECB which permits EGR to only occur above 1300 RPM.
Fig 1: Peugeot Diesel EGR System Vacuum and Wiring Diagram