6BT5.9 Cummins Engine Speed Sensor 3971994 Parts Catalog Ref No. Part Name Part No. Required 1 Engine Speed Sensor 3971994 1 Above is the introduction of the 3971994 Cummins Engine Speed Sensor, while if you need Engine Speed Sensor 3971994, complete Cummins engine or other Cummins product, please further consult our sales.