Strange issue - ETC,TracCntrl,Ck Eng lights on. Jeep runs fine..almost!

F

fstop27

New member
So here’s the deal, as short as I can. One day, Jeep runs perfect. Next morning, start it up and my dash looks like Christmas. The ETC, Traction Control, Check Engine and TPMS lights, all on. TPMS, easy fix. FYI - this is 2012 Jeep Wrangler JKU AUTO, w/ 84,000 miles, 2 1/2 lift, on 35x12.5x20 Maxxis Bighorn mud tires. (Quick shout out to Maxxis. I literally have put ALL 84,000 miles on these tires, and they still have enough tread left to pass inspection! WTH!!). Back to the issue. In my research, I’ve heard horror stories of other Jeep’s with this issue having to limp home, Jeeps just stalling out, running bad, etc. And then, hearing about multiple trips and LOTS of dollars thrown at it, and still not fix the issue. But here’s the thing. The Jeep, basically runs perfect. No hesitation, no spitting and sputtering, no stalls. Will easily maintain 30mph, or 75mph on the highway for as far as 100 miles so far. The ONLY issues I have found to date are, (1) one - it will not go into Cruise Control, (2) two - it will not shift to 5th on its own. So if I’m going down the highway in 4th, I can manually downshift and then manually upshift to 5th, and that works. (3) three - when trying to accelerate to pass, it will not kick down a gear for more rpms to pass someone. Again, I can do it manually, but not on its own like it should. Otherwise, shifts up and down like it should on auto, and no other noticeable concerns. Even MPG is the same. Like I said, I cannot afford to throw money at it, hoping something works. FYI -New oil change, new gas, injector cleaner, etc, as preemptive strikes. Also it does show - P520, P300 codes. I do know the P300 is a misfire code. However common sense would say if it were a misfire, it wouldn’t be running smoothly. Does anyone out there have any thoughts, ideas, heard of this, “like” this, solutions, etc. ??? I would really appreciate some advice and/or direction. Thanks.

P.s. Someone suggested a battery issue. All cables and post tight and clean. 1 year old Optima battery. Already tried computer reset with no luck.
 
Do you have a scanner that will read ABS/TCS codes? The less expensive ones will not.

I’ll bet you’re having a problem with one or more of your wheel speed sensors. I had basically every issue you describe (aside from not getting 5th gear, since my 2010 only has four speeds). Pulled a bunch of wheel speed sensor related codes. Dealer diagnosed worn unit bearings, which can throw speed sensor codes. I installed new unit bearings and all the lights disappeared.


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☝️Fiend nailed it☝️

At 84,000 miles, unit bearings are suspect, and rear wheel speed sensors fail for no real reason at all sometimes.

When one sensor acts up, you get the Christmas tree you describe. When two act up simultaneously, then you get full on limp mode, second gear only, no shifting.

The P300 misfire, I have had randomly on and off for two years.
 
I recently had the same issue. I used a bluetooth OBD scanner and software that can read the ABS codes (expensive) and it pointed to the left rear wheel speed sensor. $20 later and problem solved. Didn't even need to pull the tire to change it.
 
Thanks guys. I’ll look into those. While I appreciate Jeep for the “codes”, it’s not real helpful when there’s 47 possibilities, and the main one (P300 misfire) you KNOW is not it, because the Jeep wouldn’t run smoothly with a misfire. Anything else comes to mind, I’d appreciate any ideas. Thanks again. FYI - Didn’t know if you saw the comment about my tires. Just to be clear, I am in no way affiliated with Maxxis. I’m just shocked that these tires, especially being mud tires, have gone 84,000+ miles, and still will pass inspection. Personally never heard of ANY mud tire going that long. Hell, most passenger tires don’t go that long. Right?



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