Hey guys i have a strange problem,

Bought a 2014 jeep JKU a few months back, when i got it there was no gas in it. Stopped a few blocks away from where i bought and filled up, drive was about 2hr to get home with no issues. Since then ive been fighting a knock sensor issue ever since, I bought a bluetooth OBD2 dongle and have just been turning it off whenever it comes on. When it does come on its normally right after I get gas, ill turn it off and then be good for a few day, there seems to be no ill effect from it, i cant hear a knock, no retarding of timing, or lose of power. Up until a few weeks ago its been warm enough to drive with the windows down and not need the blower fan for cooling or heating.

The other day the light came on while headed to work, get out of work turn on the jeep no light. drive 30min across town and park, get out and look at a roofing job i had done over the weekend. Jump back in and light comes back on, 30 min drive back across town to home, turn off the jeep start it right back up and light is off.

For the past few week ive had the blower fan on nothing more then half way on and run ether the vents or windshield, anywhere from full heat to full cold. Haven't had a single knock sensor issue since leaving the fan on. I did buy a knock sensor to replace the one on the jeep but im ether missing it or im looking in the wrong place, from what i read it should have been right behind the passenger motor mount which there is something there but does not look like the part i bought. another post said its in the valley of the motor which im just not feeling right now to pull apart to replace.


few things i did try
running on 93 octane
cleaned the throttle body
replace spark plugs and coil packs NGK 9723 plugs and MSD red coil packs
exhaust was replaced from cat back
its had 2 oil changes since june when i bought it, Royal Purple HPS 5W-20 Mopar oil filter, nothing unusual in the oil and no loss

Anyone have any ideas other then just leaving the vent fan on, i mean it seems to be working for now.

 

having the same problem here. I actually just had the engine replaced due to overheating on my 2012. As soon as I got 50 miles down the road, I got the light. Reset and get it again. I did notice that knock sensor 1 is reading .14ish volts while 2 is reading .5ish. Is this normal?

 

Just a small update, Jeep has around 93k miles on it. Replaced the PCV valve over the weekend, think it was the original to the jeep, and installed a Mishimoto oil catch can, drove around for over an hour with no check engine light yet. Not sure what engineer decided it was a good idea to put the PCV valve there but they should be shot.

It was a little easier after reading most people go in from the inner fender, luckily i replaced my fenders with Metelcloack and inner fenders with Fishbone aluminum liners. Fishbones came out with a few bolts and i was kneeling on top the fenders to gain access to the the PCV valve and hose.

 

so you’re saying that you think the PCV valve fixed it? Mine sometimes takes 100+ miles to come on.

 

Right now its hard to say, it could stay off for a month or do it 3 times in a week before. Im going to drive it as much as i can and see what happens, one thing that i did notice is if i have the blower fan on at any speed just blowing air into the jeep, ether hot or cold doesnt matter, i could drive for weeks on end without the sensor going off. i might not have issues again till spring time when i just run with the windows down and the fan off.

 

interesting for sure. You’re certain you’ve seen it enough to know that having the blower engaged keeps it off?

 

I bought the jeep in June, to get it home i drove over 2 hours. It was a rainy/misty day so i had the windows up and the fan on with no issues. during the summer i would mostly drive with the freedom panels off and the windows down, anything under a few miles and i had no issues. The gas station i go to is about 4-5 miles away, I could drive there get gas and then not even 100 yards down the road the light would come on. I was turning the light off 2-3 times a week. A few months pass and i was over at my brother house late and had turned the fan on on the way home, didnt pay much attention to it but the temp knob was set at 50% and fan was just a few clicks above being turned off so didnt really notice it being on, a week passed buy and the check engine hadnt turned on. I just leave the fan turn on a 1/4 way all the time now, have seen maybe 1 a month since around September.

 

Same here. I have same experience.