Originally Posted by LEXTEK1

It is unlikely you would have the same communication issue with the three of them,yes. However, you stated you were using the MODIS platform from Snap-On. I have had the same issue with it and on some I needed to plug the 12v cig lighter adapter into the side of the TOY-1 adapter you are using. Sometimes that wont even work. You can jump terminals on the DLC1 or the DLC2 and use a voltmeter on all of the problems you are likely to encounter. This car is OBD1 and you will not get the data you may be expecting like on an OBD2 car. In my original post I outlined how to check the O2 sensors and you should do that! Its possible the O2 reading portion of your ECU was bad but, I have not seen one fail like that. The capacitors fail on the ECU and leak a brown acidic type of fluid onto the circuit board and this fluid is also conductive. Usually the failure is on the ECT Temp sensor leg or the TPS leg. Sometimes the fluid will bridge the injector drivers and cause an injector to dump fuel all the time. Code 25 will take a bit of time to come back but if it does, check the O2's. Or, you could just check them now!