I got this message in my 2019 rav4. Car would not start. Tried new battery, didn’t fix it, had check engine codes ran, nothing popped up . Towed to dealership. Dealership installed new ecm module saying the old ecm just went dead… here are their words diagnosing:
Ive replaced ecu’s for funky stuff on tacos, camrys, and tundras. Wouldnt be surprised this was your issue.
If your alternator was good, battery was good, and the rack itself is good, there isnt much else to look for besides the ecu.