42RLE transmission acting goofy with P0700 code

42RLE Trouble Shooting Guide
2005 Service Manual (L/R circuit is T20 16DG/WT)

P0750-LR SOLENOID CIRCUIT (translates to 1st gear and reverse)

You’d need a special scanner and software to test the solenoid pack, but you can do some trouble shooting on your own.

Though this is a solenoid code, don't jump to the solenoid pack being the source of the issue. It could also be ground, power (including fuse or relay), a wire shorting to ground or a dirty solenoid connector. Something to keep in mind about the 42RLE solenoids is that they receive battery power through the #5 20A fuse and the transmission control relay in the PDC when the ignition is in the ON/RUN position. Any interruption to power or ground will set a code and can also make the transmission act up

Start by verifying that the fluid level is correct. Check with the the engine running, transmission in Park or Neutral.

You can also check that the fuse and relay are good and free of corrosion, even swap the relay with another.

After that start inspecting the wiring harness. In the service manual you want to go to the Wiring section, then Connector Pinouts.

Looks like the L/R wire comes out of the PCM’s 4th connector (on the right), runs to the passenger side of the valve cover, down the side of the engine block and back to the passenger side of the transmission where you’ll find the solenoid pack connector.

The wiring harness is known to rub on the A/C receiver drier as well as the engine block. If the wiring harness is routed behind the coil rail, it will rub against the block as the engine mounts flex.

I would take a real good look at the wiring harness. If you have a multimeter, you can also test continuity from the connector at the PCM to the connector at the transmission.

Beyond the above, a shop can test the solenoid pack. Hopefully it’s something simpler.
 
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oldditchdoctor said:
Sunday PM, on my way home from work, my transmission started slipping. Within a mile, or so, I noticed that the slipping was worse and that the transmission sounded like a power steering pump low on fluid. I managed to make it the last mile home, checked the fluid and it was clean, and full. I scanned the codes, P0700, and called a buddy that worked for Jeep.
He said to reset the PCM, I followed the instructions he gave. I did so and it still makes the noise, and slips. It isn’t stuck in 2nd gear, but it is slipping a lot!
I am thinking that he is correct in saying that the solenoid block is messing up. I have not had an issue at all, that I know of anyway, until Sunday!
Any ideas?
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P0700 is a catch-all generic transmission code that doesn't give any real information. Plug in an external code reader and see what code(s) the transmission is generating then post them here.

I had the same P0700 code two years ago and once I plugged in an external reader I got a more helpful code. I eventually fixed the issue without having any automatic repair experience. It wasn't easy but but it wasn't mind boggling either. Basically replaced the solenoid pack and installed a Transgo Stage 1 tranny kit for good measure. It has been flawless since.
 
wraith1516 said:
thats the plan I HATE ALL THE ELECTRONIC SHIT IN A JEEP IF IT CANT BE FIXED ON THE SIDE OF THE ROAD I DON'T WANT IT ON MY JEEP
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You're in the wrong forum if you are going to continually bitch about everything in a TJ. Ever fix a blown axle, manual transmission, transfer case, engine, etc. on the side of the road?
 
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Michael Alzen said:
Update: I reset the PCM and test drove it for ~20 minutes and it didn't act up. I want to spend more time driving it to test don't have time now. Does it seem plausible it's the PCM?
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05/06 automatics have software bugs in the computer. If the problem comes back after that reset it's probably from that software issue the factory never fixed. Give Mark a call at www.wranglerfix.com and talk with him about the problem. His company found and fixed those issues.
 
Jerry Bransford said:
05/06 automatics have software bugs in the computer. If the problem comes back after that reset it's probably from that software issue the factory never fixed. Give Mark a call at www.wranglerfix.com and talk with him about the problem. His company found and fixed those issues.
Click to expand...

Thanks Jerry,

I spoke with Mark earlier today and ordered a PCM but we're not 100% that'll fix it. I'd love if that was the fix. I spent all afternoon reading horror stories of people with this problem for years and thousands down the drain.
 
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Michael Alzen said:
Thanks Jerry,

I spoke with Mark earlier today and ordered a PCM but we're not 100% that'll fix it. I'd love if that was the fix. I spent all afternoon reading horror stories of people with this problem for years and thousands down the drain.
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Great, I sure hope it fixes it. Good luck! 🤞
 
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Jerry Bransford said:
You're in the wrong forum if you are going to continually bitch about everything in a TJ. Ever fix a blown axle, manual transmission, transfer case, engine, etc. on the side of the road?
Click to expand...
catastrophic failure aside you would be surprised what i have fixed on the side of the road and yes i have fixed an axle on the side of a dirt road in a piece of shit chevy truck but all Chevy products are just a piece of shit looking for the most inconvenient place and time to break down
 
Michael Alzen said:
Thanks Jerry,

I spoke with Mark earlier today and ordered a PCM but we're not 100% that'll fix it. I'd love if that was the fix. I spent all afternoon reading horror stories of people with this problem for years and thousands down the drain.
Click to expand...

It’s not your PCM. You should have done some trouble shooting before throwing a $600 part at it.
 
I had those codes, plus one more that I can't remember and the hard shifting from 1-2 in my '06. Disconnecting the battery temporarily fixed it. The reset intervals went from months to days. A new PCM from @Wranglerfix about a year ago fixed it.
 
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MountaineerTom said:
I had those codes, plus one more that I can't remember and the hard shifting from 1-2 in my '06. Disconnecting the battery temporarily fixed it. The reset intervals went from months to days. A new PCM from @Wranglerfix about a year ago fixed it.
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In a previous thread you said you had P0218 and P0714.

https://wranglertjforum.com/threads/05-lj-transmission-42rle-codes-p0740-p0218-p1775.32407/
MountaineerTom said:
Well...it did. I had P0218 and P0714 TCM codes for the transmission and one other that I can't remember right now. P0218 is an overheat code. Mine wasn't overheated according to my trans temp gauge. The Wrangler fix PCM has been in my '06 auto since August 2019 and has had about 1400 miles on it with no other codes or hard shifts.
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Faulty temp codes P0218 and P0714 and a hard 1-2 shift after the Jeep has been parked for a while are the most common PCM issues.

I expect this will be the DG/WT wire is shorting out on the block or the solenoid pack had failed.
 
Jerry Bransford said:
Puzzle me this then. How could resetting the computer, as he did, stop his symptoms if they were caused either of those?
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I wouldn’t trust one 20 minute drive to prove definitive resolution.

The PCM tests this circuit periodically.

The Low Reverse (LR) is monitored at initially power-up, then every 10 seconds thereafter. The solenoids will also be tested immediately after a gear ratio or pressure switch error is detected.

Because the circuit is not continuously monitored, the wire may be rubbing against the block at times when the circuit is being actively monitored, at least so far.
 
AjRagno said:
It’s not your PCM. You should have done some trouble shooting before throwing a $600 part at it.
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I'll do more troubleshooting but I'm short on time and wanted to get that part on the way. I have had occasional hard shifting from 1-2 when cold back in the winter and after talking to Mark it seemed a likely enough possibility that my PCM is failing that it's worth ordering and testing it out.

The 20 minute drive definitely wasn't enough to convince me either, but it was enough combined with talking to Mark that I went ahead and ordered the part. I'll update this thread as I progress through troubleshooting and certainly when I find the culprit.

Edit: I legitimately appreciate yours and everyone else's input on tracking down possible causes.
 
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Update: Drove for 45 minutes before I could reproduce the problem, stopped in a parking lot and reset the PCM and the problem immediately came back. It's a much cooler day today and I couldn't get the trans to 180, but the fact it took so long to make the problem return and then it was immediate after resetting the PCM and not letting anything cool makes me think it's heat related.

This time the problem was it struggled to downshift in a parking lot.

@AjRagno I did check the fuse and relay. The relay looks like at some point in it's life one of the terminals burnt a bit so I'll probably look for a replacement for that either way.

With this updated test info would you still bet on a wiring issue or the solenoid itself? Seems like if it was the PCM then resetting it would have prevented the problem for a while at least, or am I oversimplifying that?
 
Sort of related; does the torque converter only lockup in overdrive? Curious if driving with OD off puts torque converter in a constant slip situation, and heat up more than normal.
 
I think that you should inspect the wiring harness as I’d suggested previously. Look for chafing in the loom. If you find areas where it’s rubbing, open the loom up for closer inspection . The wire you’re looking for is dark green and white.

No need to buy a new relay for testing, just swap with the horn relay.
 
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