I bought this 2005 F150 with 4r75w trans issues. It had no OD and was slipping. I rebuilt the trans and found the following issues e clip broken on the OD servo, OD band worn, low reverse band really worn, burnt frictions and steels, 2 stuck valves in the valve body, and lots of metal and gunk everywhere. Also had a worn sun shell. The truck had no lights on before the rebuild except the trans malfunction light. The truck ran great.

Now after the rebuild I have the brake light and abs light on solid all the time. When the truck is shifted into drive the OD light blinks and the trans malfunction light comes on. I have no OD and no engine braking in manual 2. After driving a few minutes it throws a check engine light and goes into failsafe mode. The codes are p0705 trs, and once it threw a p2106 code forced limited power. I replaced the trs with a new one adjusted correctly and it made no difference. I can start the truck and put in manual 2 and drive and the trans malfunction light does not come on as long as I leave the shifter in 2. I also have engine braking as long as I leave it in 2. I figure the pcm does not see a fault if the truck is placed in manual 2 after startup and does not disable the OD, thus allowing the OD band to grip the sun shell.

I know the OD band is on the servo pin. I have checked all the electrical connections. I have checked all fuses. I checked the wiring harness on the passenger side by the manifold and it’s not touching or burnt. I checked the plugs on the pcm. I checked the plug on the vss on the rear axle. I’m at a loss. I am thinking with the p0705 code that there is either a short between the trs and the pcm or the pcm is bad. But why are the brake and abs lights on, maybe a bad pcm will set them? Hopefully someone can help. Thanks in advance.

-Chris

Here is a small update. I have no reverse lights. I cycled the shift lever thru from P to 1 and back and no lights or flickers. I need to check the harness from the trs to the pcm. There are 9 wires. Does anyone know the procedure to check this? Thanks again.

Another update. I rechecked the fuses, and I made a mistake the first time. Fuse 14 is blown. It blows when the ignition is turned on. I have tried the following.

Replaced the trs. Fuse blew when key turned on.
unplugged the trs and the fuse did not blow when the key was turned on.
unplugged heated pcv. Blew fuse when key turned on.
removed reverse bulbs. Blew fuse when key turned on.
I don’t have daytime running lamps. At least there is no relay in the BJB under the hood.
unplugged the driver door harness. Blew fuse when key turned on.
Unplugged EC review mirror. Blew fuse when key turned on.
Unplugged park assist module and speaker. Blew fuse when key turned on.

i need to test the other things on the #14 fuse circuit. If anyone has suggestions on what or how I should test something please let me know. I will find the issue and I will post a resolution. There seem to be a lot of posts without a resolution. thanks

-Chris

Sorry Hanky. That should have been the first thing I posted. I will edit the first post. It’s an 05 lariat with the 5.4 and a 4r75w trans. My best guess right now is that there is a short to ground in one of the 9 wires connected to the trs. I have verified power to the light blu/pink wire on the connector. From a schematic I found online I think that wire feeds power from fuse 14 to the ignition then to the trs. I am not sure how to test the other wires yet. Thanks

The harness inside the trans is just a hard plastic connector. No way to pinch a wire. It could be damaged internally though.
I am using a dmm and a test light. The schematic I found is for a 2006 to 2008 f150. I think it’s the same for the 2005 though.

ABS control module shares the #14 protection. Seems the only circuit not unplugged other than ABS on 14 was AC HP switch,, and the next potential load would be the integrated Trailer Tow Reverse Lamp relay in the CJB. If the relay was suspect, you could disconnect the pin from the CJB connector and recheck for the fuse fail. The other two, you might try a disconnect there....

Being there was no circuit protection fail prior to the disassembly, doesn’t seem likely for a component failure.

Thanks for verifying it. I need someone more knowledgeable than me to verify the following.

The trs is good because I have changed it out with 2 different new units and the issue does not change. The fuse only blows when the trs is plugged in. This means the short can only be on the trs circuit posted above, or on one of the signal wires from the trs to the pcm. Also, since the fuse blows instantly when the key is turned on and the truck is in park, the short will not be on the trs reverse circuit. The circuit is not completed until the trs is in the reverse position. The truck will start in park and neutral even after the fuse blows, so the wires to enable the starter in P and N are good. This leaves one of the remaining wires from the trs as the culprit.

Hayapower, I agree it seems like it’s not a component failure, but a short to ground in a wire. Please give me your opinion on my last post. Thanks