So my truck is older and it was handed down to me and i would like to keep it running because its in very good shape, but the transmission will keep popping a P0871 code, and at 176000 miles it might be on its way out, any ideas on how to fix it, Model is the 42RLE, if it doesnt seem fixable, should i swap if possible for the 45RFE or 545RFE if they fix (Truck model is a 2011 Dodge dakota ST 4x4 with the 3.7 V6)

 

That's a fluid pressure sensor.... "Sensor C" to be precise.... Not sure just how many your trans will have, but, I would think it is part of the solenoid pack??? Maybe??? Don't know if it is serviceable separately or not.

 

Thats the issue, i cant seem to pinpoint which part of the transmission keeps making the pressure go out of range, right now i drove home yesterday and it went away and ran fine, ive found a resposne that shows it can be pretty much be any part, going from the valve body, to the fluid being cold.

Thats why i was looking into what transmissions work aside from the 42RLE (ive heard its a nightmare reliability wise, so im surprised the truck has made it tihs far) and i dont know what the opinion of the 45RFE or 545RFE(with necessary mods toslot in the change for the 5spd)

 

Does your have the separate transmission control module??

 

would it usually be by itself for that model to a separate part of the electronics, I can check around the ecm/fuse box to find it

 

I don't know...... I am more familiar with the older full size trucks......

 

unfortunately I’m not an expert on car electronics, but from what I can find, there is no seperate transmission control module, I found the Tipm, and the fuse list from the manual lists powertrain control modules, but I can’t find anything of a seperate module, must be combined with something

 

Don't know if your vehicle came with any other 'meaner' transmissions.... behind whatever engine you have.... The separate module would have made life a lot easier, but, I suspect, changing your trans for something better is going to be a complicated exercise. They are purely electronically controlled, and all that programming is in the PCM, so far as I know, they don't separate engine from trans programming..... So, if you move to another trans, it's gonna have to be something that actually came behind your engine, in some application or other, otherwise, the programming won't be available....

Another option would be to 'upgrade' your trans via a rebuild, chances are good there are 'tricks' available to increase its reliability..... but, just off hand, couldn't tell ya what's out there.

 

The DTC is set if one of the pressure switches are open or closed at the wrong time in a given gear. If the
problem is identified for 3 successive key starts, the transmission will go into Limp-in mode and the MIL will
turn on after 10 seconds of vehicle operation.
Possible Causes
RELATED TRANSMISSION RELAY DTCS PRESENT
LOSS OF PRIME DTC PRESENT
(T9) OD PRESSURE SWITCH SENSE CIRCUIT OPEN
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
(T9) OD PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
TRANSMISSION SOLENOID/PRESSURE SWITCH ASSEMBLY
POWERTRAIN CONTROL MODULE


Theory of Operation
: The Transmission system uses three pressure switches to monitor the fluid pressure in the LR, 2/4, and OD elements. The pressure switches are continuously monitored for the correct states in each gear. Normal operation will
be experienced if no other codes are present. Transmission Control System will ignore the code. Limp-in condition
will only occur if DTC P0871 is present with a DTC P0706.

Thats straight from the factory service manual, section 21-186. There are three pressure sensors in the transmission solenoid pack. That is a known weak point on the transmissions that leads to issues after some time. When was the last time the fluid and filters had been changed? When my 2011 with the 42rle had issues shifting, that was the easiest thing to try and fixed the issues. How often does the code come up? Does it go into limp mode?

 

I got the truck handed down to me about a thousand miles ago so I can’t say for certain when the last time the fluid/filter was done, I did have a shop check it out after i added some in to check the whole truck after I got it and the fluid for the most part was still new and a little high because I added extra, no idea on the idea of the filter, usually the code will come up and stay there, but it went away on Sunday, The family member who handed it down said it was already doing that, it will throw itself into limp mode most of the time during the code, or after a really bad shudder but that seems to be fixed after throwing some shudder stop in