The check engine light illuminating is often accompanied by a sense of dread as you anticipate an expensive repair. The problem could indeed be due to a bad catalytic converter that requires an expensive repair, or it could be as minor as a loose gas cap. Often, it necessitates visiting your local mechanic to discover the precise defect.
When there is a malfunction, the car’s computer gives an indication by switching on the Check Engine light, also known as the Malfunction Indicator Lamp (MIL). A single light can’t tell us too much about the exact issue at hand, however.
Early engine diagnostic systems before 1996 were specific to carmakers, mainly for compliance with the pollution-control requirements of the Environmental Protection Agency. From 1996 onward, all carmakers had to use a standardized protocol called OBD-II, which had a common list of diagnostic trouble codes (DTC). A universal connector, conveniently placed under the steering column, allows access to the code information.
Understanding the Code
There are a few hundred generic codes and thousands of power-train specific codes.
You can get the code information yourself by buying a code reader from a car parts store, connect it to the onboard diagnostics (OBD) port and decode using websites like Engine Light Help. Some code readers may help you to switch off the Check Engine light without repairing anything, but this may be shortsighted.
The “service required” light on the gauge cluster and the Check Engine light may cause confusion among drivers. They no connection with each other. The “service required” light indicates a need for oil replacement or some other routine provision. The problem indicated is not as severe as that signaled by the Check Engine light.
Different manufacturers provide check engine lights in various colours like orange, yellow or amber. Major problems usually mean the Check Engine light will flash, signaling you must get the car checked immediately.
Top 5 Reasons for a Check Engine Light
- A failing oxygen sensor needs replacement
- The exhaust system requires checking
- Spark plugs or plug wires need replacing
- The mass airflow sensor has failed
- The gas cap is not fitted correctly
What Should I Do When the Check Engine Light Comes On?
When the check engine light switches on, it may blink or remain uniformly illuminated. If it is blinking or changes colour from yellow to red in some vehicles, the problem requires urgent attention. In both cases, a mechanic must check the car.
In the latest car models, a blinking light is normally due to an acute misfire, causing unburned fuel to enter the exhaust system, with the risk of damage to the catalytic converter. This can really cost a great deal to repair. In this situation, you should first reduce power and take the vehicle for a check immediately.
A steady light means that there is no emergency as such, but you still have to repair the vehicle at the earliest opportunity. Present day car computers are programmed to correct the problem to maintain performance level, but the mileage may reduce and pollutants and hydrocarbons emission levels may increase alarmingly.
In certain exceptional cases, the car computer will automatically reduce available power to protect the engine.
Try to locate any problem that must be corrected urgently. This includes checking of your dashboard lights and gauges to see if the oil pressure is low or there is overheating. Shut off the engine at a safe place.
You can also tighten the gas gap. This may correct the problem in many cases. The light will reset only after a few trips. In some vehicles, a loose gas cap may be signaled by a separate indicator.
You should reduce speed and load. Take the vehicle for inspection immediately to avert further damage and expenses.