Engine Control Module

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2003 Toyota Tundra, 2003 Toyota Tacoma, 2003 Toyota Sienna, 2003 Toyota Sequoia, and 2003 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

Engine Control Module (ECM) monitors and controls vehicle emissions, fuel system, ignition system and other various systems by using input signals from various input devices. ECM processes input signals from input devices and delivers output signals to various components for controlling system operation to achieve optimum engine performance for all operating conditions. ECM contains a fail-safe function which is used in case of sensor or switch failure. Fail-safe function uses preprogrammed values to provide a limp-in mode for minimal driveability. If a failure exists, ECM will inform the driver by illuminating the Malfunction Indicator Light (MIL).

NOTE: MIL may also be referred to as CHECK ENGINE light. MIL is displayed as an engine icon on instrument cluster on instrument panel.

ECM contains a self-diagnostic system which may store a Diagnostic Trouble Code (DTC) if an electronic control system failure exists. DTC may be retrieved from ECM for system diagnosis by using Toyota hand-held tester or a scan tool. See SELF-DIAGNOSTIC SYSTEMS .