4l80e pressure control solenoid

[thompsoncustom]

hello, I have a new to me humvee with the N/A 6.5 and 4l80e transmission and have been changing fluids and doing some little maintance and driving around town. everything seems good except the transmission seems a little confused if it should shift up or down in overdrive.

found on here how to jump the TCM with a wire and got code 73 (pressure control solenoid)

my question is I see a couple different PCS online for the 4l80e and was wondering if this is something I have to pull and match or is there a replacement one out there for the humvee specifically, thanks.

 

[Mogman]

Welcome to the SS forums!!
Have you gone through the troubleshooting for a bad connection? is there any fluid in the transmission harness connector?

 

[thompsoncustom]

I have not thanks for that. I should be able to do all that expect install the test cable as that's not something I have. Figure while I'm in there I'll pull the valve body and clean it up.

 

[Mogman]

You don't need the test cable just read the resistance from pin C to D, the test cable just makes it easier.
You can also unplug the J1 connector at the TCM and should have the 3.5-5.2 ohms from K to G on the cable connector.

 

[thompsoncustom]

Thanks your post are a lot of help.

 

[thompsoncustom]

You don't need the test cable just read the resistance from pin C to D, the test cable just makes it easier.
You can also unplug the J1 connector at the TCM and should have the 3.5-5.2 ohms from K to G on the cable connector.

pulled the j1 connector at the TCM and k and g are not in use. was unable to get the connector off at the transmission just not enough room to get my hands up in there.

 

[Mogman]

You are looking in the wrong place the ones you want are on the second to bottom row, LOWER case G and K

 

[thompsoncustom]

you are indeed correct should be much easier now that I see the right ones, I'll have to do a little more playing around and see if I can get the tranny plug off or lower the trans enough to get at it for the rest of the testing.

 

[Mogman]

you are indeed correct should be much easier now that I see the right ones, I'll have to do a little more playing around and see if I can get the tranny plug off or lower the trans enough to get at it for the rest of the testing.

So I assume you are not seeing the correct ohmage (open) at that plug?
It certainly can be an open or shorted solenoid but it usually is an open in the wiring, the internal trans harness seems to be a popular issue.
If you cannot get to the plug on the trans to check (why there is a "test" plug) you can check for continuity in the harness between the trans plug and the ECM harness plug, if all looks good there move into the trans pan and see if it is the harness or the solenoid itself.
You might also try some contact cleaner on the trans plug and harness connector, plug it back in and see if the reading at the TCM connector changes before dropping the pan.

 

[thompsoncustom]

I did check the lower case g and k today and it came in at 4.4 ohms so that's reading good.

 

[Mogman]

I did check the lower case g and k today and it came in at 4.4 ohms so that's reading good.

That is what the TCM is looking for, I would stick it back together and see if that code comes back.
Code 73 is the TCM saying it does not see the correct resistance (circuit error) if the resistance is correct then the error is in the TCM or the wiring between the J1 TCM connector and the TCM
It could also be an intermittent circuit/connector problem, or it could be the solenoid opening up when it gets hot.
If the code comes back check the ohms again at the J1 TCM connector when the trans is hot.