Chrysler Repair: 1996 Voyager minivan:ecm replacement needed?, plymouth dealer, engine computer

Question
Two problems:
We were advised by the Plymouth Dealer that the engine computer control module needs to be replaced.  Symptoms are sluggish, check engine light is on, acts like it runs on less cylinders, rich exhaust fumes, idles rough.  How do we change that out and how do we calibrate the new computer?

Also, some time ago we replaced the climate control A/C switch panel which was used but tested to be good.  Ours was bad.  We calibrated it and it still doesn't function as it should (although we do have A/C now).  There is a clicking on the passenger side front under dash when the A/C is first turned on and then it quits.  Any ideas on where to turn next?  We recently replaced the relay that corrodes on the firewall (allows the A/C to work???).

Answer
Hi Kathi,
The '96 model year was in the interim between the two fault code systems, I and II. So you have two ways to find out if what the dealer said is true. Did the dealer tell you what the fault code numbers are? If so, let me know what they are. If not, call back and ask, or better yet get another readout, for free ideally, at an Autozone parts store. The old fault code system let you get a limited amount of codes by using the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light,which remains "on",  to begin to flash,
pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to be sure you get a consistent answer.
Let me know either or both code answers.
Can you be more specific about which relay you replaced on the firewall? and also where the clicking is coming from that sounds like it is under the dash? Try turning on the AC while you are parked so that you can investigate that further.
Roland
PS Use the "thank/rate" tab to get back to me with the answers, without having to wair for me to be 'available' to take a question.
Also tell me which engine you have.

Ok, we got the check engine light "code". This is what it does after doing the on-off-on-off-stay on: it flashes this many times and we did it twice and they match: 1,2,4,3,5,5 The clicking sounds like it is behind and below the glovebox. The replacement part was a plug in that goes on the firewall (top) on passenger side... simple part but can't remember what they called it. It is a 3.3l engine.


Hi Kathi,
Thanks for that info. The only relevant code is 43. The 12 says the battery connection to the computer (or the battery itself?) was disconnected in the past 50-100 key cycles. If that is not the case, then I would check the battery cable clamps/interfaces with the battery posts. It is possible that there is a poor electrical connection to the computer but it isn't likely. The 55 says "end of code readout"
The 43 says that there is a problem with the spark generating system, specifically that it isn't drawing enough current to make a good spark. It might be the system as whole, or just affect one of the three circuits to the spark coil individual sections. A readout via a code reader plugged in under the dash at a socket near the steering column would differentiate between those two possibilities so try to get that before jumping in. It could be the wiring from the computer to the spark coil pack, or one of the 3 primary coil windings is defective, or possible the ASD relay may have a bad connection to the coil pack. The ecm could be the cause, but again the second code readout would tell us if that is true or not.
There are no relays under the glove box in the cabin that could make a clicking sound. I suspect it is something in the engine compartment on the other side of the firewall in that area, such as the ac compressor clutch relay or refrigerant pressure switch. So listen after opening the hood for the sound over on the passenger side when you can hear it from the cabin side. It could be that you are low on refrigerant.
Thanks for the kind evaluation and nomination.
Roland
PS The part that was replaced on the right side in the engine compartment was most likely the blower motor resistor block which is a part that is prone to fail.