Symptoms of a failing ECU typically result in an intermittent issue, which gradually gets worse over time, and can eventually be a hard fault. This is commonly due to wire bond failure inside the ECU, and can result in the following misbehaving...
No crank
Misfire
Throttle position sensor
Mass Airflow meter
Oxygen sensor
No Comunication
Fuel gauge error
Please note, that the type of construction inside this ECU is extremely fragile. And a small percentage of ECUs may suffer from other issues after this repair process.