F 350 4WD Super Duty V10-6.8L VIN Z Bi-Fuel (2001)
Speedometer Head: Description and Operation
Speedometer
The electronic speedometer receives a speed signal from 4-Wheel Anti-Lock Brake System (4WABS) module (if equipped with 4WABS) or the Generic
Electronic Module (GEM)/Central Timer Module (CTM), if equipped with Rear Anti-Lock Brake System (RABS).