October 30: LEMON manuals on a temporary server, it is slow and having issues, download the manuals you need! Later in November we will switch back to the fast server.
Circuit Operation
The engine or
powertrain control module (ECM or
PCM) receives inputs from the engine sensors and switches, controlling the functions of the engine. The ECM or PCM also turns on the "CHECK ENGINE" malfunction indicator light whenever a malfunction or abnormal engine performance is detected, and allows for diagnostic testing through the data link connector (DLC).