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

OPERATION
The vehicle speed sensor signal is provided to the PCM by the TCM. The signal is calculated by the TCM based on the output speed sensor signal and the speedometer pinion factor. The PCM supplies a 5 volt pull up voltage from cavity 66 to TCM cavity 58. The sensor signal is created by the TCM alternating the signal from 5V to 0.3V.