This ECU arrived for regular socket work. The customer had examined the ECU board himself before shipping and stated that he didn't see any leakage. When we received it, we had a different opinion. Unfortunately, without examples to clearly illustrate what to look for, the untrained eye can easily overlook what we might consider a very obvious case of caps leakage and corrosion.
Look carefully at the second picture! That's an example of one of the more difficult leakage issues to identify. On the 1G ECUs, there's a large metal heatsink bar running along the width of the ECU near the white harness connector block. If caps leakage works its way up underneath that bar, the bar has to be removed to properly clean it all. That time adds to the repair and the leakage can be very hard to see at first. If left, it will continue to eat away at components until the ECU fails.