Originally Posted by jwfirebird
i think obd1 scanners require separate power so if it wont communicate its possibly just incapability of the scanner, did you find a list of compatible vehicles that scanner can read
The only other OBD1 vehicle I have is a 90 Mazda MX5, and the scanner does work on that vehicle. However, the Mazda has a very basic system, and the scanner does nothing more than what could be found by using a paper clip to jump the necessary terminals needed to make the CEL flash the codes.
An external power supply is needed (power plug, or battery connection) for the Snap-on scanner to function on either of these OBD1 vehicles.
The little information that I can find about the Sunbird wiring system shows the Sunbird to be the only model that has a blk & wt wire going to the diagnostic connector from the ECM, making a total of 4 wires going to the diagnostic connector. As best as I can see, this vehicle only has 3 wires at the diagnostic connection.
I have no idea of what the wire is for because I can't locate an accurate schematic.
Any ideas, or theories on the blk & wt wire?
Thanks again to all for the help.