Operation CHARM: Car repair manuals for everyone.

Vehicle Speed Sensor: Description and Operation

A Vehicle Speed Signal is sent to the Motronic control module from the Vehicle Speed Sensor located in the transmission, the signal is directional IN only (PIN 65 - INPUT ONLY).

The vehicle speed signal is information about the current vehicle speed and is supplied to the Motronic control module via the speedometer.

The signal is used for idle air control (active below 4 mph) and A/C compressor cut-out.

Self-diagnosis:

^ Self-diagnosis (OBD) recognizes the fault "no signal".