Limp Mode - Error Code P1776

[Andrés Uribe]

I am the owner of a 2006 WRANGLER RUBICON TJ with a 4.0L engine and a 42RLE automatic transmission, with only 27,000 miles.

For the past few months, my Jeep’s transmission has been going into “Limp Mode”, usually when in fourth gear, after approximately one hour of driving. When this happens, the transmission gets stuck in second or third gear until the error is cleared and the check engine light turns off.

The error code that appears when scanning is P1776:

“IGNITION RETARD DURATION FAULT. Solenoid switch valve latched in the left rear position; ignition retard.”
I have already tried everything that has been recommended, but the problem persists:

1. Transmission fluid level check – OK.

2. Inspection of the entire electrical wiring – Done.

3. Replacement of the complete solenoid pack – Installed a brand-new one.

4. Replacement of the PCM – Installed a new one from Wranglerfix.

One additional detail, which may or may not be related, is that this issue started occurring after replacing the engine cooling system radiator with a used one that appeared to be in good condition.

I am running out of ideas and would greatly appreciate any input from the experts in the group on what else to check.

 

[macleanflood]

Did you flush the transmission cooler inside the used radiator before you installed or ran it?

I imagine that used radiator transmission cooler was full of shrapnel and you pumped it through your transmission...ending your transmission.

@hear is going to fly to Oregon and help me rebuild my 4R100 on my F250 if it ever dies =) I'd trust his opinion...

-Mac

 

[hear]

Well if I'm supposed to act like a transmission shop.....

"I'd recommend a full rebuild."


But seriously, the thing I love about the 32RH is that I never need to consider that the computer might be causing part of the malfunction. With the 42RLE there are so many more variables. And honestly, I don't have anything concrete to offer in the way of troubleshooting. The P0700 is a basic TCM issue, usually coupled with another code, so I wouldn't worry about the P0700, it will most likely clear once you fix the P1776. I don't see any way it's related to the radiator change, unless there is a problem with the trans cooler section....I suppose that could explain why it takes a while for the problem to appear; it needs a sufficient amount of heat buildup to trigger the issue? You'd need to be running a trans temp gauge to have any idea if this is the case, and the conventional wisdom is that on this transmission you absolutely should be running a temp gauge. So there's that.

My default answer at this point would be to inspect your wiring, and (perhaps) obviously verify that your solenoid is actually working. You can pull it out and put 12V across it. You should hear it click. Wiring harnesses at the age & level of abuse tend to develop cracks & shorts that can lead to odd things. But if it is repeatably internmittent and somewhat timing based, I'd tend to be less suspicious of the wiring.

A quick google says it could be the range sensor, but idk if the 42RLE has one (the AW4 in the Cherokee does, 32RH does not), and then there is always the generic "you've got some schmutz in your valve body."


@macleanflood I haven't been to OR in a long time... I miss the smell of that paper mill in Eugene. When are we doing this?

Also, what are you doing up at 4:30am???

 

[macleanflood]

When are we doing this?

Also, what are you doing up at 4:30am???

When it breaks of course!

Getting ready for work at 4:30 AM. Currently deployed to a secret location in Southern California and can't mention anything on social media. But think of what I do volunteer wise and you might figure it out.

-Mac

 

[hear]

When it breaks of course!

Getting ready for work at 4:30 AM. Currently deployed to a secret location in Southern California and can't mention anything on social media. But think of what I do volunteer wise and you might figure it out.

-Mac

happy ending massages?

Not the hero we deserved, but the hero we needed.