Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Vehicle Speed Sensor: Description and Operation

The Vehicle Speed Sensor (VSS) sends a pulsing voltage to the Engine Control Module (ECM), which the ECM converts to miles per hour. This sensor mainly controls the operation of the Torque Converter Clutch (TCC) system.
The function of the of the VSS signal buffer, used in past model years, has been incorporated into the ECM.