Does anyone know how to access the diagnostic mode/menu on a 5th generation Prius? I've scoured the internet and have not been able to find out how to do it. I was able to on my older Prius, and it was a very useful feature.
If no one jumps in who has looked it up already, you could become the first: Toyota Service Information and Where To Find It | PriusChat
Copying from a previous post: Ensure that the vehicle is stopped. Turn the ignition switch to ON. Turn off the audio of the radio and display receiver assembly. Turn off the screen from the settings screen. Perform the "Flick from left to right" operation five times on the multi-display shown in the figure. [Figure just shows a long swipe] Tip: Performing flick operations may cause messages, etc. to appear on the screen, but disregard these and continue performing the flick operations. Flick the multi-display 5 times from right to left as shown in the illustration. Tip: Make sure to complete the operation within 15 seconds of performing the initial flick from left to right. When diagnosis starts, the service menu screen is displayed. Tip: If diagnosis does not start due to a failed operation, turn the display on then off and perform the procedure from the start. (Only turning the audio of the radio and display receiver assembly from off to on is not a valid method) Haven't tried it yet myself though.
I can confirm it works. But it's really just a service screen for the infotainment unit and the cameras/mics. It gives you nearly no info about the mechanical or electrical functions of the rest of the car.
And that's the same as previous iterations, isn't it, as OP asked for? Gives a few bits of basic info like battery voltage, at least.
Thanks! It works like a charm. Easier to access than previous generations. Although it gives little information about the mechanical or electrical functions of the car, it does provide a convenient way to check the voltage of the auxiliary battery.
Yeah, but the car has to be in Ready to run the diagnostic mode. Will that help much for these battery issues we're seeing? I'm thinking you really need to see the battery voltage when the car is off and the 12V is not being boosted in any way by the ICE or HV. But maybe I'm wrong and monitoring the 12V while the car is in Ready would be useful. I've got the HEV and haven't had any issues so I've got no personal experience.