Bad PCM?

[RR5.0]

I have been having a serious issue with my 6r80 lately and I believe all signs are pointing to a PCM issue. From my datalog I am showing that all transmission solenoids are engaging when the vehicle is trying to shift from 3-4. I am also seeing the incorrect shift solenoid engagement for 1-2-3 as well. This only occurs once the car reaches operating temperatures.

I dont want to throw parts at it but this is my last resort. I'm at the edge of getting rid of the car because of this. I cant have a daily driver being down this long.

When ordering a new pcm from ford what information will I need to give them? Will my tuner be able to get a new file for me without putting the car back on the dyno?

 

[KPatrone]

As I was going through my 6r80 swap I ordered a new PCM from Tasca and ended up using a used one from a salvage yard that was the same year and model of my vehicle due to programming issues I ran into. Cheaper and easier alternative, just my .02

 

[wakebum2507]

Have you looked into a new lead frame connector?

 

[RR5.0]

I check the lead frame for continuity and got .1 ohms to each solenoid connector from its respective plug. This lead me to believe the molded lead was good.

Will using a pcm from a salvage yard cause any problems? Does it need to be reflashed or can i just load a custom tune on it and go?

 

[wakebum2507]

It should prob need to be reflashed

 

[NELCO]

I agree re flash it first, I had a failure and car would not run even though I re flashed it. It turned out to be my SCT tuner.

 

[RR5.0]

Where can I get a used ECU? My local pick n pull doesnt have any coyote mustangs...

 

[KPatrone]

Car-part.com

 

[RR5.0]

Do i need to get a pcm with the same part number or will any one for a 2012 auto gt work with a reflash?

 

[Turbo5.0]

Have you looked into a new lead frame connector?

I had a friend with some odd behavior in his 6R80 and ultimately ended up replacing the lead frame assembly (has speed sensors integrated into), and the big seal from the VB to case. I think one of the integrated speed sensors was shorting out causing all sorts of strange shift behavior, wrong gear etc... His was only acting up at temperature also.

Worth looking into. I think he may have seen some spikes in some logs of the speed sensors when they would act up. That is what led us towards the lead frame and did the trick with his issues.

 

[RR5.0]

I replaced the molded lead frame connector. This seems to have solved the problem! So far 30 miles with no issues!!

From datalogs it seems that my transmission turbine speed sensor was reading incorrectly.

Thanks all for the help!

 

[RR5.0]

Problem just came back. Getting beyond frustrated with the car at this point. Ive tried everything I can think of.

Anyone else have some input???

 

[H-TownMachI]

Do you think your tune file could somehow be corrupt? Have you tried reloading it or having your tuner send again.

 

[RR5.0]

I have loaded three seperate tuner's files and they have all performed the same. I would try the stock tune but the car has id1000s and a paxton...

 

[RR5.0]

Did some more testing tonight. With the key on, harness plugged into the pcm, I am getting 25.6 ohms at Shift Solenoid E. With the key off I get 0.L Ohms. This leads me to believe that there is something internally wrong with Pcm. I am going to try and find a used one locally at the salvage yard.

 

[dennisn]

You need to find out exactly what you should be reading and when. Other than that your just guessing. You checking resistance to chassis ground? My guess when ign off it'll go to zero cus voltage is going away. That very well may be normal.

 

[RR5.0]

Every other shift solenoid gives me 0.L with the ignition on. I am assuming that every shift solenoid should have similar resistances. The only other wires i get with those resistances are grounds for the transmission. I do not see any reason a shift solenoid should be grounded out with the ignition on.

 

[dennisn]

Every other shift solenoid gives me 0.L with the ignition on. I am assuming that every shift solenoid should have similar resistances. The only other wires i get with those resistances are grounds for the transmission. I do not see any reason a shift solenoid should be grounded out with the ignition on.

with key off if it's an open line. "OL". That doesn't sound like a short. Im not saying your pcm is good. You almost need another car that you can check to see what your supposed to get. Kinda odd though it's the same selonoid you changed and thought you were having issues with.

Your grounds for your trans should be very low resistance. 0-1. Are you using a decent meter not a harbor freight special? That could make a difference also in your readings. Trying to help you brotha.

 

[RR5.0]

That was my first thought with it being an open line with the key off there can be anything wrong. However it grounds out with the key on which confuses me. I have a friend who has a 14 automatic that I might be able to test and see what the readings are supposed to be, thought it could be a while before I have that chance.

I am using a Snap On Digital Multimeter for all of my tests.

Also I have located a used PCM locally for $150, three of them actually, just have to call and confirm that they are for automatic transmissions.

I appreciate the help man! Its becoming a real struggle as I have replaced the Shift Solenoid, Lead Frame, reflashed the PCM, and checked the wiring multiple times with no positive results. The only thing that came close was the lead frame replacement and that only lasted 3 days.