If you disconnect your battery to reset your check engine light. You may erase valuable memory from the computer and wind up disabling your car stereo and factory installed alarm.

First, why is your check engine light on? The check engine light or service engine soon light is directly connected to your car’s computer and monitors the emission system. This warning light was federally mandated by our government to notify the driver that the vehicle may be polluting the atmosphere.

The check engine light is all about the war on pollution, global warming and smog. One of the main problems with this emission system-monitoring device is that it is very sensitive. Often you will find that this light is illuminated for a minor malfunction or even an intermittent problem.

This is why the first step in the solution to the problem is to clear the code and retest the vehicle to see if the light returns. The problem with this is that the fastest way to reset the check engine light is to disconnect the battery. But there are many systems in your vehicle that require constant battery power.

Most people do not realize that your vehicle computer adapts to your driving habits. Your vehicle computer stores memory functions such as shift points, idle speed and throttle position for the primary driver. When you disconnect the vehicle battery you wipe out this memory and the computer returns to a default mode, which may make the vehicle run in a manner that you are not accustomed to.

Other complications that may arise from disconnecting battery power to your vehicle may include that the radio will not work after you reconnect the battery. Most vehicles today have theft protected radio systems. When you disconnect the battery the radio thinks that it is being stolen. Re-activating the radio can be a lot of trouble, and in most cases includes obtaining the code from the vehicle manufacturer to reactivate the radio.

Another common problem you may run into by disconnecting power from the vehicle is that many vehicles today have a factory installed alarm system. When power is removed from the system. The vehicle can go into a lock down mode to prevent engine startup in case the vehicle is being stolen.

It is a very common problem today to have your check engine light pop on for little or no reason. Every vehicle owner should learn how to reset the check engine light for this reason.

The best way to handle the reset of the check engine light is to purchase an auto scan tool and clear the code without disturbing the battery connection. Automotive scan tools have really come down in price and make this the best way to approach the problem of resetting the check engine light.

Turning off the check engine light with an auto scan tool requires no technical experience and is very easy to accomplish. After the reset the check engine light procedure is performed if the light stays off you have just fixed car in less than 10 minutes. If the light does come back on you now have the knowledge necessary to get the problem repaired quickly and easily.

Mark R. Gittelman has 23 years in the automotive business. Mark is also an ASE certified master technician and provides a website filled with free information about the automotive world. Visit his