My service engine soon light is on?

Hello,

Service engine light can come on for various reasons. First you want to make sure you have plugged in everything. Specially the mass airflow sensor as usually you will have to take the intake tubing off for easy access to the plugs.
Any thing left unplugged can trigger the engine light.
It could even happen if one of coil wires are loose.

Check out this video of spark plug replacement of these GM vehicles:

https://youtu.be/H7fnj0GyqYs

Also you will want to get the vehicle scanned for codes.

Here is a helpful videos shows how to proceed to retrieve codes:

https://youtu.be/vMwTzURWXmk

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

https://www.2carpros.com/articles/how-a-mass-air-flow-sensor-works-maf

Please let me know what you find out.

Thank you.