**ComboMeter works 20% of the time. Sometimes the car turns off completely, sometimes not. I have battery switch on 12v to make sure car is turned OFF. This event started with the switch OFF. **Turn switch ON, insert fob, push button and car starts normally, CM is working and I drive away. **Car dies on highway 3 hours later. Red triangle, typical amber lights EXCEPT NO CEL. OK, red triangle, no cel and NO START. Tried several times to restart and goes READY, but as soon as engine tries to start READY goes out. I was able to move the car to convenient spot under battery power. Get trailer, get car and connect Techstream. Techstream show no reason for what happened. See pics. Never mind the date in TS, laptop battery is dead and I never set the time. Engine will try to start, about 1-2 seconds cranking. Ready will illuminate untill push gas pedal far enough to force engine start. Light foot on pedal will drive/reverse on battery. Once engine attempt to start fails, READY goes out. Pulled air filter and TB was a little black, but not terrible. Shot a little carb cleaner in and a shot on MAF. Good 12v and HV batteries, so dont go there. Gas level was 3 bars, my normal level before filling. Pulled rear seat and put 12v directly on fuel pump, 2.8 amp draw and no bad noises, just a nice light humm. With fuel pump running on separate 12v source, I tried to start with the same failure. A good shot of either down the TB did not work.
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.
That is my normal startup procedure. If the battery was overheated, should have thrown a code. The battery fan is clean and does work. The CM was/is working at the moment. I know if the CM was not working there would be NO lights at failure time and car would appear to be simply off and dead coasting to a stop. Once "reset", it can work for several days to a week or so. It will decide to go out a any random time.
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.
Good to know after the car is running again. I suppose after serving well for 12 years, somethings gotta happen, but not ready to give up now.
Possibly, but not in the past. Added 5 gallons of 87 non-ethanol (normal diet) did not change anything.
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.
I realize the reset. It hasnt been an issue in the past still average 47+MPG. But the TB sticking does sound interesting. Odd it would be an issue driving, but certainly starting. I'm still sure the issue remains external to the system and this would fit. After all only need two things for engine to run. Fuel, pump is running, I'm nice person-u-mming it is pushing fuel to the engine. I have not checked spark yet. Since the engine spins so briefly, I'll pull all four coils (leaving plugs in place) and using 4 new plugs, ground all four and watch closely in the dark. I'll pull the TB off and give it a though cleaning as well as MAF. I have to charge the HV now as it is down to 30% and the 12v is pretty tired. I can see there may be two more units marked for furure replacement, but that is not an issue at the moment.
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.
