Yes, there are interface circuits and software available!
94-95 3.8 use the old OBDI ALDL 8192 baud communication protocol as earlier models, but use the OBDII 4-digit faulty codes. It is not possible any more with 94-95 model to flash the codes.
You have to make an interface to get them! The data stream is in the M-pin, and there is ground in A-pin.
You can find circuits to build an interface and the best available software here:
http://www.pontiac-interface.de/
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I have used the schedule from Meyer, but I guess all of them will work.