2006 Gen II Prius died while driving, Red Triangle, trac Control and CEL all came on

I think everybody is overlooking the obvious here.

6.7 Volts for a 12 Volt battery is BEYOND dead.
There may be a shorted cell or two.
That might cause the onboard charger (inverter) to stop charging......or drag the voltage WAY down.
Continuing to try and run the car with that battery in it might fry the inverter.

GET A NEW BATTERY. Charge it up then install it.
Only then will you know if you have other problems or not.

 

Yes, this is obvious, was not overlooked, and is why, in post #16, I suggested to the OP that the failed 12V battery should be disconnected. Then the car could be jumpstarted while the Prius 12V battery remains disconnected to see if the car will become READY and can be driven, or not.

 

Sorry.
I meant to say that everybody seems to be overlooking it except YOU !!

 

I'm glad to hear that a new 12V battery was installed and your daughter's Prius is again operational.

It is unclear whether the root cause of her car's failure was running out of fuel; or the 12V battery deciding to develop a shorted cell or two, thus depressing voltage on the 12V bus, at a time when the fuel gauge happened to read two bars.

If the 12V battery had not died, then DTC would have been stored which would reveal the car's problem. For example, if the car had run out of fuel, DTC P3193 would be logged. However, if the battery voltage drops too low, or when the battery is disconnected, all DTC will be erased (except DTC logged by the skid control ECU and SRS ECU.)

To eliminate the possibility of running out of fuel in the future, I would suggest that she consider changing her refueling habits so that she buys gasoline no later than when the fuel gauge shows three bars.

 

as long as the battery fits, that's the important thing. yellow top is not necessarily the best.

 

have you checked the oil level? sounds like metal on metal

 

If the noise persists, besides checking the engine oil:

Remove the spark igniters and spark plugs for inspection if the car has logged a misfire DTC: P030x where x can range from 0 to 4. 0 indicates a random misfire; 1-4 indicates a specific cylinder with a problem. Cylinder 1 is closest to the passenger-side fender. Make sure the electrical wiring harness connectors to the igniters and fuel injectors are locked, not loose.

Smell the fumes from the portable gasoline container used to confirm your daughter added gasoline, not diesel fuel

Remove the engine air filter and hold up to the sunlight. Replace the filter if you cannot see light through the filter. Remove the mass air flow sensor mounted on the air cleaner housing, and clean with MAF sensor spray cleaner. Look at the throttle body interior and throttle plate and if you see dark deposits, scrub them off using throttle body cleaner applied to a clean cloth.

Check the engine coolant level, not only in the overflow tank but also remove the radiator cap and look inside. Need to first remove the large black plastic cover over the radiator, for access.

Check the tightness of the serpentine drive belt. 22 lb force applied by your finger to the center of the longest run of the belt should deflect ~0.5". See if the noise is coming from the engine coolant pump or the idler pulley.

Check the transaxle ATF level, which will require a 24 mm (or 15/16") socket to remove the fill plug. You may need to raise the front of the car for access. The fluid level is determined by being able to feel the fluid with your finger inserted into the fill hole. It should be within 0 - 5 mm from the bottom of the hole when the car is level.

 

The first batch of fuel you put in with the gas can, is that old fuel? Ever had diesel in the gas can?

Either way, at this point I think a full maintenance is in order. If you haven't changed the following, you can do them now. They would be associated to engine performance/power.

Change spark plugs
Clean throttle body and maf sensor
Change Air filter

 

The first thing I would do is clean out the throttle body. Takes 5 minutes. There is no code for a misfire so spark plugs may be ok (but still recommended to change at 120k miles)

 

How many miles on the odometer?

I suggest that you encourage your daughter to fill the fuel tank prior to departing for her trip home and to make sure her cellphone is fully-charged in the event she needs to call you for help along the way.

DTC P3190 offers the following list of suspect items:

Air induction system
Throttle body
Fuel pressure
Engine
Mass Air flow meter
Out of fuel
Engine coolant temperature sensor
Crankshaft position sensor
Camshaft position sensor

ECM