371 W. Patrick St. | Frederick, MD 21701

371 W. Patrick St. | Frederick, MD 21701

Frederick, MD Diagnosing Engine Problems That Elicit the Check Engine Light

Diagnosing Engine Problems That Elicit the Check Engine Light

Diagnosing Engine Problems That Elicit the Check Engine Light

What to Do When Your Check Engine Light Comes On

Whenever the check engine light comes on, it is often accompanied by a feeling of dread in anticipation of the coming auto repair bill. However, there are many reasons the check engine light may come on. The problem may be a simple adjustment that you can make yourself or it may require professional service. In any case, it usually entails a visit to an auto repair shop. The purpose of the check engine light is to warn of a malfunction in the engine. Before 1996, automotive manufacturers had their own diagnostic systems to ensure cars met EPA standards. In 1996, a universal protocol called OBD-II was introduced, which included standardized diagnostic trouble codes (DTC). It requires all cars to have a connector from which this information can be retrieved. The access port is typically found beneath the steering column.

Common Causes for Check Engine Light Coming On

Unless your car is exhibiting signs of a major problem such as stalling, transmission slippage or smoking, the check engine light is usually no cause for immediate concern. The light may come on when various engine components are beginning to wear and need replacing. It is important, however, not to ignore them since failure to correct the problem can cause greater fuel consumption, decreased performance and lead to wear or malfunctioning of other engine components. Below are some of the most common reasons the check engine light comes on.

  • Loose gas cap
  • Oxygen sensor needs replacing
  • Spark plugs are worn
  • Mass airflow sensor needs replacing
  • Catalytic converter is damaged


What to Do When the Check Engine Light Comes On

Diagnosing Engine Problems That Elicit the Check Engine Light

The check engine light may come on for minor malfunctions that you can remedy for little or no cost. If there doesn’t appear to be a major problem with your vehicle and the light comes on, inspect for minor issues such as a loose gas cap or worn spark plugs. Once you have made adjustments, the check engine light will still be on. Many vehicles require restarting three times with no errors to clear the code. Alternatively, most code readers are capable of clearing the trouble code. This is not recommended unless you are sure the repair has eliminated the problem. In addition, there are some conditions that can cause the check engine light to come on when no problem exists. In this case, the light should go off on its own in a short time.


Interpreting Code Readers

A variety of code readers can be found on the market, from inexpensive to sophisticated models. Hand held code readers available at most auto parts retailers can provide information that may help you avoid an expensive repair. Nonetheless, interpreting the codes can sometimes be confusing. For example, the code reader may indicate the light has come on due to an engine misfire. However, an engine misfire can be caused by a fouled out spark plug, malfunctioning fuel injector or a bad coil pack. For more complete information about the trouble code, a professional engine diagnostic is required.

What Are Engine Diagnostics

Engine diagnostics are performed by a professional mechanic. Your car is connected to a computer interface to return the problem codes, similar to that of a code reader. The engine diagnostic equipment at an automotive service center is much more sophisticated and may return multiple codes. The mechanic will use the information provided from the codes as well as the car’s performance to diagnose the problem. The diagnostic equipment used at a professional automotive repair shop is quite expensive. When you pay for an engine diagnosis, it covers the use of this equipment as well as the expertise of the mechanic. A thorough engine diagnosis can pinpoint the problem precisely and eliminate the cost of replacing unneeded parts.