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So I've had a dtc 452 for awhile I e been tracking doqn, thanks to subford and a couple others I successfully figured out that pins 3 and 6 were simply nor making a strong connection at the pcm. I get it working great and man was I happy after months of pulling my hair out she shifts perfectly.....but then... I go out one morning and she is right back to limp mode. I'm cussing a pissin mad... I check and double check and triple check the connection, and it's good.
So I open up the pcm to take a look and trace pin 3 and 6 to this chip. I'm gun shy about replacing it so I want confirmation from you wonderful ford peeps that this is burnt. Thank you!
Its on the left side you can see the burnt looking spots
Nothing there looks burnt to me, that's from the perspective of an electronics technologist with almost 20yrs experience troubleshooting electronic circuit boards. The brown spots are just solder flux residue which is probably hard and crispy and would scrape off if you were to try and clean it but that isn't necessary.
I might be inclined to clean it up though, if enough skunge gets built up over the years, it becomes conductive. Just for grins, since it's already out. A soft bristle brush and some naptha (lighter fluid) would do fine.
I cleaned it and it made no diff. Also it was the only circuitry in the whole pcn that had this appearence, that's why I asked... but if it's not the problem then I'm back to square one with squat and I got teased with a couple days of good shifting....
Would you have any suggestion on ohm testing the pins? I ohm tested pins 3 and 6 on the pcm and got 470000 ohms of resistance. I'd what the circuit should be so I have no way to find out unless somebody happens to know.
470,000 ohms of resistance to what? Also, I would not have cleaned or touched that. That is a ceramic-hybrid module, and those black "burnt" bits, are actually laser-trimmed carbon resistors. Touching them may have altered their values.
You should be checking continuity between the backside of Pins 3 and 6 (as in, from inside the computer) to the same connections up at the PSOM.
470,000 ohms of resistance to what? Also, I would not have cleaned or touched that. That is a ceramic-hybrid module, and those black "burnt" bits, are actually laser-trimmed carbon resistors. Touching them may have altered their values.
You should be checking continuity between the backside of Pins 3 and 6 (as in, from inside the computer) to the same connections up at the PSOM.
I will be checking that in a few but I'm willing to bet there is good continuity. The 470000 ohms was between pins 3 and 6 on the pcm. I was hoping there was some correct measure of resistance between them. The connector side tested good according to spec. I appreciate the insights. This truck seems haunted...
That's where I'm at... Theres no other logical explenation. It's gotta be the pcm as it is the only part in question
Keep in mind PSOM failure is pretty common with these trucks. If you know someone with an OBS truck, see if you can convince them to let you borrow their cluster.
Keep in mind PSOM failure is pretty common with these trucks. If you know someone with an OBS truck, see if you can convince them to let you borrow their cluster.
Cruise control still properly works which rules it out.
