Electronic Control Module (ECM): Notes

ECM is located in passenger compartment. Locations vary, but ECM is generally located under instrument panel behind glove compartment or behind passenger footwell kick panel.

ECM is the central location in which information from various sensors and controls are gathered. ECM also performs the diagnostic function of the systems that affect vehicle performance. Information from all data sensors is received and processed by ECM to produce proper pulse duration ("on" time) for injector, correct idle speed and proper spark timing. ECM performs calculations to control following modes of operation such as starting, clear flood, run, acceleration, deceleration, battery voltage correction and fuel cut-off.

ECM's have "learning process" capacity. If battery is disconnected, process must begin all over again. During this period, change may be noted in vehicle performance. To "teach" vehicle, ensure vehicle is at normal operating temperature. Vehicle should then be driven at part throttle with moderate acceleration and idle until performance returns.