Hello everyone! I am new to the forum, & have seen a few threads that have touched on this issue, but here I go.

I have a 1996 Chevrolet 1500 Centurion Conversion Crewcab truck. The check engine light has come on & gone off for the past few weeks & I have had zero luck in trying to diagnose the issue using an OBD II diagnostic tool.

I've gone to a few different places to see if it was just a bad machine, but they all will not connect to the truck & read.

• I have checked the lighter fuse & it is ok

Are there any other fuses that could be keeping this from reading correctly?


Does anyone know which wire off the back of the diagnostic port is the serial data port wire? If so I'm wondering if that wire isn't damaged & if I could jump that wire with a new wire & splice it in near the computer under the hood.


Any help will be greatly appreciated!


Thanks,

Andy

 

I would disconnect the battery for 90seconds and reconnect and see if the check engine comes back on. I could be a random fantom code . What engine is in the truck?

 

It has the 305.

 

I'm just really at a loss on why it isn't working. Any ideas on how to troubleshoot this would be awesome, thanks!

 

Like I said...Disconnect the battery and see if the computer resets. If not then look for a another problem. Get a repair manual. Hayes manuals are around $30.oo and contain a wealth of info about your trucks systems and include wiring diagrams for the factory systems. Just my 2 cents. The folks on this forum have a lifetime of knowledge. Do some basic diagnostic work and then come back with some meaningful info and you'll get the help you need.

 

does the scan tool power up? at the dlc check for power at pin 16 orange wire. it should have battery voltage. check for grd at pin 5 black/white. the uart data line is pin 9 tan. the class 2 data line to the ecm is pin 2 purple wire.