Very helpful guidance and schematics, Joe! Thank you!! We finally got the car to run, but it still fails sporadically. It's very weird. If the battery is disconnected and then reconnected, the car is dead. it won't do anything except blink the "red car with a key" symbol and the emergency blinker blinks only inside the car. What I discovered, through process of elimination, is that if the top connector (of the 3 connectors) on the ECU behind the battery is disconnected, then reconnected while the battery is connected, the car works fine the first time, and sometimes it keeps working for a few trips. Eventually, it begins to give the same symptom of the icon blinking, but will sometimes suddenly flash the green key symbol and the car fires up. If that doesn't happen, unplugging the top connector on the ECU does the trick.
I cleaned up all the grounds, including all the metal brackets for the ECU. The alternator is new, although it wasn't actually bad.
So, it seems it's either an ECU issue, or something connected to the top connector on the ECU that resets when the ECU is disconnected from it.
My teenage son drives the car, so I need it to be more dependable. Any other suggestions are greatly appreciated! Thanks again for your help!!
Mike
Apr 21, 2021 at 2:24 PM