Resolved Pulled ECU with questionable SMD cap

[James92]

I pulled my ECU and have a questionable SMD cap under my 100uf 16v cap. I was going to replace my capacitors and also came across some stuff under my eeprom so I’ll need to investigate that but the SMD has me scratching my head. Insight from the community is much appreciated.

Reason I pulled was due to some irrational shut off and back on scenario, like a ground touched then came back to life. Went away for a little while but came mysteriously and figured I’d investigate the ECU. I get the CEL when I’m on position with key and can hear 1/2 clicks from the MPI (haven’t tested)

Edit: I did notice the burned pad, just don’t know why the SMD would bridge over the opposing trace.

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[steve]

There would have been a SMD cap (C14) a little closer to the front of the board between the two traces. (One is +5v and the other Ground). You can see it and some of the types of corrosion leaking caps cause in this picture. I'm guessing that due to corrosion the SMD cap needed to be moved because the normal place was damaged.

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Your ECU has suffered from leaking caps in the past and it's not clear how well it was cleaned and repaired which can cause delayed problems at a later date. It looks like you have a DSMLink board installed so someone also removed the EPROM and installed a socket. Again the quality of the work has a large impact on the longevity and reliability.

 

[1990TSIAWDTALON]

Send it off to ECMLINK.

 

[James92]

I agree it’s suffered some leakage, I wasn’t able to at the time to investigate since my MM was buried in other boxes so I zipped off the old caps and got a better look and seems like a couple of them has some of the traces repaired AND I noticed some corrosion forming under the eeprom socket so I zipped that off too and cleaned it all up with white vinegar and baking soda and soldered in new caps. Looks good as new. Drove this morning and seemed to perform perfectly again. We’ll see when it warms up how she behaves.

But I do see what you mean, closer looking at it I did see pads for an SMD ceramic cap; one side looked to have been a casualty. Appreciate the input, some times just discussing makes the path more obvious.

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