Reading Trouble Codes?

SIL bought a beat to sh*t, 1990 4Runner and the check engine lights keeps coming on. Is there an easy way to read the error codes so I can fix the problem and get the light off? The previous owner didn't remove the skid plate to change the oil so I thought there was a major oil leak when I first saw it, and then there is a clogged cat, and the exhaust system is missing after the rusted out muffler.

It took a whole can of intake manifold cleaner to get the throttle body to open and shut easily, not to mention the air cleaner looked like a black beehive. The receiver draw bar had to beat out with 4lb hand sledge...

Howard

 

http://www.yotatech.com/f116/check-engine-light-codes-obd1-91186/#post50374865

 

thank you...I will see if I can pull the codes today.

Howard