Pcodes

[DaughterKJ]

Good evening folks I am new here and looking for help on my daughters new to her Liberty Limited 07. She was on the way to school today and it died on her. I put my OBDII on it and pulled the four following codes, P0401, P0420, P0304, and P0507.

I am not to concerned with the CAT code, (420) however, I did start it and seems there is a bit of a knock/misfire. However, I figured a four code pull on a Jeep motor I am unfamiliar with I could reach out to you fine folks on your thoughts before I start throwing parts at the damn thing. She's only had it a month (new to her) so I feel pretty bad. It's been driving just fine until today.

If you could provide your thoughts I would appreciate it!

Have a great night,
YouTube and Forum Certified Dad Mechanic :winner_third_h4h:
Tom

 

[ltd02]

Could all be related. I'm not too familiar with the drive by wire systems on the 07s but these could all be related to a vacuum leak in the EGR system. I'd check all the plumbing around it and if nothing looks bad it may be a bad EGR (PO401). Could be a coincidence and may be a bad IAC too (PO507) or a bad plug/coil/injector for the PO304, but I'd check any vacuum lines around the EGR first. If a vac line is bad I'd check all others too.

I'm not a mechanic but I've broken enough things to find out how they work.

I sure others will be along to help soon.

 

[tjkj2002]

P0304 misfire code is the most damaging,plugs and/or coil could be the issue.

Sadly the '07 uses a EGR which relates to the P0401 code,could be cracked tube or stuck open EGR which then will cause the P0507 code(idle higher then expected,not a IAC code).Major pain in the rear to do on 3.7/4.7's.

The P0420 will need to be diagnosed properly as it can cause the P0304 code.Eitherway needs to be fixed.