Cyl 6 Misfire. P0306. 2015 and 2016

sandfrog · Nov 30, 2015

Hello Y'all
I have a 2016 that has had a P0306 since day one. The light comes on around 4500 rpm. It blinks and goes away. Sometimes it will blink and then go solid. The motor sounds fine during all of this. It really doesn't feel like a miss to me. I have seen a few posts out there that describe something similar. This seems like an erroneous code. So far the coil, plug and injector have been swapped with cyl 1 and the problem stayed with 6. The cam/crank relearn has been performed and the adaptive numerator has been relearned. Compression and leak down have all been checked and are well within acceptable range. Has anyone out there had this and your dealer has some info that perhaps I don't? Seems like a software issue. At least that is what I am hoping for. I really don't feel like having a new vehicle with a motor swap before 2k miles.

Any info is appreciated.

WJCO · Nov 30, 2015

sandfrog said:
Hello Y'all
I have a 2016 that has had a P0306 since day one. The light comes on around 4500 rpm. It blinks and goes away. Sometimes it will blink and then go solid. The motor sounds fine during all of this. It really doesn't feel like a miss to me. I have seen a few posts out there that describe something similar. This seems like an erroneous code. So far the coil, plug and injector have been swapped with cyl 1 and the problem stayed with 6. The cam/crank relearn has been performed and the adaptive numerator has been relearned. Compression and leak down have all been checked and are well within acceptable range. Has anyone out there had this and your dealer has some info that perhaps I don't? Seems like a software issue. At least that is what I am hoping for. I really don't feel like having a new vehicle with a motor swap before 2k miles.

Any info is appreciated.

Does the vehicle sit for long periods of time? I'm thinking maybe valves are sticking in that cylinder from varnish. I would run a fuel cleaner and decarb anyway. My next guess would be you have an intermittent short or open in your primary ignition or injector circuit, like a wire loose or rubbing on something.

sandfrog · Nov 30, 2015

Thanks WJCO. Only 4500 rpm would rule out the wire etc. On the valve sticking it is a 2016 that started this at 300 miles. I just ran on a long highway trip. 600+ miles. Valves are clean for sure.

WJCO · Nov 30, 2015

sandfrog said:
Thanks WJCO. Only 4500 rpm would rule out the wire etc. On the valve sticking it is a 2016 that started this at 300 miles. I just ran on a long highway trip. 600+ miles. Valves are clean for sure.

Strange for sure.

WJCO · Nov 30, 2015

Just found a similar thread. This one looks like the PCM was the culprit. My other thought was maybe a crank sensor.

http://wayalife.com/showthread.php?24800-2014-JKUR-P0306-code-Left-Cylinder-Head-being-replaced

sandfrog · Nov 30, 2015

I'll check the software version tomorrow. I wonder if anyone else is seeing this.

Remlap · Nov 30, 2015

sandfrog said:
I'll check the software version tomorrow. I wonder if anyone else is seeing this.

I responded in other thread too.

My 2014 was identical - they replaced head, then crankshaft, then PCM, then motor for the fix.

sandfrog · Nov 30, 2015

Thanks for the reply. Did they tell you the issue with the motor?

Remlap · Nov 30, 2015

sandfrog said:
Thanks for the reply. Did they tell you the issue with the motor?

They did not, but seemed sure it was a fix. I don't know shit about motors though so didn't really know what to ask anyway.

sandfrog · Nov 30, 2015

No worries. Thanks again for the reply. Hopefully the cause will surface soon.

crowrb29 · Nov 30, 2015

Had this same code on my 2013. It was a cylinder 6 misfire. They had to replace the head. I figured they'd have that bug worked out by now.

Bandit1 · Dec 1, 2015

Probably a reflash issue
Of the pcm
Being that new

sandfrog · Dec 1, 2015

I'm hoping so. Engineers from FCA are working on something and are supposed to release a fix. I just don't want to replace the motor. Not my idea of a mod I want. Unless they'll spring for a Hemi swap.

ADee1 · Dec 1, 2015

First time post here, thanks for allowing me to join! I just took title to a 2016 Rubicon Hard Rock. I waited hoping the head problem was history, reading this is disturbing. :grayno:

WJCO · Dec 1, 2015

ADee1 said:
First time post here, thanks for allowing me to join! I just took title to a 2016 Rubicon Hard Rock. I waited hoping the head problem was history, reading this is disturbing. :grayno:

Welcome to WAL.

ADee1 · Dec 1, 2015

WJCO said:
Welcome to WAL.

Thank you, it is nice to be here.

sandfrog · Dec 1, 2015

Hello ADee.

Mine is a Hard Rock also. I really don't think it is a head issue. No ticking and it really doesn't feel like a misfire. I could be wrong but my belief is this is something else.

JJK · Dec 2, 2015

My 2014 had the same thing happen at around 6,000 miles. Engine light came on while we were on a long road trip. No ticking, no loss of power, nothing. Dealer said drive it in. They replaced the head like it was no big deal to them. No problems after 6,000 more miles.

Now that I think about it, we had about a 30 mph head wind for most of that last leg and I was defenently pushing 4500 rpms at times.

sandfrog · Dec 2, 2015

Hello JKk. Thanks for the info. I'm not sure what to do at this point. I'm just in holding pattern now waiting on Chrysler to make a decision.

Clifford33 · Dec 2, 2015

Mine is misfiring right now too. It's showing PO132 and PO300 changed my 02 sensor but still shows 02 sensor and it's still misfiring anyone know what's wrong?

Cyl 6 Misfire. P0306. 2015 and 2016

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Caught the Bug