At 02:32 PM 7/8/2012, neil n wrote:
>Seems what I saw as corrosion may be the surface coating lifting away
>(or ? process) allowing the copper trace to be seen. If that makes
>sense.

That's entirely plausible.  My stupid brain won't feed me the name of
the stuff, but it can flake sometimes.  If you're feeling anal you
can paint it with nail polish.  Keeps the copper bright.  The 2.1l
case gives pretty good protection but isn't really protected against
humidity as far as I can see -- unless that vent is really an
overpressure valve.

>Interesting. There were quite a few of these spots.

Every 2.1l ECU I've opened has had some rework, I think.  Some may be
from the production line.  The Bosch units in particular have had
very bad-looking solder, though the 022D ones seem better.  If
someone has repaired the unit he may have put the silicone goop on to
try to help the interconnects.  I don't know whether it will actually
help, but it will make them harder to resolder.

>I thought it might be a D suffix ECU but don't see that in the PN on ECU case.

It would be there.  There will also be a thin whitish plastic shield
wrapped around the entire inner assembly, held on by pop fasteners.

>I don't recall seeing components on backside of either board or a heat shield.

You'd notice the shield.  It's a heavy can covering the entire small
board.  Electrical, not heat.

Yrs,
d