Wiring diagrams for 96/OBD2

[Huskymaniac]

Originally Posted by TomsSVX

Closed area network was mandatory for all obdii vehicles. This way all modules associated with powertrain can talk to eachother... take one out and the engine ecu will cry about it

Tom

Are yousure that was true back to 1996? See this link:
http://www.evoscan.com/technical-veh...rea-networking

I have uncovered one difference in the wiring. I had to look at the wiring of a 1997 legacy tcu to find it. The tcu pin that used to run to the power mode light for obd1 models runs to the atf temp light on obd2 models and the pin that used to run to the atf temp light now runs to pin 80 on the obd2 ecu. The tcu sends some sort of diagnostic signal on that line to the ecu but I have no clue what. Could it just be the blinks that used to be sent to the atf temp light on obd1 models? Maybe there is a way to drive that pin on the ecu to make it happy.

As far as I can tell, those are the only lines that may prevent an obd1 tcu from plugging into an obd2 car. Obd2 tcus also monitor the supply voltage on the tps but the obd1 tcu does not and that pin on the obd1 tcus is a NC so it shouldn't matter.