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

Speedometer

The vehicle speed sensor (VSS) is a gear driven permanent magnet generator housed in the transaxle. The sensor generates a sine wave output with a frequency proportional to the vehicle speed. The PCM converts the signal to an output that switches to ground at a frequency of 4000 pulses per mile. The signal CKT drives the speedometer and the odometer and is used by various vehicle components.