Multiple misfire, stalling failure to communicate with ECM/PCM?

2014 DODGE TRUCK
250,000 MILES • 4WD • AUTOMATIC
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FREERIDER78
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2014 Ram T1500. Random multiple misfires, failure to communicate with ECM/PCM, coils B,C,D. Not sure of code numbers. Replaced throttle body and did relearn. Replaced pedal sensor assembly. Checked PCM grounds and fuses 10,21,22,57 ,72,77,78. Disconnected battery for 15min. Engine idles rough, shakes and knocks, and stalls. There is also a surge in the idle.
May 4, 2026 at 4:20 AM
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STRAILER
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Please upload a short video in your response of the problem, so I can see what's going on. We need the codes number so lets check the fuse number 44 in the fuse panel under the hood. This is the fuse that runs the data port, also we should do a compression test so we are not chasing a bad engine. This video will help.

https://www.youtube.com/watch?v=KOxIm1F8AW0

Please go over this guide and get back to us.

May 4, 2026 at 3:21 PM
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AL514
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Hello, if you are having issues with network communications, it would help a great deal to know the "U" codes, which are module communications codes. There must be other modules setting a No Comms with the ECM correct? Another module on the network might be effecting the ECM or a wiring issue with the canbus network. If you can write down the codes, starting with getting communications back up is where you want to start. What type of scan tools or other diagnostic tools do you have?
May 4, 2026 at 3:26 PM
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FREERIDER78
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He took the truck to a shop and the guess(diagnosis) was a dropped valve.
May 17, 2026 at 3:20 AM
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AL514
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Did they give any explaination to the U codes? and are there any still setting? U codes can sometimes set and be left in memory if battery voltage ever drops low, so if they did not clear them, write down what codes you have for the entire vehicle, erase them and see if anything comes back. If anything, we can look into it. Did they recommend an engine replacement?
May 17, 2026 at 3:39 AM
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FREERIDER78
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I haven't heard anything more. If we go any further with it I will let you know. If so I'll try the suggestions you gave but for now it's a dead issue. Thank you.
May 31, 2026 at 3:22 AM
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AL514
  • CAR REPAIR CONTRIBUTOR
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Sorry to hear that, we do hope something good will happen with it.
May 31, 2026 at 6:43 PM
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