Computer codes and check engine light

Hey, could you help me? I have a 1999 Toyota 4runner 2WD 3rd gen.
There is a device beneath the passenger-side glove compartment close to the passenger's feet. This could be an electrical/software device. I could not unloosen the cover. Is this where the fault codes are listed? Is the engine check light related to this?
Computer codes Where can these be read and diagnosed or read by a layman owner? Would I need help from an auto shop like AutoZone, or similar?
Thank you.

 

The OBD port is on the driver side. It is located above and to the right of the accelerator pedal under the dash. You'll need an OBD scan tool to read the codes. You may be able to take your car to an auto parts store and borrow theirs. I suggest that you buy one. The one that I have (BlueDriver) provides the basic information and I have been happy with it. Mind you, there may be better options out there for the same price. You can certainly spend a great deal more on one. The box under the glove box, I believe, is the ECM. On a side note why do you think there is something wrong with the ECM?

$100 BlueDriver Bluetooth Pro OBDII Scan Tool for iPhone & Android

https://www.amazon.com/BlueDriver-B...7-93deae8f9840&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY

 

Thank you! What does ECM for? Has it got something to do with the AC evaporator?

 

ECM=Engine Control Module

 

Any way to post a picture of what you are referencing in an attempt to narrow down what you are working with.