We have a problem with one of our trucks. It's a 2007 ford f-350 with the 5.4L and auto trans. Long story short, the battery was disconnected, the grey and white connectors mounted to the driver's side inner fender by the abs module were unplugged, then the battery was reconnected, but the guy forgot to plug back in the connectors until after the battery was reconnected. (you know where this is going...ZAP!...) Anyways, they tried starting the truck afterwards, but it would just crank over but not start. They disconnected the battery, and reconnected it again, and then it started.

NOW... After driving the truck for a little while (trans temp at N.O.T.), the tow/ haul light started flashing indicating a problem with the transmission, and the truck goes into some sort of limp mode (only 5th gear). Reading the datastream, it shows that when this happens, the "PCA SOLENOID A" show a fault and goes "SHORT TO GROUND" and shows 0.0 amps indicating full line pressure. This solenoid has since been replaced along with the internal wiring harness for the solenoid pack, so it's not the solenoid causing the problem. It seems that the computer notices a different problem, and "forces" the PCA solenoid to apply full line pressure in 5th gear, hence going into "limp home mode". Turn the key off, start it back up, light goes out and problem goes away for awhile

On top of that, we have 2 DTC's--PO748, AND PO962-Both indicating a "PCA SOLENOID CIRCUIT PROBLEM/ SHORT TO GROUND".

So, what it sound like is that when the connectors were plugged in with the battery connected, it "scrambled" the transmission control module. The only thing I don't understand is that the tranny will set this problem at differrent times/ pressures, rpm's, etc. It's totally intermittent, but happens often. At least once every couple of ignition cycles.

Any ideas?

Thanks in advance, Scott

 

First thing I would try is to disconnect the battery again and let the voltage bleed down (turn on headlight switch with battery dis-connected). Re-connect the battery and let the computer(s) relearn the stragedies. You'll have to run it through about 5 or 6 "drive cycles". Start, run it up to 55, come back to shop/home. Turn off. Do this 5-6 times and see what it acts like then....If the prob goes away, great....if it doesn't..... continue troubleshooting.

 

I agree with BPofMD. maybe de-juicing the entire system and starting over will finally clear it.

If not then i would inclined to think that you have a TCM issue.

 

Yeah, I hear what you're saying. we did the reset procedure on the battery a number of times, but we haven't driven it that much after we've replaced the solenoid. It's hard to drive it though when it goes in to limp mode as we're smack dab in the middle of the city, and as you can imagine, it's hard not to back u[p traffic when it's stuck in 5th as you're takin off from a light