Flashing and dinging CEL with no DTC's - 2007 JKU Sahara
 

I'll preface this stating that my jk is pretty much OEM, unmolested, never offroad, and has about 77k miles. Its my DD.

So I have had the classic gas cap CEL issues for the past couple months now. Tried all the fixes, new cap, battery disco, fuel system cleaners, even has been to the dealer 3 times with no dice. Fast Forward to this morning; I'm pulling out of my driveway to head to work, CEL comes on as normal, no biggie...but then it starts dinging and flashing erratically and running with noticeable power loss and stuttering/hesitation after about 1-2 miles of driving. Being the tech savvy JK owner that I am :cool:, I pull over when its safe, check for DTC's, only caught a glimpse of one before it went away and said "-d0ne-" and I am pretty sure it was a P0406. I would know for sure but the code has since gone away. I checked immediately after and it was gone also just checked on my break from work, same thing. Hesitation, dinging and flashing, but still no DTC's - checked 5 times.

I'm leaning towards it being the EGR, but I some older articles are claiming o2's or cat's?

All not exactly cheap/easy to fix and I need this thing running correctly for work next week so any info, ideas, whatever is GREATLY appreciated!!

Thanks in advance guys!

TL;DR - CEL is going crazy, jeeps running in limp mode. Advice needed.

The GASCAP indicator is probably your EVAP system. Check your vapor canister, the hoses, and connector. Even if the case is cracked and there's a minor leak can set off the CEL or GASCAP display.

P0406 is the Egr Position Sensor Circuit High but just in case maybe it was P0456 - Evap Purge System Small Leak which would make sense with your GASCAP error.

But generally the evap system wouldn't interfere with the drivability or go into limp mode. It's a conundrum :thinking:

Yea, i found it very wacky. The GASCAP notification is gone and has been gone, but the CEL is still there and comes back even after its cleared and the cap was replaced. Usually takes about 500mi's for its return.

Im going to guess the only way to be 100% certain on my issues is to take it to a dealer to see what the exact codes are?

Really dont want to spend that $100 diag fee...

...Will a code reader from Auto Zone or similar do the trick?

Usually, a flashing CEL means there is an active hard misfire. Sometimes the code stays when the engine is turned off, sometimes it doesn't. These can be very difficult to track down without a code.

I've been chasing a hard misfire on a 2003 Ranger for 2 years. Same sort of story, CEL flashes, engine runs bad, turn off, check codes, nothing. I'm about ready to set this truck on fire...good thing it's not a DD anymore.

Good luck. If you ever do get a code related to the anything, it will make it TONS easier to chase down.

I took it to the parts store, attempted to check the codes with two different Actron scanners. Both said they could not communicate with the computer. That really freaked me out. So I then gave in to my last resort, the dealer. I really didn't want to bring it there but at this point I was stuck. I'm not a huge fan of this place to begin with but their hours are 24/7 and I need to drive this thing everyday to live my life. They checked it immediately and told me that it needed a tune up. Plugs, wires, air filter, pcv. All of which I could do myself but at this point I figured what the hell. Ill give em another chance. They quoted me $430 total for the work. 115/hr labor. They also mentioned there was a small evap leak that they would look into afterwards. The funny thing is, that's the same reason why I had brought the jeep to them originally, and the next two times as well. All with them stating they couldn't find anything wrong. We shall see what happens... I will be extremely upset with if they try to pull that nonsense line again.

Also, I have a power train warranty that expires at 80k, as I said before I have 77k on the ticker now. Would a small evap leak be covered under this warranty?

What do you guys think? Any advice?