The check engine light (CEL) covers all engine problems and some do not have their own individual warning lights. Mad Hatter Auto Repair can run a diagnostic test to find out why your check engine light is on. You may not know this but the check engine light was recently tested to see how effective it is in reporting engine errors. The light passed the test with flying colors. Therefore, it’s crucial that you take a Check Engine Light warning seriously.

Catalytic Converter

One exhaust system part that can cause a check engine warning is the catalytic converter. If it gets clogged, the exhaust will back up into the combustion chamber. This can create problems with engine performance and cause system sensors to report error codes to the engine control unit.

EVAP Control System

The EVAP control system is installed in your vehicle to make sure that the gasoline or diesel fuel never evaporates out of it. If this system malfunctions, you will end up with a CEL warning and engine performance problems. Even a loose gas cap can turn on the check engine light.

Engine Control Unit

We mentioned above that the engine control unit turns on the CEL. This is because this unit is your vehicle’s main computer chip. In fact, it will even turn on the check engine light if it is malfunctioning. Aside from the warning, your engine will also stop running.

Mass Airflow Sensor

The mass airflow or MAF sensor can also trigger a check engine warning if it malfunctions or gets too dirty. Aside from the illuminated dashboard light, you will start to have engine performance problems. Unfortunately, these problems will reduce your vehicle’s fuel economy.

Oxygen Sensor

The same is true with the oxygen sensor, which is another exhaust system part. Also called the O2 sensor, this sensor can malfunction at about 100,000 miles. When it goes bad, it will alert the engine control unit that it is having problems and the unit will turn on the CEL.


It seems as if the transmission should have its own warning light, doesn’t it? Unfortunately, it does not, so the engine control unit turns on the check engine light on the transmission is malfunctioning. You may also notice problems with the gear shifting in your automobile.

Mad Hatter Auto Repair will diagnose and fix your issue.

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