Toyota 1994 Engine Performance Theory & Operation PDF Manual Guide

This article deals with basic description and operation of the engine performance related systems and components. Read this article for diagnosing vehicles or systems that you are not completely familiar. The TCCS is a computerized emission, ignition and fuel injection control system. The TCCS reduces exhaust emissions while maintaining good fuel economy and driveability.

System consists of sensors, switches and control units. See Figs. 1 and 2. An Engine Control Module (ECM) regulates the TCCS based on input signals received from different input devices. The ECM contains data programmed to maximize engine performance under all conditions.

Engine Control Module
The Engine Control Module (ECM) micro computer receives input signals from various sensors, switches and the ignition and starting system. The ECM uses this information for controlling various functions. See output signals under Computerized ENGINE

The ECM has constant battery voltage at BATT terminal. The ECM is a fail-safe function, which is used in case of a sensor or switch failure. Fail-safe feature uses preset values for a limp-in mode for a minimum driving. If a failure, ECM, the driver turning Malfunction Indicator Light (MIL) on the instrument panel. Note: The MIL lamp may also be referred to as the check engine light.

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