cant read computer

[95z28m6]

As of this thursday I am the proud new owner of a 1995 z28 m6 camaro. I bought the car knowing that one of the sensors was messed up. (intermintent, strange idiling, missing, check engin light) this only happens every so often. most of the time the car runs great. i decided to take the car to autozone to have them scan my computer. well come to find out the scanner cant link up with the computer. At first i thought the computer might be bad but then i talked to the previous owner of the car and he said that he just replaced the computer to try and correct the problem.

My question is has any of you f-body owners had this problem with the obd2 port? Any help would greately be apreciated. This really sucks because until i get the port fixed I will have to test every sensor out seperately, and i cant even get a power programer.

[ct91rs]

You might have to take it in to a shop that has a decent scanner. The ones Autozone have are very generic. Most of the time they will read an OBD II code, but '95 was a cross-over year for GM, and they are unable to read some systems with an OBD II port. You might have an OBD II port with an OBD I system.

[corning_d3]

He's right, the 95-96 OBD I and II changeover is a pain in the.....neck. I would recommend using a GM Tech II tool, but it's only available at colleges with ASE Tech classes and dealers...

[ASE jish]

im having the same problem right now myself and the diognostic procedure is as long as a novel. I tried scanning it at work but both our snap on heritage (obdI and II) and generic obdII scanner couldnt pull codes none the less get signal. Seeing as how you replaced the computer that narrows down your possibilities pretty well. You need to check all your wiring harness's for broken or poorly insulated wires, check for poor grounds, and check for poor mated connectors. ( this includes at the obdII scan port.) Also try probing the scan port proms for voltage. i cant exactly remember wich prom off hand should have constant power but if you put the ignition in the on position and show no power at any proms, go to the power supply line to the computer and probe it for signal, if signal is present before the computer but not at the scan port you just cut the system in half. ( meaning your problem lies between computer and port.) you would then have to trace all your wiring between the two. !!!! but dont forget to start simple, check your underhood fuses and relays as well as in dash!!!!
nothing like doing hours of diognostic work to just find a blow fuse or relay. lol

[95z28m6]

well the problem was simple, It turned out to be a obd1 system with an obd2 port. Gotta love those crazy chevrolet enginers..... always keepin me on my toes!

[cuda_dude]

yup as stated above 95 was the change over year ... they kept the obd1 computer but add an obd2 port.... the easiest way to read the computer is with a laptop and an aldl cable... http://www.mastach.com/