Why is My Check Engine Light On? Diagnostics Explained for Palmerston Residents

Close picture of the check engine light | CDP Diesel & Auto

As you drive down the road, a glow catches your attention. You look down and notice that the pesky check engine light is on. With a resigned sigh, you turn the music down and start listening for who knows what. All you can envision is dollar signs. The check engine light is not always indicative of expensive repairs, but it is something that you should promptly address. At CDP Diesel & Auto in Palmerston, ON, we will diagnose and repair the problem, getting you back on the road quickly.

How a Check Engine Light Works

An electronic control module, or ECM, manages emissions and other engine functions. When the ECM detects an out-of-range reading, it attempts to correct it. If the readings do not come into range, the ECM stores a fault code and illuminates the check engine light to alert you there’s a problem.

Common Reasons for a Check Engine Light to Come On

The check engine light can illuminate for various reasons – our diagnostic tech at CDP Diesel & Auto uses a computer to interface with the ECM to determine the codes and diagnose the problem. Common reasons include:

  • Fuel Cap: If the fuel cap is loose or damaged, it allows air into the system. This triggers a code for the evaporative emissions system. A technician must determine whether the issue is with the emissions system or the gas cap.
  • Oxygen Sensor: The ECM can throw several oxygen sensor codes, including malfunctioning O2 heater codes. Generally, when the oxygen sensor code pops up, it’s because the amount of unburned fuel in the exhaust is too high or too low. The code could also mean there’s a problem with the sensor itself or the wiring to the sensor.
  • Mass Airflow Sensor (MAF): If the MAF malfunctions, it causes the air-to-fuel ratio to be incorrect. The vehicle may burn too much fuel or not enough. If it is burning too much fuel, you will probably see black smoke coming from the exhaust.
  • Spark Plugs: Ignition system issues are some of the most common reasons the ECM stores a code for the oxygen sensor. If the spark plugs or other components in the ignition system are not working properly, you may have too much unburned fuel in the exhaust.
  • Exhaust Gas Recirculation: This part of the emissions system circulates exhaust back into the engine to minimize emissions. If this system malfunctions, your vehicle is putting excess emissions into the atmosphere.
  • Knock Sensor: This is a serious fault. You may not hear the engine knocking or pinging, but the ECM does. Generally, it’s not the knock sensor malfunctioning – it’s the knock sensor doing its job and letting you know that there is something wrong with the air and fuel mixture and processing. Engine knock can damage the engine’s internal components.
  • Throttle Positions Sensor: If the throttle position sensor fails, the vehicle won’t run right, if at all. This sensor tells the computer how far you are pressing on the accelerator.
  • Coolant Temperature Sensor: This sensor tells the computer what the engine temperature is so it can turn the fans on or off. The sensor is separate from the sender, which tells you the engine’s temperature via a gauge. If you leak all of the coolant, the sender will not work, as it doesn’t have anything to read.

If the ECM malfunctions, it cannot diagnose itself and may store several unrelated or nonsensical codes. Our techs must manually test the ECM to determine if it has failed.

Contact CDP Diesel & Auto in Palmerston ON, Check Engine Light Diagnostics

Your vehicle’s check engine light is more than just a simple indicator; it’s a signal from your car’s brain that something isn’t right. Whether it’s a minor issue or a precursor to a major malfunction, prompt attention can make a difference in the longevity and performance of your vehicle. Driving with unresolved issues can not only decrease your vehicle’s efficiency but can also lead to more expensive repairs down the road. Remember, it’s always best to entrust the diagnostics and repair to experts who have the tools and knowledge to pinpoint the root cause accurately. So, the next time that check engine light shines, take it as a nudge to visit the trusted professionals at CDP Diesel & Auto in Palmerston.

Contact CDP Diesel & Auto at (519) 418-3344 or email [email protected] to set up an appointment. We are conveniently located at 114 Noble Family Road, Palmerston, ON N0G 2P0, Canada.


Experience Top-Notch Diesel Repair Services in Palmerston, ON

Regardless of why your truck breaks down, it’s always a hassle. You’re down a truck that you might need right now. But at CDP Diesel & Auto, you don’t have to worry about such things.

Whether it’s preventative maintenance or you need major engine or transmission work, we’ll get you back on the road as quickly as possible—all with five-star customer service, honesty, and integrity.

Contact CDP Diesel & Auto at (519) 418-3344 or [email protected] for an appointment. Our diesel repair shop is conveniently located at 114 Noble Family Road, Palmerston, N0G 2P0, Canada.