Chrysler Repair: 2001 Dodge Grand Caravan Injector PCM problems, grand caravan sport, dodge grand caravan

Question
Hi Roland. I would appreciate any help you can give on the following. My friend just recently bought a 2001 Dodge Grand Caravan Sport 3.3, w/flex. The van was running great for the first week and then the CEL came on and the engine started having loss of power and the engine shakes. He took it to a local garage he knows and it was reading MIL Code 27** generic scan and tool code P0204 for the #4 injector. The garage seen that the wiring harness from the injectors to the PCM had some bare spots and the PCM had a sticker saying it had been reprogrammed. A used PCM from the same exact year, make, model and a good wiring harness were put in. The garage told him this new used PCM did not need reprogrammed. The van is running, but still miss firing and still has the injector #4 code. The garage says the injector and wiring harness were tested and are good. Do PCM's in this year need reprogrammed when a used one is installed? Any other ideas on things we can check?

Answer
Hi Jenn,
The question of reprogramming depends possibly on the date of manuafacture as to whether or not it is up to date program-wise. I doubt that would explain the continuing problem with injector #4. Given that it is so persistent my inclination would be to go to a more skilled garage (if you don't have a meter and experience) and let them try to find out why this code recurs. It is not a complex technology but just requires persistence to find whether the issue is with the injector itself, or the wiring from the injector to the PCM. Because the code is the same with either pcm/harness, I would wonder about the injector itself being the issue.
Perhaps asking the current garage to replace the #4 injector would be appropriate because the alternatives seem to be exhausted by that full replacement (assuming that the wires all the way from the pcm to the injector were replaced and the wire from the autoshutdown relay to the injector was replaced or at least postively shown to be reliable). It is basically a 2-wire connection situation so it isn't rocket science. If the garage has been paid for labor that has not been effective, then perhaps they will agree to put in the injector at no cost other than the part.
Roland