There are numerous reasons why a check engine light comes on because this light serves as a catch-all for engine problems that do not have lights or gauges of their own. Things such as an engine vacuum leak or a faulty engine control module will turn on the check engine light. Mechanic One Auto Repair & European lists the other common reasons why a check engine light comes on below.
Clogged Catalytic Converter
The catalytic converter can become clogged at about 60,000 miles to 90,000 miles. When this happens, your check engine light will come on and you may smell an odor that reminds you of rotten eggs. You may also end up with an overheating engine.
Loose Fuel Cap
The fuel cap that covers the tank is designed to create a seal so fuel cannot evaporate out of the tank. If the fuel cap is not screwed on tightly or the seal has broken, your check engine light will come on. There is a sensor there that tells the engine control module that the fuel tank is sealed.
Malfunctioning Mass Airflow Sensor
Another common reason why the check engine light turns on is a malfunctioning mass airflow sensor. Also called the MAF sensor, if this sensor gets dirty, which can happen due to its location behind the air filter, it will start to malfunction and you will end up with a check engine warning on the dashboard.
Malfunctioning Oxygen Sensor
The oxygen sensor generally lasts about 100,000 miles, but it can fail prior to this. If it does, the check engine light will turn on and stay on until you replace the faulty O2 sensor. This sensor is located in the front of your tailpipe so it can measure the oxygen levels in your vehicle’s exhaust.
Oddly, your automobile’s transmission does not have a warning light of its own. Therefore, if there is something going on with the transmission that isn’t right, the engine control module may turn on the check engine light. You may also experience problems getting your vehicle into gear or issues with the vehicle shifting through the gear cycle.
Worn Spark Plugs
Finally, another common reason why the check engine light comes on is worn spark plugs. Today’s spark plugs can last 100,000 miles before they need to be changed. Once they begin to wear out, however, your engine will misfire and you will have a check engine warning.
Call Mechanic One Auto Repair & European in Canton, MI, today to set up an appointment for your vehicle if your check engine light is on.