How do you extract 1990 Volvo 760 Turbo Wagon Engine Codes?

My indestructable 1990 760 Turbo Wagon just started running like crap today, it would idle poorly then die with any load on the engine. I found a few suspect vacuum lines, especially the one to the fuel pressure regulator, and after replacing them it seems to be running better and is driveable, but not great. And now the check engine light is on. How do you read the codes ?? Is there a magic incantation that will cause the codes to blink out somewhere ?
How do you extract 1990 Volvo 760 Turbo Wagon Engine Codes?
There is but there is not enough space here to tell you how or to list all possibilities of every code. I would get it to a shop that can diagnose obd1 vehicles and have it checked out. Be sure to use a reputable repair facility that employs ase master certified technicians. Try alldatadiy dot com for specific instructions.