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Engine light blinking

J Hawkins
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J Hawkins New Member

J Hawkins

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I drive a 2015 tahoe. When I accelerated the engine light started blinking then went off within minutes. What does this mean? 

JimCost2014 Senior Enthusiast

JimCost2014

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On 7/26/2021 at 8:55 AM, J Hawkins said:

I drive a 2015 tahoe. When I accelerated the engine light started blinking then went off within minutes. What does this mean? 

Welcome to the site.

 

Answer to your question is not an easy one:

 

Blinking Check Engine Light Diagnosis:  Chevy Silverado

There will always be trouble codes associated with the check engine light blinking.  These trouble codes will be able to tell you where to start hunting down the problem.  Here are the most common issues that end up causing the check engine light to flash.  But, follow the OBDII codes.   A code scanner is cheap.  Use it to find out exactly why your vehicles computer decided to flash this light.

 

Silverado Check Engine Light Flashing Due to Ignition Issues

The ignition system is the most common reason that the check engine light will flash.  The ignition system consists of spark plugs, plug wires, and the ignition coil packs (older vehicles have a distributer that has the same function as coil packs).  These parts work in concert to ignite the fuel in the combustion chamber at just the right time.

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  • P0300:  Random Multiple Misfire–  This is one of the most common codes that is thrown when the engine is misfiring.  It means that the engine has a misfire, but the computer can’t detect which cylinder that it’s coming from.  This code is often thrown when there is a fuel issue, or a timing issue, and not just bad ignition components.  That is unless all the cylinders share a common coil (distributor ignition). 
  • P0301-P0312:  Cylinder Specific Misfire-  These trouble codes correspond with a specific cylinder misfiring (cylinder number corresponds with its place in the firing order).  Although it’s a bad sign when the service engine soon light flashes, when one of these codes comes up with it (and nothing else), it’s almost always one spark plug or ignition coil.  There can be other reasons this code is thrown, you can see more by clicking on the P0301 link above.

There are other misfire related codes as well, but those are the most common ones.

Chevy Silverado Blinking Check Engine Light Diagnosis

Fuel System Issues 

Keeping in mind that any engine needs air, fuel, and spark for ignition, your Chevy Silverado’s fuel system can often cause the engine to misfire.  It can run too lean or rich.  Alternatively, there may not be enough fuel for proper combustion, or the fuel isn’t atomizing properly. 

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  • Fuel Mixture:  If the engine is running rich or lean, the engine will misfire and throw the fuel mixture related codes, such as P0171, P0172, etc..
  • Injector Issues:  A bad fuel injector(s) can cause a misfire.  If the fuel can’t atomize properly, the engine will misfire.  Here’s a good article on how to diagnose whether your fuel injectors are bad from procarmechanics.

 

Other Issues:  Flashing Check Engine Light- Chevy Silverado

While a majority of the time, the flashing check engine light is going to be caused by a misfire related to your Silverado’s ignition system or fuel system (as stated above), there are other issues that can cause it. 

  1. Your timing chain could have jumped. 
  2. If you have VVT, it may be having issues. 
  3. EGR- The EGR system recycles burnt exhaust gasses back into the combustion chamber.
  4. Crank/Cam Sensor-  When the cam or crank sensors are not being read by the ECM/PCM, it’s impossible to get the ignition timing right.  If you Silverado does start at all, it’ll run rough.
  5. It could be a more serious mechanical issue, such as as bent valve, bad lifter, etc….

 

Conclusion

We recommend that you don’t drive your vehicle if at all possible until you diagnose and fix your Silverado’s flashing check engine light.  Just pretend that it’s letting you know that it’s going to cost you way more money to fix the problem if you keep driving it.  If there is anything that you would like to add, please feel free to leave a comment below.  Good luck!

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