Back in March when towing a trailer (approx weight: 8K) I was using Tow/Haul and it started flashing within about 5 minutes after engaging. I had the codes checked and the following came up:


P0700 & P0751


I continued to drive the truck not noticing any shifting issues. I have not pulled the trailer since. I recently had the FICM rebuilt and installed an Edge CTS. I noticed that all codes were cleared since the battery was removed for a few days. But just yesterday I was coasting down a small hill when the Tow/Haul seemed to engage itself and both of the codes above popped up again. I also noticed a few minor misshifts/jerky shifts for the next mile or so.


Drove the truck roughly 50 miles since with no apparent shifting issues. Was planning on draining the transmission fluid and changing this weekend. I have read a few forums posts on these codes (particularly P0751) and have noticed many mention chaffed wires/bad electrical connections. What in should I be looking for in particular? And if a selenoid needs replacing... what part # should I be looking for? Are they difficult to replace? I was planning on dropping the pan and looking for debris as well... and changing the internal/external filters while I was under there


Any help would be greatly appreciated!

 

P0751 means one of the solenoids (solenoid A) is mechanically stuck. Chaffed or damaged wires will NOT cause this code. The only way this code can set is if the armature inside the solenoid is physically stuck.

I don't have a diagram to share with you showing which of the seven solenoids is Solenoid A. They are easy to change once the pan is off.

Don't worry about P0700. That's a code that sets when something is wrong, but the PCM can't determine what it is. Most likely if you replace solenoid A that code won't come back.

 

In aother forum I was sent a picture of the solenoids... I replaced the one that was labeled SSPC-A... after a little research I found that it was the SHIFT SOLENOID PRESSURE CONTROL A... which makes sense based on the DTC I was getting.

Unfortunately after replacing and putting everything back together I am still getting the flashing tow/haul light and same DTC when I turn tow/haul on.

P0700 - comes on shortly after clearing codes
P0751 - comes on shortly after engaing tow/haul

In the picture there was another solenoid labeled PC-A. Which I assume is just PRESSURE CONTROL A? Should I attempt to change this one out?

I also checked all the wiring and it looked good.... didn't see any chaffing. No sediment or metal pieces in the pan... fluid actually looked very clean still ... solid red no browning.