Electronic Control Unit (ECU)
The Electronic Control Unit (ECU) is the brain of the vehicle; it is also called the brainbox. It is responsible for the processing of information, sending instructions and management of the various components and systems in the vehicle. The ECU is a computerized device (it is the vehicle’s computer) that receives electrical signals from various sensors in the systems and components all over vehicles, it also send instructions to the various actuators in the vehicle for the overall control and management of the vehicle.
The ECU is responsible for the control of the ignition system as it controls the ignition coil for igniting the spark plugs and also the injector for supplying of fuel to the combustion cylinder for combustion processes.
Sensors are devices that convert mechanical, sound, light, chemical and electrical energy to electrical signals which can be interpreted by the ECU (the vehicle’s computer) to pass certain information.
Actuators are devices that start or turn on a system or component in the vehicle. Actuator can receive electrical signals from the ECU and interpret it as instructions.
The ECU controls almost all systems and components in modern vehicles of which is the Immobilizer. Car doors, Keys and locks in the vehicles are all programmed also; these devices have in-built chips that can be programmed. So when a message is sent through these devices the ECU receives such messages, interpret them and send instructions to the actuators in the concerned components or systems.
Apart from the ECU there are other computerized processing units in the vehicles, especially for modern vehicles such as Signal Acquisition Module (SAM), Immobilizer (also called Transponder Key ECU) etc. these units/devices also perform computerized processing and instructing procedures. The immobilizer is also responsible for the processing and control of the vehicle’s security system.
Due to the fact that the Car key or remote and the doors and locks including the Ignition lock are all computerized and programmed with the immobilizer (i.e. Transponder key ECU), it therefore signifies that only a key with such unique set of programming can unlock or access such system, thereby enabling better security of the vehicle.
Basically during key reset or replacement what occurs is usually reprogramming of both the key (including the immobilizer) and the ECU to tally. This is done with a diagnostic scanner with immobilizer reprogramming features or an immobilizer reprogramming tool.
The ECU which is Electronic Control Units, this is a computerized system which have all the Control units in the car. It means all the system which has the control over various sensors and actuators in the vehicle.
Get our free resources such as books and courses.
Sensor and Actuators – ECU
Before I continue on ECU, let me talk about Sensors.
Sensors are devices that convert mechanical energy from different parts and component of the vehicle to electrical energy or signals. They send electrical signals from various components of the vehicle to the computer inbuilt in the car (ECU) whenever such system is not in normal working condition.
Sensors are located in almost all parts of the car, old cars usually have sensors in the Engine and Transmission, but modern cars have in all parts including wheels, lights, doors, body, seats and more.
The more the sensors the more electronics system in the car, that is why almost all parts of modern cars have electrically connections and devices.
These sensors send signals to the ECU; each sensor signal is unique as it is interpreted as a code (fault code) which brings us back to the previous lessons. Also each component that has a sensor also has its own code.
This quality of interpretation (i.e. information) of signals provided by the diagnostic tool is what makes a diagnostic tool superior to others.
The diagnostic computing system (I.e. ECU) receives signals through Controller Area Network (CAN) and processes it for interpretation for a diagnostic tool. Get your Electrical Diagnostics tools here.
More on ECU
Now back to ECU, the size of the ECU depends on the numbers of System (group of components that works together to perform a single function) in the car. Old cars can have about fifteen Control Units, but modern cars can have up to ninety Control Units. Examples of control unit are Transmission, Motor Electronics, Telematics, Fuel pump, etc.
ECU which is Electronic Control Units, these are all the Control Units in the car. It means all the system which has the control over various sensors in the vehicle. The ECU is responsible for controlling various systems and component in the vehicle especially those that are computerized and electronically or electrically programmed.
The management, governing and diagnostics of the engine are controlled by sensors and actuators which are controlled by the ECU. The Ignition system, the fuel system, cooling system, electrical system and electronics are also controlled by the ECU, it controls their operations.
The ECU is computerized to allow reprogramming to suit various adjustments in the engine system.
Faults Associated with ECU.
The ECU may develop software fault causing the vehicle systems and components to malfunctions, in this case the ECU can be reprogrammed using a diagnostic tool. Also if it is a hardware fault the ECU can the replaced or repaired by an electronics expert. A faulty ECU can be diagnosed using a diagnostic tool or when irregular and random faults are being displayed by the vehicle especially the engine when everything seems to be working properly.
A faulty ECU may cause serious problems to the vehicle especially the engine. Some of these problems or faults include:
Multiple misfiring.
Low and unstable RPM.
Engine not cranking.
Limp mode activation.
Wrong fault codes and warning light pop up.
None supply of fuel to the engine.
None spark from spark plug.
Programming, Repair and Replacement.
The ECU can be fixed either by reprogramming, repairing or replacing it.
ECU REPROGRAMMING: ECU can be reprogrammed using diagnostic tool with ECU reprogramming features. The diagnostic tool is connected to the OBD port and it is reprogram with a passcode which is generated by the manufacturer or its agent, this passcode is usually generated by imputing the vehicles VIN (Vehicle Identification Number) and it is a charged service. Get your ECU and auto parts replacement here.
ECU REPAIRING: The ECU is an electronic system with various electronic circuits and component, repairing of the ECU can be done by an electrical electronics engineer with experience in ECU repairs and reprogramming. It involves replacing any bad component in the circuit or reprogramming any component to suit the vehicle’s configuration.
ECU REPLACING: The ECU is replaced when it cannot be repaired or reprogrammed. When the ECU is replaced it must be reprogrammed with the immobilizer (transponder key ECU) and the key in order to start up the engine.
HOW TO KNOW A FAULTY ECU
Fault codes indicating it may appear.
It show wrong warning lights and error codes in components that are in good state, that is it just misbehave giving wrong information.
The vehicle may not start even when everything electrically and mechanically seems okay.
Engine misfiring randomly or continuously.
