Recent Topics
99 honda accord
by FT92. 10/16/18 02:26 AM
On The TD42 Safari.
by Silk. 10/16/18 02:23 AM
High Fuel Dilution
by Spetz. 10/15/18 11:52 PM
Northern Lights 6K Genset Rot T4 200Hrs OCI
by nicklx. 10/15/18 11:00 PM
2015 VW JETTA 1.8T TOP OF PISTON PHOTO
by Kjmack. 10/15/18 09:48 PM
Suggestions for 2009 Toyota Highlander
by suedebskillz. 10/15/18 09:38 PM
Updates to my 2002 3/4 Ton Chevy
by ls1mike. 10/15/18 08:43 PM
2019 VW Passat Reveal China
by gregk24. 10/15/18 08:16 PM
Subaru supercool is there an alternative
by urdrwho. 10/15/18 08:10 PM
Generic Toner
by willbur. 10/15/18 07:50 PM
1994 Jaguar XJS Tuneup Questions.
by Serolim. 10/15/18 07:49 PM
Pickup Truck Door Freezing Shut
by CCI. 10/15/18 07:01 PM
Help with window well drainage
by Klutch9. 10/15/18 06:31 PM
Nissan Murano Owners
by RazorsEdge. 10/15/18 06:27 PM
Dealing with my younger sister
by skyactiv. 10/15/18 05:58 PM
Jeep TJ Running Rough Before & After Repairs
by Auae85. 10/15/18 05:54 PM
RIP Paul Allen
by PimTac. 10/15/18 05:34 PM
Matches and gasoline
by jhellwig. 10/15/18 05:14 PM
PARTS MASTER #61334 CUT OPEN
by 53' Stude. 10/15/18 04:38 PM
CHAMP PH 2867 CUT OPEN
by 53' Stude. 10/15/18 04:32 PM
Newest Members
hidesertcouncil, suedebskillz, TheDirtyScreech, briantn, AL5M
66219 Registered Users
Who's Online Now
22 registered members (53' Stude, DBMaster, dlundblad, FordBroncoVWJeta, Gasbuggy, 2 invisible), 864 guests, and 36 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics292,024
Posts4,872,726
Members66,219
Most Online2,440
Oct 15th, 2018
Donate to BITOG
Previous Thread
Next Thread
Print Thread
Hop To
2004 Jeep Loberty 3.7L PO302 Code #4755900
05/13/18 12:36 PM
05/13/18 12:36 PM
Joined: Oct 2005
Posts: 306
TN
tnt31 Offline OP
tnt31  Offline OP
Joined: Oct 2005
Posts: 306
TN
Check engine light just activated Saturday on a 2004 Jeep Liberty 3.7L we bought a couple of months ago. Jeep has 205K miles on it. It appears to be running ok but my wife does indicate a little while prior to the light coming on it did seem to stumble a little bit at idle.

When I first tried scanning it with my Actron CP9410 Pocket Scan Plus code reader I got a link error. Tried again, same result. I then started the engine and got a connection and it shows the PO302 code. (Misfire detected cylinder 2). I then tried to erase the code and the scanner indicates it does erase it but the check engine light stays one and the code reader re-scans and shows the PO302 code. I am guessing it may have something to do with whatever is causing the link error that it does not erase but that is a pure guess. I have tried the scanner on two other vehicles this morning and I do not get the link error.I have visually checked the ODB II port and it appears to look OK.

I guess most important does anyone have experience with these Dodge 3.7Ls and the PO302 codes? Also if any idea why the link error until I actually start the engine and if that is related to why it will not clear? I have the battery disconnected now to see if it will clear the CEL. Leaving it disconnected for 3 to 4 hours.

Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4755905
05/13/18 12:45 PM
05/13/18 12:45 PM
Joined: Jul 2012
Posts: 389
Michigan
khittner Offline
khittner  Offline
Joined: Jul 2012
Posts: 389
Michigan
No experience with a Chrysler 3.7, but did you pull the #2 plug to see what kind of shape it's in? At 12 years and 205K miles, its hopefully not running its OEM plugs, but who knows?

Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: khittner] #4755919
05/13/18 12:56 PM
05/13/18 12:56 PM
Joined: Oct 2005
Posts: 306
TN
tnt31 Offline OP
tnt31  Offline OP
Joined: Oct 2005
Posts: 306
TN
Originally Posted By: khittner
No experience with a Chrysler 3.7, but did you pull the #2 plug to see what kind of shape it's in? At 12 years and 205K miles, its hopefully not running its OEM plugs, but who knows?


I have not yet. The person who owned this previously was the original owner and gave us a folder of all maintenance records on the vehicle. Seems like there are invoices for three of four spark plug changes. I will re-check that later.

I looked at where the plugs appear to to be and not sure I have the time to tackle it. Will probably have to take to a local mechanic I use and trust. Would like to hear others experiences if they have had this code with this engine.

Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4755921
05/13/18 12:58 PM
05/13/18 12:58 PM
Joined: Jun 2003
Posts: 17,468
Deplorable in apple valley, ca
Chris142 Offline
Chris142  Offline
Joined: Jun 2003
Posts: 17,468
Deplorable in apple valley, ca
Ya plugs first. You do know that you don't need a scanner to pull codes on that jeep?


02 Wrangler durablend 10w40
87 F250 traveler 15w40
04 Tahoe super-s 10w30
Z400 castrol T 10w40
Can am maveric edge 5w40
57 case tractor 15w40
Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4755926
05/13/18 01:11 PM
05/13/18 01:11 PM
Joined: Nov 2006
Posts: 20,083
MA, Mittelfranken.de
Trav Offline
Trav  Offline
Joined: Nov 2006
Posts: 20,083
MA, Mittelfranken.de
I don't get it. Whats the point of clearing a misfire code unless its been repaired? Its a hard fault and will come back as soon as the misfire occurs again.
Plugs, coil or injector usually. Start with the plug, check and replace the coil (COP) if defective.
A noid light will tell you you have current going to the injector and at least indicate the ECM driver is okay. You can Ohm the injectors but that wont tell you much other than if was a dead short or open but that's only part of the diagnosis.


ASE L1, Master. Deutsch Meisterbrief.
Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4755957
05/13/18 01:53 PM
05/13/18 01:53 PM
Joined: May 2012
Posts: 1,401
Georgia
AVB Offline
AVB  Offline
Joined: May 2012
Posts: 1,401
Georgia
Typically PCM codes can't be cleared on Chryslers with the engine running. I don't know why you are having issues connecting with the KOEO.

Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4756067
05/13/18 04:22 PM
05/13/18 04:22 PM
Joined: Apr 2015
Posts: 68
Saint John,IN
Highboy Offline
Highboy  Offline
Joined: Apr 2015
Posts: 68
Saint John,IN
I had a 2002 Liberty and they use copper plugs from the factory. They’re to to changed at 30k miles. Mine where shot at 30k. I would change out the plugs, very easy to do.


2006 Scion tC PP/Denso
2008 Scion tC MaxLife/Fu
2008 Toyota Highlander Pennzoil Ultra/ Oem filter
2012 Hyundai Sonata Castrol Magnatec 5w30 /Oem filter
Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4756073
05/13/18 04:26 PM
05/13/18 04:26 PM
Joined: Sep 2015
Posts: 1,548
USA
mk378 Offline
mk378  Offline
Joined: Sep 2015
Posts: 1,548
USA
If one or more of the plugs is a real bear to R&R, a lot of times that one doesn't get changed even though the receipt says it did.

Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4756152
05/13/18 05:53 PM
05/13/18 05:53 PM
Joined: Apr 2017
Posts: 95
NY
Kage860 Offline
Kage860  Offline
Joined: Apr 2017
Posts: 95
NY
Yep, I have a Liberty and those copper plugs don't last long. They're actually very easy to change though. I replaced with denso long life iridium 40k ago and have not had any engine issues or codes since. You might want to swap coils with another cylinder to see if the code moves. Maybe run some injector cleaner through the fuel. Hopefully not something expensive to fix.


2007 Jeep Liberty
Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4756265
05/13/18 08:12 PM
05/13/18 08:12 PM
Joined: Oct 2005
Posts: 306
TN
tnt31 Offline OP
tnt31  Offline OP
Joined: Oct 2005
Posts: 306
TN
Thanks for the replies so far. If the code comes back I will give changing the plugs a try. If that does not fix it then with either change the COP of move the COP to a different cylinder. Rock Auto indicates the OE plug is a NGK V-Power. May try the iridium as kage860 suggest.

Vehicle has an aftermarket Pioneer radio. I have read a few comments that aftermarket radios can at times cause a link error. Still not sure why if the engine is running though it can connect.

Chris142 - I did not know that. Will have to look into it. Thanks

Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4756314
05/13/18 08:56 PM
05/13/18 08:56 PM
Joined: Apr 2017
Posts: 95
NY
Kage860 Offline
Kage860  Offline
Joined: Apr 2017
Posts: 95
NY
The ngk copper plugs are probably the best if you change them often. The ones I got are just quality long life plugs if you only want to do it once. Most people say to stick with the original plugs.


2007 Jeep Liberty
Re: 2004 Jeep Loberty 3.7L PO302 Code [Re: tnt31] #4756637
05/14/18 08:12 AM
05/14/18 08:12 AM
Joined: Jun 2011
Posts: 1,053
Texas
wag123 Offline
wag123  Offline
Joined: Jun 2011
Posts: 1,053
Texas
Heavy combustion chamber carbon deposits are a common problem on that engine and will cause a misfire. Many people claim that it is caused by the use of E10 gas, but I have doubts about that because E10 should actually burn cleaner.
That engine is also known to have problems with bad valves (and valve springs). Before you blow a bunch of money on it you should do a compression test to find out if you have a bad valve. If you find a bad valve, at 205k miles the Jeep is toast (don't throw good money at it). Reset the CEL and sell it, that is what the previous owner probably did to you.


BOB IS THE OIL GUY® Powered by UBB.threads™