Better to be safe than sorry. Do the resistance test on the ISC motor just to make sure.

The problem with the ECU may be due to leakage from one or more capacitors on the board, or another component. It's a simple fix for someone who knows what they're doing and will cost $100 to $150 to have an expert do it for you. If the board can't be repaired, you can buy a rebuilt one for about $300. Good luck.