Shifting problem in my Jeep

Factual Questions
1

Ongoing intermittent problem
Every so often my Jeep decides to drop into passing gear and not shift out. Stopping the car, turning off the engine and restarting clears the problem. With very few exceptions it is going uphill at altitude. I replaced the MAP sensor and putting in a clean air filter helps but it still happens and sometimes I can’t go 3-4 miles after the reset without the problem coming up again.

This time I was smart enough to pull the code and apparently it is the heater on the oxygen sensor - bank 2 sensor 2.

Would that cause the problems I’m having?

2

year/make/model would be extraordinarily helpful.

3

I don’t know about your problem, but I had a shifting problem in my 1999 Cherokee once. It would go to third, but not shift into fourth/overdrive. Turned out to be the computer, which was replaced under warranty.

4

Sorry I thought I put that in
2005 Jeep Liberty Renegade

5

ah, your Jeep was built during the Dark Days of Daimler. Best of luck.

6

I know SDMB is the bomb and all, but some questions are better asked in other places. Jeepforum.com is a very good forum to get technical questions answered. Your year Liberty is the KJ series by the way. You’ll need to know that to get to the right subforum.

7

No.

8

Gary T, I always value your car advice. I think it’s a sensor since the problem (temporarily) goes away when I restart the car.

So if it is not the O2 sensor, why does it come on? If not the sensor or MAP or dirty air filter and only happens under very specific conditions, what could it be?

9

And I think it is slipping out of overdrive but in that case why would the P code indicate a sensor?

10

The symptom you’ve described sounds like the vehicle goes into the “limp home” mode, described here. There are various problems that can lead to this; I’m sorry I don’t have a list of what they all are.

I assume the code you found was P0161. While I can’t say with absolute certainty, I’d be very surprised if this would result in engaging the limp home mode. The oxygen sensor heater lets the sensor give useful readings in one or two minutes after start-up, instead of in five or ten minutes by waiting the component to heat up naturally. So if the heater fails, the sensor can still work, it just won’t work properly quite as quickly. I find it hard to imagine that this condition warrants limp home mode.

I strongly suspect that there are other codes, related to either a more serious engine performance problem or to a transmission problem. I can’t help but wonder if the code-reading method you used does not give a complete readout. If there are transmission-related codes, I would expect to see a P0700 indicating that, but the specific codes would have to be read with a scan tool that can communicate with the transmission control module.

I’m sorry to say I think the odds of us nailing the problem with only the info provided are quite slim. I think it’s going to take some more thorough testing of the vehicle to get anywhere.

11

It was code P0057. Ok. Looks like I need to head to an auto parts store and get the code read off the computer.

12

www.jeepGarage.org is also a good place. There are many different Jeep forums but jeepGarage and jeepForum, in my limited experience, are among the better ones I’ve come across.

13

Pulled the code using the Jeep key trick. Yes I screwed up the first time and got the firmware version (5.7). It is the generic p0700 for something is wrong with your transmission. The CEL is now out so I’m wondering if the actual transmission code is still in there.

14

I expect the tranny code is still in the TCM. I don’t believe the P0700 by itself will turn on the CEL. A visit to a reputable transmission shop is probably in order.