How to access Gen 4 Prius Prime Maintenance Mode

2019 PRIUS PRIME (GEN 4) MAINTENANCE MODE.
THIS MODE STARTS THE GASOLINE ENGINE AND ALLOWS IT TO RUN WHEN NOT BEING ACTUALLY DRIVEN, FOR PURPOSES OF EMISSIONS TESTING, CHECKING FOR OIL LEAKS, OR JUST TO WARM UP THE ENGINE FOR AN OIL CHANGE WHEN YOU DON'T WANT TO DRIVE THE CAR AROUND.

WARNING! INTERNAL COMBUSTION ENGINES PRODUCE TOXIC CARBON MONOXIDE WHEN RUNNING. DO NOT PLACE A TOYOTA INTO MAINTENANCE MODE IN ANY ENCLOSED SPACE SUCH AS A GARAGE.

NOTE: DO THESE STEPS QUICKLY. I THINK STEPS 2-8 HAVE TO BE COMPLETED WITHIN A CERTAIN TIME LIMIT (15~20 SECONDS?).

1. Engage the parking brake if it isn't already.

2. Press "START" button Twice to go into "IGNITION mode"
(DON'T PRESS THE BRAKE PEDAL HERE! DOING SO WOULD PUT YOU IN "READY" MODE, WHICH ISN'T WHAT YOU WANT).

3. Press Accelerator pedal through it's full range (to the floor) Twice and release.

4. While holding the Brake pedal down, push shifter lever to "N" and release.

5. Press Accelerator pedal through it's full range (to the floor) Twice and release.

6. While holding the Brake pedal down, push the "PARK" button and release.

7. Press Accelerator pedal through it's full range (to the floor) Twice and release.

8. While holding the Brake pedal down, push "START" button once. The ICE should start up and idle.

9. To end the test, press "START" button once to shut the car down and turn off the electronics.

THIS HAS BEEN TESTED ON MY 2019 PRIUS PRIME AND IT DOES WORK. IT SHOULD ALSO WORK ON THE REGULAR PRIUS AND THE COROLLA HYBRID, AND IT MIGHT WORK ON OTHER TOYOTA HYBRIDS SUCH AS THE CAMRY, RAV4, SIENNA, AND HIGHLANDER, IF THEY ARE GEN 4 (2018-2020).

 

Yes, Charge mode would work, but as you said, only if the traction battery is depleted below 80%. I wonder if you really need to warm up these engines at all for an oil change, if the ambient temperature is above 68°F ? 0W16 oil is so thin that it flows almost as fast cold as it does at 200°F. BTW, I found a 3-pack of 5 quart jugs of Valvoline 0W16 on Amazon for $70. That's $23.33 per oil change, or $4.66/quart. I've not found any other name brand 0W16 for less.