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Limp mode on a manual

20578 Views 60 Replies 11 Participants Last post by  WillysGal
I was driving on an easy trail earlier today, but hit a bump or rut with some force. The jeep made a jeep, the ESC Malfunction and MIL Lights illuminated, and limp mode was enabled, or what I believe to be limp mode: power drops off in all gears at 3k.

I am going to the dealer tomorrow; just happened to have an appointment.

Any thoughts on what is going on.

My limited searching resulted in auto transmission limps.

I doubt there is any causal relationship, but:

1) Earlier today I pulled out a stuck F150. Low 1st easy pull, no jerking or other "violence."

2) Saturday I got stuck in sand down to the frame, and needed to be pulled out with a winch.
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Sorry, I don't have any answers but I'm interested in what the responses will be. Also, if it's not much trouble, will you report back what the dealer says?
Shall do.

Closest I've had to that is just the ESC light coming on. I had forgotten to turn off traction control (I always do that when off road) that one time. A little while after I turned it off and continued the trail our group was on, the ESC light went away after I assume the Jeep decided things were ok now. It had never done that before or since so I assume I just freaked out the traction control system and it decided to throw a fit for a while. I didn't have the MIL come on though so that's weird. Interested as well to know what the problem is in the end.
Shall do.

You damaged a wheel sensor.
This makes sense as I also heard an unusual noise from my front left wheel.

I read R1's post, but am interested in your opinion: would this problem cause the power drop too?

I think limp mode is only for automatics. If your power is dropping off at 3k my guess is something else happened.

A wheel sensor, as the previous poster mentioned, would cause your MIL and ESC lights to come on but shouldn't cause the engine computer to reduce power. Did you possibly dent a muffler or exhaust pipe, causing a restriction that reduces power at higher engine speeds? Best theory I can come up with...

Keep us posted.
Muffler and exhaust look okay.

The power drop off is not a sputter, it is just that: power stops building. I think it is programmed as it does not stall.

Otherwise, shall do.
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Did you try the key dancing thing to look at what code the MIL threw?
Tried the sequence twice; nada.
Update: Dealer diagnosed the problem as a bad cam position sensor. The dealer further explained that the ESC and 3K cut-off were a result of a limp-mode caused by the bad cam position sensor.

A new cam position sensor was installed under warranty.

Wheel sensors checked out ok.

I will post further updates if the problem is not resolved.
Earlier today driving on an easy peasy dirt road, and hit a minor - really nothing - bump, and bam: CEL and ESC lights come on, and no power over 3k, again ... :(

Cannot get to the dealer for another week ... :(

Do u not have a code reader? It could be a million different things.

Have u tried resetting the ECU yet to see if that fixes the issue?

Unplug the negative terminal, turn on your headlights (to bleed the residual power.) leave it sit like that for about 15min while the power bleeds out, then reconnect the terminal.

This sounds like a computer problem to me.
Thanks. I'll try that and report back.

Also, forgot to post the code. It is: P0369
P036x are cam sensors sir.

I think 0369 is sensor 2. I'm betting it's a loose ground. Check the grounds on all the cam sensors.

Which one specifically was it last time?
My paper work indicates replacement of the right side cam position sensor.

How do I check ground on the sensor?
Do u not have a code reader? It could be a million different things.

Have u tried resetting the ECU yet to see if that fixes the issue?

Unplug the negative terminal, turn on your headlights (to bleed the residual power.) leave it sit like that for about 15min while the power bleeds out, then reconnect the terminal and see if the problem goes away.

If it does, just drive it normally for a while to see if it does it again.

This sounds electrical/computer to me. My guess is you are jarring something loose. Make sure the terminals are tight while your under the hood.

Either that or there is a loose ground somewhere feeding the ecu.
Did the steps above.

The results:

CEL and ESC lights did not light up, and the Jeep drove normally.

I drove over some local speed bumps at greater speed than the bump I encountered earlier today in an attempt to recreate the problem. Jeep drove normal, despite multiple attempts.

I have a dealership appointment next week, and still plan to bring it in. Not sure if the rest is the fix or not. Something is obviously causing the problem, and with my luck it will happen again on a remote trail, and it will not reset.
Ok so the right side is cam 2 I believe.

Follow the radiator hose (main hose) to the engine block. Right below it will be the #2 CPS. The sensor will be plugged into a Molex harness. (See image.) make sure the harness is fully seated and follow the wire loom until you see where the ground wire terminates. It's possible it terminates into a common ground, in which it's hard to tell exactly WHERE it could be loose. Your best bet is to tighten all the grounds you can see and ensure they are seated.

This is most def a loose connection somewhere. If the sensor was indeed faulty, then resetting the ecu would initially clear the problem, but as soon as the computer realized the sensor was bad, it would have immediately happened again. Probably minutes after you started driving.

My bet is that something is loose and by jarring the vehicle enough, it shorts and causes the problem.

It is probably:
A: loose battery terminals.
B: loose ground
C: something wrong with the CPS harness plug.

I find it highly improbable that two brand new sensors would be faulty.

It has to be electrical.

I would document as many details as you can with this particular incident in a notebook somewhere so you can tell the dealer exactly what happened and how you cleared it. Hopefully they will figure on it being electrical as well and know exactly how to rectify it. I say write it down, simply because if it was me, I would completely forget in a week.

I'm willing to bet it was one of the batt terminals that were loose. If you tightened the guts out of them after you reset the ecu, you may not have the issue ever agin.
First, thank you so much for taking the time and effort to write this up.

I will do as you suggest - particularly the tightening of the battery terminals - and report back.
No problem sir!
A loose batt terminal can cause ALL sorts of bizzare problems in any vehicle. I'm willing to bet that is the issue, as typically the simplest solution is usually the right one. But there very well could be a faulty plug, a loose ground, or a million other manufacturing defects that could have happened during assembly.

I would def, still have it given the once over by a service shop and tell them the details of the problem, how you resolved it, and why you feel it is electrical in nature. Then hopefully someone more familiar with the wiring of the engine can ensure that everything is buttoned up properly, since it is under warranty.

Good luck. Let us know how it turns out.
This morning, I went and double checked the battery terminals. I opted not to dig into the grounds as frankly I was intimidated by the degree of work necessary to reach that part of the engine.

Went for a drive on the same offending road as yesterday. After about 4 miles of washboard, the CEL and ESC lights came on again. Engine rpm drop again at 3k.


The "key dance" does not display any code. Tried a couple of sequences.

I suppose on the bright side I eliminated the battery terminals as a causal factor. I did check that they were still tight.

I have not reset the computer, and am not sure if I should. If I do, will I lose the history of the CEL events?

I have a service appointment scheduled for 7/18/14.
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Hope this all works out for you, I know how frustrating these issues can be. And as always keep us posted.
Thank you for the kind words.

Certainly shall do on updates.
Yeah don't clear it this time. Hopefully they will delve further than simply replacing a cam sensor that is probably fine.
Got it.

Thank you again for all your help!
Some weirdness:

So, I start up the jeep this morning. CEL light on, but ESC is off. The jeep exhibited this during the first occurrence. On engine start, only CEL displays, and the ESC will illuminate at some point later, seemingly after a jar or bump in the road.

Anyhow, drive to the gym, and about an hour later, I start the jeep again, and no CEL display.

This has not happened before. That is, once active the CEL stayed illuminated at all times.

1. All error lamps have been off since my last post above.

2. I went to the dealer today, and they could not find any problems at all. They read the codes, but tell me that components checked out ok. They also told me that they checked grounds and the wheel position sensor.

3. I had a long, but not confrontational, discussion with my service advisor. He seems sympathetic to the problem, and I prefer not to poison my relationship with him. Anyhow, next step is to see if the error lamps display again, and then leave the jeep for an extended period.

4. Driving home, I (of course) drove down the gravel road (referenced above), and of course, no error lamps.

I am thinking that my next action will be to take a local easy trail this weekend, and see if that will trigger the problem.

3.5 miles down an easy trail and I am back to square one ... :(

No code was displayed when I did the key dance.

I will try to get in to the dealer tomorrow or Tuesday.
Sorry you are having such issues. This would drive me crazy.

I'm still convinced of a loose connection.
Thanks; and, yes, this is making me a bit bonkers.

BTW, this afternoon, all error lamps are off again.

The intermittent nature of this problem concerns me. Will the dealer simply do another cursory check, and say it's okay. Doubt that the dealer will actually bother to take it on a dirt road, and then if they do, the problem may not occur. I suppose lemon-law criteria is my leverage to convince the dealer not shrug this off. But, this is becoming a PITA.
See if one of the service guys will go with u to recreate the problem?
That may work. Good idea. Thanks!

Jeez, that is so strange. Are you taking pictures when the CEL is on? If not, start so you at least have some evidence if you end up wanting to pursue a lemon case. It does seem like something must be loose. Sorry you're still dealing with this!
My wife suggested the same. Great minds ... :)

Great idea! Maybe even setup a video camera to record the dash while you're driving over the area where you experience it.
Another good idea. Good project for my 11 yo. Thanks!
Jeep is at the dealer.

Dealer confirmed that they can read codes that seem to "self clear".

Dealer provided me with a loaner, which they did not have to do. So, I have to commend that.
Hope they figure it out and it's an easy fix!
Much appreciated!


Just got a call from my dealer, and they replaced the cam position sensor again.

The service advisor agreed with my skepticism that two cam position sensors from two different sources (factory and dealer) would both be bad, so they will keep the jeep for a more thorough test on rutted washboard type road, assuming they can find one close by ... which, this being Phoenix should not be too hard, I hope.
Dude, sounds like they are treating you right!
Absolutely agree. The service department has been good; no complaints from me.

But, I fear my relationship with the dealer is about to be tested (see below :( ).

That would be quite a fluke unless something is making the sensor go bad....if that's even possible.
Agree. The root cause of the problem is still unknown (see below :( ).


Dealer called me today, and said that a tech took the jeep off-road on a bumpy rutted road. The tech did not trigger the error lamps on his drive, and believed the jeep to be fixed.

I asked the SA if he was confident that the jeep was indeed fixed, and he did agree that the matter was resolved to the dealer's best ability.

The error lamps illuminated on my drive home, so I will now have to schedule the fourth repair appointment for the same problem.

My understanding of the AZ Lemon law is that if the fourth attempt to repair the problem fails, I can seek legal relief.

But, that is not my desire. Problem is that I am no longer confident that the dealer will find the root cause this 4th time.
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