Ryulick

Hello all I have a 2004 F150 5.4 auto trans with 196k miles. It started to have an intermittent “TRANSMISSION MALFUNCTION” display but would drive normal. I thought it was just a bad connector that’s above the ecm/pcu on the firewall. The clip was broken which allowed moisture/debris in. Cleaned it up and put some dielectric grease in it. It’s secured tight and wrapped in electrical tape. Seemed to do the trick however now I have the same display but feels like the truck gets stuck in OD or 4th gear when I first pull away. It stays in it for about 10-15 seconds then goes to second gear and stays there until i stop again. It doesn’t matter what speed I go to just more of a time thing. I had a trans problem at about 140k with similar symptoms. I ended up finding a broken clip on the valve body. Pulled out the metal pieces, new servos, new clip, new internal harness (the hard plastic one), new fluid and a new filter. After that it worked great until this issue. I found that fix about the clip on here after the shop said I needed a new trans. It’s throwing codes p0743 TCC solenoid circuit fault, p0750 shift solenoid A, p0755 shift solenoid B, p0962 pressure control solenoid, p0141 o2 bank 1 sensor 2, p0161 o2 bank 2 sensor 2, p0351 ignition coil A. The last 3 came on at the same time as the trans issues but who knows if that was just coincidence. The engine runs fine.

I do think it’s an electrical issues because of the codes about and the first time I saw the trans display the malfunction (this time around) was after driving through a puddle fast (kids love it). Any ideas?

needsmoarturbo

If fuse 33 is blown it takes out all those things you have codes for, so that would be the first thing to check.

Ryulick

I checked the fuse and it was good to go. It also doesn’t matter if I put it in first or second with the gear selector. It doesn’t change gears and just stays in second

needsmoarturbo

I dunno. I'd triple check fuse 33. Makes the most sense for that to be causing your issues.

Ryulick

I went ahead and switched out the fuse hoping it was going to be it. Unfortunately I wasn’t so lucky. I still think it’s more of an electric problem I just don’t know where it could be

redfishtd

There is an electrical connector to transmission -recently a guy had a rebuilt one that had problems ,it ended up being connector problem . He had it the shop retest the transmission first but they failed to check the connector, Could be rodent damage also .

Ryulick

I just checked a few of the connectors. There was one that was by where the shift cable goes into. I didn’t count them but from what I remember it looked about 10-12 prongs. First I pushed down to make sure it was connected and it was. I pulled it out to check and the black insert that goes between the prongs came out. Everything looked clean inside though. I put some dielectric grease on it and put the insert back. Plugged it back in and it’s still throwing the solenoid codes. I know there’s a hard harness inside the trans but that wouldn’t explain why it only acted up at first when it was wet. I checked the wiring from the computer under the hood and to all the connectors. There’s just a 1’ section that runs behind the motor that I can’t see

needsmoarturbo

How about a grey connector near the pcm that has 12 pins? That's where the power from fuse 33 runs through on the way down to the trans and the O2 sensors. Make sure it's clean inside and tightly connected.
I think the connector on the trans for the solenoids is on top of the trans but don't quote me on that

Ryulick

That’s the connector I was talking about in my original post. The clip the holds them together broke. I had one problem where I went through some water and caused and issue after it broke. I cleaned it up and made it tight. No issues after that. When this issue popped up that’s the first thing I checked. I cleaned it all out, put some dielectric grease it and and secure it tight. I’ll attach a pic just to make sure we’re talking about the same one. It’ll be above and slightly to the left if the PCM in the pic wrapped in tape

Ryulick

@needsmoarturbo @redfishtd so there was the same gray 10-12 pin connector on the passenger as there was by the shift linkage. It was hidden behind a heat panel I missed. I was able to pull that one out easily and was dirty inside. Cleaned it up, greased, secure it tight. I also found a really bad grounding strap connection. I touched it and it fell apart. This was in the body a little further back behind the front passenger side wheel. I’m going to put that ground strap somewhere else and see if it helps too