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

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Light Duty

PURPOSE
Engine speed is used to derive shift times, control line pressure during a garage shift, generate TCC slip, and check the MIL.

OPERATION
Engine RPM is determined by two different methods. On gasoline vehicles this value is determined from the distributor. On diesel vehicles there is a separate speed sensor located on the rear of the intake manifold.