Any Experience With This Type of Problem?

[arcticfox2005]

Our toad, an '04 Jeep Wrangler Rubicon. Check engine light has come on and gone off by itself twice and is now on for a third time. Had it scanned and diagnosis was "losing power intermittently between PCM and TCM" (engine computer and transmission computer). There were 3 codes.

The shop said finding the problem could be tricky because of the intermittent business. The third time it happened, I was 20 miles from home and pulled in for an oil change. When I pulled out the light came on and the tyranny (4 speed auto) would not shift out of 2nd. Had to drive home in 2nd, using the shoulder as much as possible. I stopped at the post office and turned it off. When I came out and started home, it shifted normally.

Therein lies the problem. Would a Jeep dealership have a more specialized system to track down the problem or would the shop where I had it scanned be okay? The shop is large, well equipped, and has a good reputation. Since it is now shifting normally, is there a chance for a fix?

Any opinions or experience?

Bill

 

[Optimistic Paranoid]

I think for questions like this, you are better off using Google to find a Jeep owner's forum and asking there.

Having said that, I will mention that an electrical guru whose skills awe me has recommended a contact cleaner called DeOxit 5, which he calls a near magical problem solver.

I was having a problem with a outdoor temperature sensor that wasn't providing a signal to the weather clock in my bedroom.  I tried putting in new AA batteries, nothing.  The battery contacts in the sensor were bright and shiny, but just for the hell of it, I sprayed them with DeOxit.  Like magic, when I put the new batteries back in, it started working again.

If I was having you problem, I would unplug the PCM and TCM and spray the contacts and the plugs with DeOxit.  Absolutely can't hurt anything, and it wouldn't surprise me if you 'intermitent' problem magically goes away.

https://www.amazon.com/DeOxit-Cleaning-Solution-Spray-spray/dp/B07CG8YVFN/ref=sr_1_3?ie=UTF8&qid=1535996242&sr=8-3&keywords=Deoxit+5

 

[Arch Hoagland]

On a trip when we were 3,000 miles from home the alternator went bad on my Lexus toad. One of the problems it created along with not charging the battery was it caused shifting problems with my automatic transmission.

I'd charge the battery overnight and all worked well until we started driving back to the RV after visiting relatives in the evening and turned on the headlights. Right away the transmission would go goofy. 

I'd suggest checking your electrical system.  Especially the alternator as that what was causing my problem.

 

[kdbgoat]

Yep, De-Oxit is close to magic on connectors and such. I learned about it years ago when messing around with vintage stereos. It's the best thing in the world to clean up potentiometers.

 

[John From Detroit]

YOu need two things to help diagnose..
FIrst who is your Cell Phone provider?????

T-Mobile, has "Sync up and drive" AT&T has a competitive system and I think Verizon does as well though I'm less familiar with their line up.  This "package" consists of an app on your phone and a bit of hardware you plug into your OBD II port. it's also a hot spot. But .. I have some reasons for not loving it.  You pay a monthly 2nd line fee.

The other is a OBD II to Blue Tooth adapter.  This also needs an app like TORQUE on your Smart Phone (mine is an android)

BOTH sync the phone with the vehicle. then read and record codes as they come and go. EVEN if a code "Goes away" when you turn off and restart the phone's log file may retain it. (I believe it does) your technician can scroll through the log.

TORQUE can also (With the proper adapter) CLEAR the codes. this may have allowed your tranny to shift.

I have had ONE TIME the engine control computer and the dash display computer did not sync.. Just once.  Shut off. Re-started. all fine.