If you can't clear this error message from the I/P display, I think that warrants another trip to your dealer. Is it even driveable at this point???
I had the recall/update several months ago and have not had any re-occurence of this problem. However, it did not even before I had the update. The last time was well over a year ago. I did have my gateway computer replaced under warranty about two years ago, right after the first time it acted up. As I recall it happened a total of 3 times all together over the 3+ year history of the car. Each time it recovered all on its own and the "Check EV . . . " message went away right after each incident happened.
The best way to describe this problem, is something can cause random "glitchiness" of the digital electronics in the car. Who knows why or how often??? Replacing the Gateway ECM is no guarantee the problem will be resolved. The real problem is that Tesla/Toyota has no idea what to do about it and any and all owner reported problems with the 2012-2014 RAV4EVs. These cars are probably just about the LOWEST POSSIBLE PRIORITY for them to work on, because future sales will be non-existent, and they just don't care about existing customers who still own these "compliance" cars.
I have just learned to live with this kind of BS and still manage to enjoy driving the car nevertheless! I don't use for anything for around town errands, so that I minimize risking a complete break down away from home. I did have a complete breakdown ONCE about a year ago, but it was something going haywire with the DC/DC charger for the regular 12V battery. I had to have it towed to the dealer under warranty because it was totally undriveable after that one happened. They replaced the 12V battery and the problem went away. My conclusion? The 12V batteries in these cars - even new - will not last much more than about 2 years before they will croak, i.e. premature EOL failure, and I believe some of the Model S Tesla 12V batteries will do exactly the same, so Tesla recommends their replacement every 18 months to prevent bricking those cars. I believe RAV4EVs inherited the same issue.
