Need New PCM ?

[Tinkertech]

UPDATE:
I think I troubleshot the issue down to 1 chip on the PCM board. I always felt it was an intermittent solder connection on this board some where. Since I have an extensive background in electronics I gave it my best guess. The board is a real nightmare to work on, no schematic or any data and the board is over coated with silicon. also the board is RTV'd down to the case only allowing for me to see and work on the top side only. Reflowed the suspected chip and 3 days latter all issues are still gone. I will be running codes for the next week or so daily. We will see if it holds.

 

[Juice]

UPDATE:
I think I troubleshot the issue down to 1 chip on the PCM board. I always felt it was an intermittent solder connection on this board some where. Since I have an extensive background in electronics I gave it my best guess. The board is a real nightmare to work on, no schematic or any data and the board is over coated with silicon. also the board is RTV'd down to the case only allowing for me to see and work on the top side only. Reflowed the suspected chip and 3 days latter all issues are still gone. I will be running codes for the next week or so daily. We will see if it holds.

I have seen my share of broken solder joints.
Hope you got it!

 

[DieHarder]

Wow, getting it down to a chip without having a schematic to reference is outstanding; my hat's off to you. Here's to a successful guess.

 

[Tinkertech]

Well its been almost 2 weeks since I repaired my PCM that had the bad solder connections on a 48 pin QVN chip. I could never get a really good ides of what kind of chip it was even though I had the P/N. It seems to be a proprietary design by Motorola who also makes the board. Very little data on the chip only that it was for automotive emissions systems. Anyway so far the computer has been working great. I test for codes every day and none so far so I consider the issue fixed.

 

[DrProfessor]

I have a near identical issue and background (just less experience). I was narrowing down which component needs to be reflowed and I found your thread. You saved me a ton of time trying to find it myself! Thanks, I'll have updates if it works

 

[DrProfessor]

4 months and ~2.5k miles since the fix and no further issues

Personally, I found the repair easy, but I wouldn't recommend this for beginners. Brief rundown of what I did:

Removed polymer coating by cuting an outline of the work area with an exacto, then used tweezers to peel it off. Agitating with an isopropyl alcohol soaked brush helped clean the area before and after rework. Preheated the area around the QFN before switching to a hot air station. Applied flux all around the component and additional solder to the pins where needed.

Good luck to anyone trying

 

[Victorslik]

Hello all, another "first time" poster here. I am at the same point Tinkertech & DrProfessor were at. My TS'ing led me to a faulty output from the PCM causing my a/c comp function to be erratic. Paid the Ford garage the $155 diagnostic fee and they agreed, the PCM says it is sending the ground to the relay for a/c compressor to run but it is never making it out of the pcm, $1300 for after- market pcm installed by them. Told them to hold off I'm going to research a bit more & reading here again I find this. I've had experiences with multi-function relays having bad/failing solder joints before but those were much easier to access and much less critical components should I burn up the board trying to re-solder. I'm much more of a "wrench" than an electronic technician but do know somebody who has done some fine electronic repair for me in the past. We are not going to have the ability to look at this under a m'scope, maybe with a lupe. I'm wondering if Tinkertech or DrProfessor are around to help point us in a more exact direction for the purpose of "re-flowing" the soldered connections. Unquestionably I will be exploring this repair before buying a new PCM, pretty sure a P/O added a custom tune to this 06GT. I'd be really ticked off to pay up for any pcm and programming only to find car wont run right with a different pcm. Anyways, Tinkertech or DrProfessor???