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Chevrolet Silverado 2014-Present: Why is My Check Engine Light On?

So the engine light turned on, but you don't know why. Read this guide to find out what's going on.

By Jerry Perez - June 29, 2015

This article applies to the Chevrolet Silverado K2XX (2014-Present).

The always pesky and always mysterious check engine light has turned on. But in the day and age where the Chevy Silverado has a sensor for everything, it could literally mean that your gas cap is off, or it could mean catastrophic engine failure is about to happen. The check engine light functions as a generic and universal warning light that could turn on for many reasons, but here is a guide for the top reasons why that light may be on in your Silverado. Remember that although it could be something simple, it's always worth making sure and you may have to visit your local dealer or repair shop.

Material Needed

  • OBD-II code reader

Step 1 – Check the gas cap

It could be off, or loose.

This is one of those issues that resembles the typical why won't my TV turn on, and the fix is it isn't plugged in. Well, one of the easiest as well as cheapest solutions for the check engine light is to make sure that your gas cap is on and tight. There is a sensor on the gas filler nozzle that detects the cap or its tightness. Save yourself an embarrassing trip to the dealer and a costly diagnostics check by first checking your gas cap. If the cap is off or loose, then tighten it, shut the engine off, and restart it. This should get rid of the light.

Figure 1. Check gas cap.

If the result of that process didn't fix the problem, move forward to the next step.

Step 2 – Check the EVAP system

There could be a leak.

The Silverado's EVAP system is in place to limit the amount of hydrocarbons released into the air. Because fuel fumes up inside the tank, it is allowed to exit the EVAP system in different methods. There is an EVAP vent solenoid that releases gases, then there is the purge pipe that goes to the block to be combusted, and the last one is the fuel filler tube where the gas cap is. If there is any abnormal amount of fumes or hydrocarbons exiting through any of these sources, it will trigger one of the many EVAP codes along with the check engine light.

EVAP codes could be:

  • P0440
  • P0455
  • P0442
  • P0446
  • P0443
  • PO449
Figure 2. EVAP system diagram.

If there were no stored trouble codes, it's time for a more visual examination.

Step 3 – Check engine sensors

The O2 or MAF sensor could be faulty.

The engine contains multiple airflow and oxygen sensors that dictate many important things that affect your engine's performance. These could also be reasons why the check engine light is on. Start by checking the MAF sensor located on the air intake of your Silverado. Sometimes, these may become dirty or grimy with time, so pull it out, clean it, and replace it. If it looks like it's in bad shape, it should be replaced. The oxygen sensor or O2 sensor could also be the cause for the check engine light. You can visit your local dealer or repair shop to get a code reading, and determine which sensor could be faulty.

Figure 3. MAF sensor.

Featured Video: Why is my Check Engine Light On?

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