Chrysler Repair: 99 Plymouth Breeze 2.4 DOHC, plymouth breeze, failure rate

Question
I am a self-employed mechanic, and a customer's car is showing 2 trouble codes involving the injector circuit and the O2 sensor showing rich condition. My scanner shows all sensors reading either zeros or extreme conditions, the ECT sensor shows -64 degrees and the IAT sensor about the same. I checked a fuse for the PCM/ASD he said blew out several times and now it sparks when I replace it without blowing. Before I do a lot of troubleshooting, I have been looking for TSB's, etc. Obviously he has a short; what I was wondering is could it be a short inside the PCM itself? Is this a common Chrysler problem? Or is there a particular wiring short circuit problem common to these models? Thank you very much and have a great day, Elliott.

Answer
Hi Elliott,
I think it would be good to look more closely at the fuse that has blown and is now appearing to have an unually large draw. You said it was for the PCM/ASD. Can you perhaps tell me where is it located, the number of the fuse, the size of the fuse, and anyother associated label as to its purpose? Have you by chance measured the resistance of the cold side of the fuse to ground so as to get an idea of what that current draw-dowm might be? We can look at the various components are that are powered by that fuse, and also I can tell you the pin assignments for the wires that are attached to the fuse. I haven't heard of an unusual failure rate for the PCM, so let check the wires before throwing money at the problem.
Roland