Car dies on road, No CEL.

My first guess is your hybrid battery is running hot and you might have a hot cell that's about to fail and tech stream didn't catch it because its since cooled and no longer giving bad readings.

Replacing the capacitor on your combo meter so it works 100% of the time will also likely help. Without the combo meter system powered up there's other subsystems that won't work. So my second guess is you might find error codes if you can get combo meter to power up long enough to run techstream again.

One method you can try is hit the power button without your foot on the brake and let the car power up in ACC mode and then put your foot on the brake and power up again. The failing capacitor works more often with this method.

 

Once you get to 2010 Prius and newer you can say the codes would be there... But with Gen1 and Gen2 the system is pretty pathetic and a code can arrive and vanish before you get a chance to catch it.

If I were you, I'd watch Dr. Prius app as you drive and monitor voltage difference and pack temps... I bet your problem shows up during a high amp load with high voltage difference or at peak battery temperature.

 

could the gas gauge be incorrect?

 

It may be that something as simple as you disconnecting the 12v battery is causing your problem. Every time you disconnect the 12v, all 'learned' parameters in the ECUs will reset to factory default. I've had some Gen 2s fail to start after a battery disconnect due to the throttle body. Over years of use, carbon can build up and slightly change where the plate sits. This is compensated for because the ECU 'learns' the new position. This learning is erased when 12v is lost. Spraying some juice down the throat isn't always the solution. Remove the MAF and clean the sensor, it often has dust/debris inside where the heating elements are located. When you look down the throat of the TB, you see an air temperature sensor, not the MAF sensor. The MAF sensor has to be removed from the front side of the body to clean it. I also typically use a toothbrush soaked in TB cleaner to scrub the inside of the TB housing to remove all carbon buildup. This allows the TB plate to fully sit at original position. I've never had a car fail to start following this cleaning.

 

As I understand it, the freeze frame function on an OBD II code reader will look at the last entries for the entire system. So, after a failure, this function (as I understand it) should display all codes recorded for the last system failure. Of course, if the 12 v battery was removed, this data could be lost. So, use this function after the failure but before disconnecting the battery.
I noticed on the display with the DTC's - all are related to the HV hybrid system (there are other lists but this is in common with all codes.) Could the AC compressor be shorting into the system ground? Guessing here but appears some things are seeing high voltage (like the ABS system code.)

 

Throttle body position sensor will throw a specific error code if its sticking... The real value of cleaning TB is to get a fresh start via cleaning and rebooting of computers so you don't have engine computers adjusting the settings to compensate for a dirty TB, but a clean one. Same goes for the Mass Air Flow sensor.

 

There are no codes for the "HV hybrid system". The numbers in the calibration column just inform the software version of the applicable ECU.

The "ABS system code" is about the voltage arriving at the ABS ECU.

The Air Conditioner codes do not implicate the compressor. There is no need to guess; a quick check of the repair manual will show that one code (B1412) is about the ambient temperature sensor. The ambient temperature sensor is installed in the front part of the condenser to detect the ambient temperature and control the heater and air conditioner "AUTO" function.

The other AC code (B1421) is about the solar sensor. If the code was pulled when the car was not in bright sunlight, this code tells you that, and if that was the case, then move on; nothing to see here.

The B1271 tells you what is already known—the combination meter is not working—so there is a Combination Meter ECU Communication Stop

 

About 10 seconds.

Posted via the PriusChat mobile app.

 

Are you sure there's no error codes? You have all kinds of problems and for there to be nothing telling what's wrong tells me your diagnostic tools aren't working. Either the car's ability to log codes or your gears ability to read codes. I mean there's an error code for when the engine won't start, an error code for when the engine has low power and so many others. If I were you I'd diagnose why you can't get error codes before you worry about why the car won't run. Either your 12v is malfunctioning or one of the ECUs.

 

Not getting any codes (but power to the OBDII) could be the reader as just posted or maybe the interface is compromised - obviously the fuse is good or the ODBII reader wouldn't power on.
My earlier post was made since I wondered that if the AC compressor was causing some HV to leak to the frame, the ground connections would be compromise. That, I wondered, might be the issue for those other items on your list. The car should then prevent starting if it thinks the HV system is compromised.
Yes, just guessing but your issue is a difficult one.