Quote Originally Posted by BigTruckDriver
...on older computerized vehicles like my suburban you can pull the codes with out a "scanner" but dont know at what year they stop being able to do this....
'95 was the last year of "OBD I" for GM, where you could pull the codes by by using a jumper wire and counting the flashes of the MIL. For '96 and later GM switched to "OBD II" which forces you to actually connect a scanner.