Why Is My Check Engine Light On?

January 4, 2023 Published by Leave your thoughts

You have just set out for a road trip, and suddenly, a yellow steady or flushing light shows up on your dashboard, telling you to check your engine. When you see this light, the first thing that flashes into your mind is that something is horribly wrong with your engine and that you should halt your journey.

However, the truth is that various problems might cause the engine to light, and some might be too minor to halt your trip. To help you, the automotive repair professionals from M & M Tire & Service Center have shared reasons why your check engine light is on and how to diagnose check engine light issues. Check them out.

Causes of the Engine Light

“Why is my check engine light on?” is a common question among many vehicle owners/drivers. If you are one of such, below are the most likely culprits to look up if you encounter the problem.

Defective Oxygen Sensors

The oxygen sensors are a part of the fuel and emission systems. They monitor the oxygen level in the exhaust and relay the information to the car’s Electronic Control Unit (ECU), which, in turn, optimizes the air-to-fuel ratio. 

When defective, the sensors may feed the ECU with the wrong information. Consequently, this may interfere with the optimal operation of the engine, causing problems like excessive oil consumption, damage to spark plugs, etc. hence the check engine light.

A Defect in the Evaporative Emission Control System

A typical EVAP emission control system prevents gasoline emissions from escaping into the atmosphere. It comprises a fuel tank, gas cap, fuel tank pressure sensor, EVAP canister, separator, and series of valves and tubes. A slight leakage or damage in any of these components can trigger the ECU to display the engine light.

Damage in the Catalytic Converter

As the name suggests, the catalytic converter changes nitric oxide, hydrocarbons, carbon monoxide, and other harmful compounds in the car’s exhaust gases into less toxic compounds like carbon dioxide and steam. When defective, the catalytic converter won’t work, and the ECU will detect the problem and cause the engine light.

The catalytic converter is likely to go bad if there is a problem with the spark plugs, oxygen sensor, fuel injector, check valve, sticking float, or due to incorrect timing. That’s why you need the help of a professional to address the engine light problem.

Misfiring Problem

Another cause of engine light is a misfiring problem. It can result from vacuum leaks, defective spark plugs, failed ignition coil, bad compression, failed fuel injector, and leaking seal/gasket, among other causes. 

The leading sign of misfires in your car is reduced performance, like poor power transmission. The problem can also cause engine failure if not addressed in time.

How To Diagnose the Check Engine Light

The car’s ECU memory keeps a Diagnostic Trouble Code when the engine light pops on your dashboard. So, the most effective way to troubleshoot the cause of the engine light is to use a code reader to scan for the code. However, the diagnostic code may only point to one problem, which might have several other causes. 

For instance, the code reader might display a diagnostic code P0300 to signify a misfiring cylinder problem in your car when the problem might be coming from the emission system, failed catalytic converter, or defective ignition coil. You need the help of a professional to identify and repair the problem.

Work With a Reputable Car Repair Center To Get You Car Back on the Road

Do not go beyond the M & M Tire & Service Center when finding a car repair centerAt M & M Tire & Service Center, Texas, we have been offering all types of automotive repair services since 1975. Our services include: 

  • Engine light diagnosis
  • Auto repair
  • Computer diagnostic
  • Engine repair
  • Auto electric repair
  • Clutch repair
  • Engine oil changes, etc

We are open from Monday to Friday from 8 a.m. to 6 p.m. Please contact us today to book an appointment for your vehicle. 


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