Potential 2012 Pentastar issue? - Page 33 - JeepForum.com
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post #481 of 650 Old 08-06-2012, 07:39 PM
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Yup, ticking came back after a few weeks. I'm assuming that when they pulled a head off the shelf it was probably one of the bad heads. I told them to make sure that it is one of the new redesigned heads. So we shall see how it turns out.

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post #482 of 650 Old 08-07-2012, 10:54 AM
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Got mine back after first CEL P0302.
They said that code is basically a bogus code that could be anything, but did find another code B2204 which was a bad ECM. They replaced the ECM and so far so good I guess.
On the down side, this reset everthing so now my ECM is not calibrated for the 35" tires (odometer now incorrect). Not a huge deal, but I wont have my ProCal for a couple days.

As of today I would say the service at Carson Dodge Chrysler Jeep was good. I asked to speak with the mechanic so he could explain to me why a #2 cylinder misfire was a bogus code. The bad ECM can through any and all codes the worse it gets. Anyway, so far no CEL and seems to run fine. I say the service was good because the service mgr seemed as helpful as he could be.
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post #483 of 650 Old 08-07-2012, 11:01 AM
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Take it back and have them flash it for your tire size, they swapped it, they need to make it right.
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post #484 of 650 Old 08-07-2012, 11:09 AM
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Most dealers wont flash for anything outside of stock parameters.

Does anyone have any info on what exactly is changed in the head? Diagrams, side by sides, anything?
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post #485 of 650 Old 08-07-2012, 04:16 PM
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Originally Posted by medijeep View Post
He seemed surprised, and said he hadnt heard of any despite this dealer selling a ton of wranglers.
This is what's known as quid pro quo - you give me a job with a regular paycheck and I'll lie for you ad infinitum.
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post #486 of 650 Old 08-08-2012, 04:35 PM
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Another CEL today. Took it back. We'll see. Current mileage 10800. seems to be running fine.
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post #487 of 650 Old 08-13-2012, 06:55 AM Thread Starter
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Update see below link.


2012 JKU Rubi,Auto, 4.10's "takes a licking and keeps on ticking"
99 Sahara D30/44 w ARB's and 4.10's, Warn 9.5TI,AA SYE & Wood's shaft,Raingler nets,Jeeperman trail skids,Warn gas tank and steering box skid's, BDS 2" springs, Currie control arms,32" MTR's,AEV Bridger wheels, custom made tire carrier bumper,Dynomax cat back JKS quicker disco's.PSC Trail Cage,Banks header,LiteDots.PSC Trail Corners.
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post #488 of 650 Old 08-13-2012, 07:00 AM
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Thanks for that link.
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post #489 of 650 Old 08-13-2012, 07:33 AM
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To fix the problem, which Chrysler executives declined to describe fully, the company designed a "more robust" head, which it started manufacturing about six weeks ago.
So it sounds like all 2012's can have the issue since the fix was just put in six weeks ago. When did the 2013s start being produced?

Current: 2016 Ram 1500 Sport - Past: 05 Wrangler LJ, 90 and 92 Trackers and 98 Wrangler SE
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post #490 of 650 Old 08-13-2012, 11:01 PM
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Well after the second trip for CEL the dealer in Carson City told me the new ECM they just installed needed to be updated. So once again I pick it up and drive for about 200 miles. Then, about 1/4 mile into the Rubicon trail the CEL comes back on. Great. The Jeep seemed to run fine through the whole weekend. I had a blast! What a great trail! So I plan on taking the Jeep back to Carson City Jeep on Monday. On our way home Sunday night the CEL goes off. Good I guess. But then on Monday morning I get a "gascap" message on the dash. So I go and check out the gas cap. It seems to be fitting fine, but the msg stays on. So back to the dealer tomorrow. But I think I'll get the code scanned before I go just for my records.
For those keeping score, this is trip #3 to the dealer.
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post #491 of 650 Old 08-15-2012, 11:29 AM
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got the Jeep back. Had two codes. Again the P0302 (#2 cyl. misfire) which they said was bad coil and spark plug which they replaced.
The other code was a P456 which was a vapor leak combined with a "gascap" msg on the dash. Apparently my evap canister was injured on the Rubicon trail this past weekend. The factory tin skid plate was reduced to about half its normal position. Their estimate was $382 since its not covered under warranty. I'll get that taken care of when I get home. Its likely the CEL will come back with the P456 code until this is taken care of.

Some part of me thinks this should be covered by warranty. The skid plate failed, which crushed the charcoal cannister. Understandably everything has its limits, but it is a Rubicon model and it didnt withstand the Rubicon trail

add: just to pass on this bit of info, the remote start will not function when there is a CEL.
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post #492 of 650 Old 08-16-2012, 09:35 AM
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Update, for anyone that cares.

Jeep going in next Monday. Dealer already has new head (arrived a few weeks ago I believe), which they told assured me is the "redesigned" head. Hopefully, this will be it.

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post #493 of 650 Old 08-16-2012, 07:03 PM
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July Build

My 2012 JK Altitude is a July build. Do you guys think that it has the old or the new head?


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post #494 of 650 Old 08-17-2012, 06:22 PM
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Interesting read on the ticking head issue,


There have been several people that have contacted us with the concern about the relatively recent discovery of the 3.6L Pentastar cylinder 2 misfire problem.

Apparently, after some research and discussions with internal engineers and ASE certified techs, it has been found that the #2 cylinder causes a misfire due to a machining irregularly in the valve guide area. The valve in the guide is loose. It is surmised that the tapered endmill used for the head in #2 cylinder valve guide internal or external was the wrong size.

As is known with robots, if the robot has a problem and it is repeatable, it will repeat the failure for the given time period. Be it 1 shift, 1 day, or one week, these problems will then end up in the field. Only early 3.6L Pentastar V6 engines seem to be affected.

Allpar reported on this as well, but didn't give the details for this issue.


If your 3.6L comes up with a misfire in cylinder 2 over and over, you probably have the issue. The new cylinder heads are going to be available soon. For now, the very few people that have the issue will be taken care of as the parts come available.

So far, my 2011 Grand Caravan R/T and my wife's 2011 Avenger Lux don't see to be exhibiting the issue in cylinder #2. Both engines were made on or after 5/2011.


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post #495 of 650 Old 08-19-2012, 11:22 AM
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Late update

Well I reckon I should give an update. My wrangler had a CEL. dealer said it needed a new head. They ordered the head and I continued to drive the jeep. Head came about a week later.it took them a couple days to repair..(they paid for rental car)

That was a couple months ago. The jeep is much quiter on the left side. Seems smoother and runs great. I tried to have the dealer listen to the "louder" left bank when the jeep was in for oil changes...but the SA said his hands were "tied" unless it gave a code. I figured it would eventually. I am glad for 100,000 warranty. I do believe Mopar could have been a bit pro active with this issue. Looks to me they should know which engines the bad heads were bolted to...call them in and fix before there's a problem.

I am happy with my jeep. Only thing that would cause me to trade would be a diesel. I figure I shouldn't hold my breath on that.

2012 Sport..auto 3.73 limited slip.Poison Spider Rocker Knockers, Daniel Stern lighting..AEV Pintlers GoodYear Duratracs 285-70-17 springs from Unlimited Rubicon. Weathertech Mats..AEV hood, kicker speakers, remote start added.
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