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Discussion Starter · #1 ·
I have seen different posts about this issue, so I figured I would explain the issue that I am having and hopefully get some advice about it. Recently when driving my car, after it rained the previous day it would pretty much shut off, with the ABS, TC, check engine light, and the red lighting bolt all illuminated, then would kick back on and drive with all of the warning lights going off, then would repeat a few more times. I took it to the dealer, and they said after scanning, it had the P0700 and U0100 codes, and said I would more than likely need a new PCM. So, before doing that, I had them change the transmission fluid and filter, flashed the PCM and changed the transmission plug adaptor. After doing so, they took the car out and could not replicate the issue. So I took the car home, and it drove fine, which it did not rain for the few days after I picked it up. Today, it was raining while I was at work, and on the way home, it started doing the same thing. Looking to see what the issue could be, maybe there is an exposed wire and when getting wet it is throwing those codes? Any help will be greatly appreciated.
 

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It does sound like a bad connection, but where?

I would start by checking all the chassis grounds you can find (don't forget the ones at the rear of each cylinder head) to be sure that they're all clean and tight. Then check the TIPM connectors, especially the main power feed. Take a good look at your alternator connections as well, and have both your battery and alternator load tested.
 

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Discussion Starter · #3 ·
Thanks for your reply CtCarl.... I will have all of those things checked out and hopefully can find the issue. Reading over the paperwork from the dealer, it states on there "PCM is losing communication scanned vehicle and found several DTC's related to concern. 3 stored DTC's U0100 lost communication with ECM/PCM set by ABS module, FCMCGW Module and TCM". It also shows they did a "wiggle" test on the PCM wiring and inspected connections and grounds, but I am not so sure if they did a really good inspection of the wiring and grounds. If by chance everything checks out ok, and it is the PCM that needs changed, do you know of a reputable place online where I could order one from? I found this place, 2006 Chrysler 300 5.7L - PCM ECM ECU Programmed Plug&Play | Flagship One (fs1inc.com) .
 

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Thanks for your reply CtCarl.... I will have all of those things checked out and hopefully can find the issue. Reading over the paperwork from the dealer, it states on there "PCM is losing communication scanned vehicle and found several DTC's related to concern. 3 stored DTC's U0100 lost communication with ECM/PCM set by ABS module, FCMCGW Module and TCM". It also shows they did a "wiggle" test on the PCM wiring and inspected connections and grounds, but I am not so sure if they did a really good inspection of the wiring and grounds. If by chance everything checks out ok, and it is the PCM that needs changed, do you know of a reputable place online where I could order one from? I found this place, 2006 Chrysler 300 5.7L - PCM ECM ECU Programmed Plug&Play | Flagship One (fs1inc.com) .
I wouldn't be in a hurry to replace the PCM. If you check everything I suggested and the problem persists, I'd look at the TCM. I have even heard of low transmission fluid level leading to this set of codes, but I'm leaning more towards a bad connection in your engine compartment because it generally happens after rain.

If it turns out that you do need a PCM, I personally would buy a junkyard unit, and buy the programming service on that big auction site at a cost of about $50.
 

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Discussion Starter · #5 ·
Thanks again.... I am definitely going to do what you suggested first. I did have the transmission fluid changed, etc... because I did see that on here on a different post that it can cause those codes. I spoke to the dealer and they want me to bring it back on Monday, I am going to try and see if I can find potential issues with the connections first, but is there a specific test that I should tell them I want them to do for the electrical if I cannot find anything?
 

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I spoke to the dealer and they want me to bring it back on Monday, I am going to try and see if I can find potential issues with the connections first, but is there a specific test that I should tell them I want them to do for the electrical if I cannot find anything?
I can't really help you with that. In my experience, dealership service techs are, by and large, parts swappers and are typically not willing to take much time troubleshooting, especially if the fix is to simply clean and/or repair an electrical connection or replace a damaged wire or pigtail. This is not the kind of problem that I would ever take a fifteen-year-old car to a dealership for.

I also doubt that they'd take well to being told whether or not to perform a specific test.
 

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Discussion Starter · #7 ·
Got it.... I am going to see what I can find out myself and hopefully can come up with a resolution for it. I agree that they mostly want to swap parts instead of taking the time to troubleshoot the issue which i told them from the get go when I first brought it in that it happened after raining, etc.... and did tell them I believe it is a connection or wiring issue. Thanks again for all of your input into this matter.
 

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Got it.... I am going to see what I can find out myself and hopefully can come up with a resolution for it. I agree that they mostly want to swap parts instead of taking the time to troubleshoot the issue which i told them from the get go when I first brought it in that it happened after raining, etc.... and did tell them I believe it is a connection or wiring issue. Thanks again for all of your input into this matter.
No problem. Good luck with it!
 

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Discussion Starter · #10 ·
UPDATE....
So I had the PCM connections and grounds cleaned, and the power cable.... That was on Monday 6-28...
Car drove fine, no issues.... even had a pretty bad rain storm on the way home from work I believe Tuesday 6-29, no issues.. On Wednesday, 6-30 again, no issues and again had some rain. Today, 7-1 car drove fine on the way to work.... on the way home today, dry outside, it started to do the same thing, cut out.... RPM's dropped, let foot off of gas then kicked right back on... It did that twice.... So I started driving using the "slap stick"... manually shifting gears and seemed drove ok, no cutting off, etc.... I am going to look and see if there are any connections that got overlooked, etc.... If not, would it be safe to assume that it is the PCM? I did contact a local junkyard, and they do have a 2006 300C there, and the PCM is pretty cheap. As far as the programming service, how does that work?
Thanks
 

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Discussion Starter · #11 ·
UPDATE again:

Was driving home from work today using the AutoStick, and it cut out a few times, take foot off of gas, and it kicked back on.
 

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Discussion Starter · #13 ·
I have not fixed the issue yet...I am going to go back thru the connections and grounds to see if any have been missed cleaning, etc..... If not and that does not work, I am leaning towards it being a PCM issue.
Is your issue sporadic also?
 

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Discussion Starter · #16 ·
Thanks CTCarl.... I think I am going to invest in the 2 things you mentioned.... and hopefully get closer to solving this issue...
Question, how do those 2 work together?
 

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Thanks CTCarl.... I think I am going to invest in the 2 things you mentioned.... and hopefully get closer to solving this issue...
Question, how do those 2 work together?
I provided links, but AlfaOBD is a program that you install on any Android phone or tablet. Then you use the Bluetooth OBD adapter to connect the Android device to your car's diagnostic port so that AlfaOBD can talk to it.

You should Google AlfaOBD and learn everything you can. There's a positively huge thread on the RAM forum that is very helpful.
 

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Discussion Starter · #18 ·
Thanks again.... I will do some research on it and will more than likely end up getting it and the Bluetooth adaptor
 

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Discussion Starter · #20 ·
Thanks.... I just want to find the issue and fix it.... not too good of a feeling driving and not knowing if it is going to cut off or what.
 
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