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

Engine Control Module: Description and Operation






The powertrain control module needs the following inputs to calibrate the engine properly:
^ crankshaft position
^ engine rpm
^ engine load (manifold pressure)
^ atmospheric (barometric) pressure
^ engine coolant temperature
^ amount of engine detonation