by Thomas Buff

Created on: April 20, 2009

The Check Engine Light Why is that little light flashing on my instrument panel?

I am sure that many motorists have experienced the most common yet misunderstood problem with today's computerized automobile. Without prior warning a bright light illuminates your dashboard and sends chills up your spine. Do you pull over and call for assistance or do you continue to drive and deal with the stress of wondering if you are at this moment causing damage to your engine? Do you have to be an expert in automotive technology to decipher why this nagging little light is driving you crazy? This little light can be your best friend if you learn a little about how it operates.

The MIL or Malfunction Indicator Lamp is part of the on-board diagnostics systems required by EPA regulations on light duty vehicles and trucks to monitor the vehicles emissions related components. The MIL alerts the driver of a potential problem; in a nutshell it is an early warning system. The computer controlled warning lamps can cause confusion among vehicle owners due to its mysterious appearances and misinterpretations of its meanings. Although the correct name for the MIL is the Malfunction Indicator Lamp, it most commonly appears on the instrument panel as Check Engine or Service Engine Soon. The MIL is part of the system called On Board Diagnostics which began to be incorporated into every vehicle since the 1980's. The computer in your automobile monitors a complex data stream of information from numerous sensors in order to adjust everything from throttle position to air/fuel ratio. This process optimizes fuel economy, vehicle performance and emission levels. That is until something goes wrong.

In the case when a sensor sends a signal that is out of the normal range, the computer alerts the MIL and the driver is informed that a malfunction has been detected. A steady light indicates a fault that may cause high engine emissions and that a problem is present. Most modern computers can manage steady light malfunctions and will continue to operate the engine reasonably well. But this is not a signal to keep operating the vehicle for extended periods; it is a warning informing you that the problem needs to be corrected.

A blinking or flashing MIL indicates a severe level of misfire within the engine. This is a red flag that component damage will likely occur and the malfunction need immediate attention. Newer vehicles with OBDII (on-board diagnostics II) systems flash the MIL only if a computer identified problem is very serious. If this occurs, reduce your speed, avoid hard acceleration and have a technician check the vehicle right away to prevent costly repairs.

Automobile Technicians use electronic scan tools to communicate with the vehicles computer in order to retrieve diagnostic information. Many people assume that technicians only use these scan tools to find out what is wrong with the vehicle. The scan tools are helpful, but it also takes a close examination of electronic, mechanical, and physical components to repair today's sophisticated vehicles. Auto Technicians are trained to use technical information as well as their expertise for accurate diagnosis.

Remember; don't panic if the MIL comes on when you are driving. Many computer identified problems can be minor and easily repaired. One example is a loose gas cap. If you forget to tighten your gas cap it can set off the MIL. This is an emission malfunction and the computer will inform the driver that a problem exists via the MIL. Keep in mind that your automobiles on-board diagnostics and MIL are designed to keep your car running as safely and efficiently as possible, it is your friend.

Happy Motoring!

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