During some aggressive taxi runs yesterday, we had 2 engine shutdowns which the GSU indicated as Watchdog. The ECU is mounted per on plywood with foam as recommended. No antistatic spray is used on wheels. The ECU was replaced, and another less aggressive taxi run was completed with no shutdowns. The manual indicates Watchdog shutdown is due to ESD. Does the Watchdog reading indicate a failed ECU? Is there an easy way to test the ECU that displayed the Watchdog? While replacing the ECU seems to have solved the problem, I am concerned that there may be another issue that just wasn’t encountered on the last taxi run. I would rather be sure the problem is solve before the plane goes into the air. Thanks for any advice.