Oh no. The check engine light pops on again.
What’s the biggest headache when you drive back home after a long day work? No doubt there is nothing more frustrating than the check engine light is on. You cannot help asking yourself why. However, there is no explanation, just like the baby crying. It is very difficult to figure out what the check engine light is trying to tell you. However, before spending a lot in the shop for repairs, you need to have an understanding of the common reasons why the light is on.

Reason No. 1: Faulty O2 sensor
The oxygen sensor takes care of measuring the amount of oxygen in the exhaust. When you push down on the accelerator, the sensor will send out a signal to the engine’s computer telling either add or reduce the of fuel. If there is something wrong with this part, you will find that it’s difficult for the car to pick up the speed.

Reason No. 2: Loose gas gap
We all know that a lot of cars have sensors around the gas tank. It will go off when there is too much or too little pressure in the tank. In this way, if you did not tightened the gas gap in the right way, there is little pressure which will leave the sensor turn off.

Reason No. 3: Sticky EGR Valve
The exhaust gas recirculation valve (EGR) aims to reduce exhaust emissions by recirculating exhaust gases into the engine's intake stream. This process reduces nitrous oxide formation because the gas displaces some of the intake charge and cools down the combustion system. If this valve gets clogged with oil or dirt, or it starts to deteriorate, you might notice a strong smell of gas every time your start the car; this will also set off the Check Engine light.

Reason No. 4: Clogged fuel injector
You should know that in daily use, the fuel injector could be clogged with dirt and oil. In this case, the gas isn’t getting to the combustion chamber in the right way. This would be the reason why check engine light is on. If you haven’t had the fuel system cleaned for a long time, you can do it now to prevent from the flashing check engine light and the expensive trip to the repair shop.

Reason No. 5: Bad spark plugs
Spark plugs take the big responsibility in the whole car, transferring heat from the combustion chamber and igniting the fuel and air mixture into the engine. However spark plugs tend to burn out. Even if the spark plug wires are slightly worn out or the plugs get a little old, it will result in misfire and cause the check engine light to turn on.

So if the check engine is on next time, maybe you can check by yourself in accordance with the above instruction. But most cases are out of scope and you still need to go to your mechanic. Even so, knowing the checking engine code that made the light pop on will help you avoid getting ripped off and may save you a big check. Thanks to the technology, it’s an easy job to do this. Autointhebox(http://www.autointhebox.com) recommends you a money- and effort-efficient tool, Autel MaxiDiag Elite MD802(http://www.autointhebox.com/autel-maxidiag-elite-md802_c105). It enables the user to not only get into the enhanced OBD-II system with mode 6 access, live data and graphing, but it also allows you to scan the entire car. Just push one button, you can read and clear codes in all Powertrain, Chassis, Body, and Information & Communication systems.
From now on, there is no OMG when seeing the check engine is on.