All You Need to Know About Car ECU

Car tuning is very popular in UAE where they love racing and have special carts for that. When we talk about tuning an engine, we are talking about the car’s ECU. 

ECU is the smartest piece of your car, but don’t worry you will not be wondering “ should I sell my car in Dubai because I have a faulty ECU”. After all, its repair is easy and not that much costly.

But be aware: You should never attempt to repair the ECU! 

What Is the ECU in a Car?

The ECU (Electronic Control Unit) is the brain of the engine, so it is vital in every car.

While driving, this unit is always collecting information to control other components. 

Using a wide array of electronic sensors, chips, and components in the vehicle, the ECU can provide feedback to the engine. The nature of this feedback will determine the function the motor will perform next.

It helps a lot in calculating the proper amount of air and fuel needed for the internal combustion process. In this way, better energy efficiency can be achieved.

The Idea Behind ECU

Before the invention of engine controllers, car manufacturers used a carburetor to control the air-fuel mixture. 

However, this technique had a big drawback: the system is static. manufacturers had to find an ideal fit for all circumstances: cold or hot, wet or dry, economical driving, or just a lot of torque

They wanted to find a good mix of fuel consumption, emission values, and power. A mix ​​that would work under all circumstances. 

And the ECU came up as the solution! 

It was the solution that can adjust the mixture ratio, and thus always ensure the best fuel injection.

Optimal Fuel Injection

Optimal fuel injection is about consistency in the amount of oxygen and fuel. 

If there is too little oxygen, not all the fuel burns, thus there is a power loss. And the other way round, too much oxygen also leads to a power loss.

The optimum burn rate for complete combustion is 14.7: 1 i.e we need 14.7 grams of air for one gram of gasoline. 

Unfortunately, this ratio is not suitable for all situations. Most cars have a 12.5: 1 ratio and the most economical vehicles have a 15: 1 ratio. Therefore, the task of the ECU is to estimate which ratio is better at a given moment.

ECU Input

To control the fuel injection, the ECU processors need to receive information from many sensors. Some of the most important sensors that provide information to the engine controller are: 

  • Map sensor

The electronic system of a combustion engine uses a Manifold Absolute Pressure Sensor (MAP Sensor). 

The MAP sensor, or boost pressure sensor, measures the air intake pressure thanks to its resistors. 

It is mainly for Diesel vehicles with a turbocharger but also certain gasoline cars have it. The sensor transmits signals to the engine control unit, which uses it to adapt the fuel injection.

  • Coolant temperature sensor

What the coolant temperature sensor does speaks for itself. 

This sensor determines the operating temperature of the engine. Depending on the information from the sensor, the computer adapts the injection time and the ignition angle to the operating conditions.

  • Lambda sensor

Or the oxygen probe. The lambda sensor is an anti-pollution device that also allows you to reduce your fuel consumption. It helps the computer to determine the best ratio of air and fuel for engine combustion.

  • Crankshaft position sensor

The crankshaft position sensor, along with a camshaft sensor, measures the relationship between pistons and valves in the engine. This is especially important with variable valve timing engines.

The camshaft sensor is essential for your engine and for starting your vehicle. In particular, it plays an essential role in the injection system and the combustion cycle of your engine.

  • Knock sensor

The knock sensor analyzes any engine vibrations. For each vibration, it sends an electrical signal to the Electronic Control Unit (ECU) which will be able to advance or delay the ignition to suppress them and thus optimize the operation of the engine.

From Input to Output 

In addition to the direct sensor signals, the CAN network transmits many pieces of information.

With all of this information, the ECU unit must know what information is important at that time to take an action next. 

The CAN filter plays an important role in this regard. As the name suggests, the CAN filter separates important information from slightly less important ones, and then sends it to the processor in the ECU. 

This processor converts the input information into output information after numerous calculations. 

ECU output

The generated output information goes then to different parts of the car. The information flow depends a lot on the type of car. 

For cars with a turbo injection engine, for example, the ECU can send information through the CAN network to the turbo-actuator. 

Although ECU remapping is safer than mechanical engine tuning, it affects the market value of your car. 

However, as mentioned earlier, the most important function of the ECU is optimum engine performance through computer-controlled fuel injection.

Top 5 Causes of Car ECU Failure

The ECU regulates virtually all important systems and functions in your vehicle. If you were to have a bad ECU, many noticeable symptoms would manifest. It wouldn’t take you long to realize that you have a faulty ECU.

However, you might be wondering why the ECU malfunctioned in the first place. Many internal causes could contribute to this.

  1. Dead battery

Car batteries have electronic cells that must be working for the ECU to work. If any of the cells in your car’s battery are dead, your ECU will fail shortly thereafter. Once all the cells are dead, your entire vehicle will no longer be able to function.

You won’t even be able to start your vehicle and run the engine. So, look for the warning signs of a faulty ECU, then have your battery examined immediately.

  1. Corrosion

The ECU is surrounded by gaskets to prevent moisture from getting inside. However, after several years, these gaskets tend to wear out. If the gaskets become too worn, it will be easier for moisture to pass through them and enter the ECU.

  1. Low voltage

The average ECU should have at least 9 volts, but preferably 12 volts. There is wiring that runs in the ECU harness where you can check the amount of voltage.

  1. Bad start

Anytime you quick-start your battery, you need to make sure that the jumper cables are properly connected. If you start with the cables incorrectly connected, this could short-circuit your computer by causing it to prick too quickly.

  1. Bad starter

Many vehicles have starters with their sensors. One of these sensors is the priority sensor which manages the number of volts the ECU will receive.

If this sensor went faulty, the ECU would not receive the correct amount of voltage. This could then malfunction and cause other problems in your vehicle.


TBN Editor

Time Business News Editor Team