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

Control Unit Basic Operation

Motronic Engine Management:





The Motronic Engine Control Module (ECM) processes input signals, filters out stray signals and sends the results to the operating components of the fuel injection and ignition systems.

The ECM also provides for self-diagnosis of the Motronic system. The Motronic system is adaptive or self-learning. The ECM learns continuously by using a sophisticated feedback system to constantly readjust the various basic control settings. These values are then stored in its electronic memory.

The adaptive capability allows the ECM to compensate for changes in the engine's operating conditions, such as altitude changes, intake leaks or other deviations.

If the vehicle battery or Motronic ECM is disconnected, the vehicle must be driven for a few minutes so the Motronic module can "re-learn" its operating conditions.