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 logical successor to CHARM, I recommend you try it!

Link: lemon-manuals.la

Vacuum Sensor

NOTE: If vehicle is not equipped with a MAP sensor, it may be equipped with a vacuum sensor--some systems may not use either.

Sensor produces low voltage--approximately 1 volt--when manifold vacuum is low, and higher voltages--approximately 4.5 volts--when vacuum is high.

Normal output is 0.54-0.62 volts with ignition ON and engine stopped.