2014 JKUR - P0306 code - Left Cylinder Head being replaced

Saw the other thread linked to this, motor was replaced and no problems since - have about 17k miles now - 6 or 7 on new motor.

They had replaced the PCM prior to the new motor with no change in symptoms.
 
Another 2014 JKUR with P0306. This was on Day 1 of a 3k mile road trip through Yellowstone/Moab/Ouray so I was very nervous about needing a full head swap. I stopped a Billion's in Bozeman for them to diagnose the issue. They plugged in and immediately said it needed a PCM update. They reprogrammed and I have had no issues since. I have only driven it once since then though. I'll report back if I get a CEL again.

Of note, my 2014 has 40k miles on it and I received the CEL after 8 hours of driving in ~80-95 degree heat. Engines RPM was around 4200 and coolent temp was consistently ~220 through the trip. I pressed on and drove another 400miles to Bozeman. The CEL flashed a few times once I got in to the mountains in Montana. It was always around 4200rpm and as it was downshifting after I crested a hill.
 
Our local stealership has tried blaming it on oil and oil filter and larger tires too. It's happening on '13-'14's with automatics with 35 and 37" tires. One friend was told his 37" tires stretched the timing chains!
Yes, press customer care for the extended warranty, they will give it to you.
 
Just a thought

I wonder how many are using the ProCal module? I am sensing the PCM corruption?
 
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