I don't know about the ECU used in the VW but I repaired Bosch ECUs used in Mercedes by inspecting the solder joints with a eye loupe and marking any questionable joints with a marker.

Then I would remove coating from those joints, remove the old solder and then re-apply solder. When done I would re-inspect the solder joints I had done with a eye loupe.

I did it this way because you can actually cause a problem by just adding solder to existing solder joints. You could create a fractured or disturbed joint where there was not one before or you could damage & crack or lift a pad.

Thanks, Tom Hargrave
www.stir-plate.com
www.towercooler.com
www.kegkits.com

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Lauterbach
Sent: Saturday, June 18, 2011 12:09 PM
To: vanagon@gerry.vanagon.com
Subject: Resoldering PCB on Bosch ECU for 1.9L engine

I plan on resoldering the critical connections on the PCB on Bosch ECU
for 1.9L engine.  Circuit board has number 2288325840-4/  on one corner.
As I understand, the critical points are where the pins from 25-pin
connector is soldered to the PCB.  Is this correct.  The board appears
to have been coated after the board was soldered.  Does this coating
give any difficulties for resoldering the pins.  Are there other points
that need to be soldered?

John
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