TIAGO BSVI MCE - SERVICE MANUAL

1.2L REVOTRON ENGINE 138 B. An Overview :  Engine Management System Overview : Modern engine management systems do a fine job of ensuring that engines run cleanly and efficiently in a wide variety of conditions, they are for the most part reliable and require little or no maintenance. Engine management system Comprises of Electronic Control Unit (ECU), Sensors, Actuators, Wiring Harness and control algorithms, which determine the performance of the Engine as a whole and as part of the vehicle.  Electronic Control Unit (ECU) : An engine control unit (ECU), now called the power train control module (PCM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by reading values from a multitude of sensors within the engine bay or signals from other vehicle electronic control units through Controller Area Network (CAN), interpreting the data using multidimensional performance maps (called lookup tables), and adjusting the engine actuators accordingly. Modern ECUs use a microprocessor which can process the inputs from the engine sensors in real-time. An electronic control unit contains the hardware and software (firmware). The hardware consists of electronic components (ADC’s, H bridges, CAN Transceiver, MUX, Low side and High side drivers) on a printed circuit board (PCB), ceramic substrate or a thin laminate substrate. The main component on this circuit board is a microcontroller chip (CPU). The software is stored in the microcontroller or other chips on the PCB, typically in EPROMs or flash memory so the CPU can be re-programmed by uploading updated code or replacing chips. This is also referred to as an (electronic) Engine Management System (EMS). Engine control unit monitors/diagnoses the functionality of its Hardware I/O’s, Software algorithms & external interfaces and raises a Diagnostic trouble code (DTC) against a peripheral when it finds mal-functioning of that peripheral. Apart from logging a DTC, Engine Control Unit also alerts the user with MI Lamp / CE lamp Glowing/flashing. Engine Control Unit also conveys the information regarding Engine operating condition through Dynamic / Static Defined data identifiers.  Sensors : A sensor is a device that measures a physical quantity and converts it into an electrical voltage which can be read by an instrument or used by some controller for its purpose.  Actuators : An actuator causes an action (say injector open or close) based on command given by ECU.  Wiring Harness : Engine Wiring Harness and Vehicle Wiring Harness interface the Engine and Vehicle components to Engine Control Unit.