what could cause the OBD2 port to not work on a 98 jimmy/blazer?

[ZL1power69]

i went and looked at a 98 jimmy for sale today at a local used car lot and everything checks out except one thing; i go to plug in my scan tool to the diagnostic port to check the status and history of the computer and i get no power out of the port. what could be wrong? all of the fuses check out. with the diagnostic port not working the truck can't pass emissions and i can't check if the computer has any codes and what not. could something just have come loose under the dash or is it something with the computer it self or could someone have disabled the diagnostic port somehow?

the guy who runs the dealership said he would have it checked out eairly next week but im just tryin to get an idea of what could be wrong with the diagnostic port. if they get it fixed and the computer checks out then i will probably get the truck.

thanks in advance

[rlith]

Either the serial line is broken or the power line is broken...Gonna have to meter it all to find out which then back track it...not fun..

[ZL1power69]

Originally Posted by rlith

Either the serial line is broken or the power line is broken...Gonna have to meter it all to find out which then back track it...not fun..

the only thing i was able to do while i was there besides testing all the fuses was to stick a volt meter on each pin of the conector and i got nothin. where do those 2 lines u are talking about run or how are they routed? the guy who runs the dealer said he would have it checked out and call me back so we'll see.