Grinding noise, after “battery low voltage” warning. When engine started.

Actually - there is no starter. The MG1&MG2 work to do the driving, starting, generating etc.

 

I may be wrong, but I thought that the 12V battery was only used for the electronic systems: the HV battery is used to start the engine.

 

That’s it exactly: if the car is off, or in ACCESSORY or (Ignition) ON mode—in other words, in any condition but READY mode—the system main relays at the HV battery are open, so the DC-DC converter has no power source from which to energize the 12-volt bus or charge the auxiliary (12-volt) battery.

The Owner’s Manual (PDF, always warm at Toyota.com) explains the modes on page 227.

I’m not sure what this might have been. Are there any other signs of trouble?

 

Just as an aside - I had a flat 12v battery, I think over 12 months ago (operator error, I'd left the car open, and some lights on). But I left it for an hour or 2 to revive, and it worked fine again - and has ever since. BUT - there was no grinding noise, so sorry, no idea.

 

I think he's saying the car didn't go into ready mode, "just turned all the dash lights n stuff on for the split second to try to start it..." not enough power in the 12v to energize the HV battery relays.

Brandon, I think it does have 12v protection, ISTR reading somewhere that, in acc mode, the car switches itself off after a certain time (20 or 30 minutes was it ?) to prevent the 12v dropping too low to go into ready mode. So it seems you may have a weak 12v. Depending on use, i.e. leaving it in acc mode often or infrequent or short journeys, it may be worth may be worth charging the battery up now and again on a trickle charger/conditioner, if none of that applies then the 12v probably needs replacing. I do with mine every 5-6 weeks because I do less than 3K miles a year and mainly short runs.
I've no idea what the grinding could be, are you sure it's a grinding noise and not a relay buzzing due to low voltage.

 

i hope the 'grinding noise' wasn't gen3 cold start knock

 

There is a one way safety clutch between the engine and tranny. Maybe it spun a little

 

My experience (in the Last Post) is that not everything turns off. I know my taillights were on while the car was off, and they didn't turn off. I was made aware when a neighbour knocked on the door to tell me my lights were on. I don't recall which others were.

I thought it was odd - as my KIA 10 yrs earlier did turn everything off (at least I think it did - it definitely turned the interior light off in 20 mins - I tested it!!).

 

What I really meant to say was that it kicks you out of ACC mode after the allocated time.
The interior lights do turn off after 30 minutes if you leave the switch in the on position with the car totally off.
The tail lights and front parking lights will stay on indefinitely if left on when the car is off so you can park in areas where parking lights are required.

 

Ahh - that's probably what I did. I think it was off. I must try again.

 

Drain your HV battery till the ice kicks in to recharge. Accelerate gradually from stop. Check if you hear the same grinding sound as the car speeds up.

I had the same issue on a second hand I was testing the other day. Wasn't sure whether it's the CVT or engine as it's only replicable when HV battery is drained and ice had to do most of the work between 8-25km/HR


Posted via the PriusChat mobile app.

 

It’s a bit late for me to join in, but I’ll give you my 2 cents. All internal combustion engines have fly wheels and I believe this applies to all Prii. I have never had my car cleaned in a car wash, so I know little, but I presume they want you to put the car in N, right? Also you should keep the car in ready so you have no problems with
Water shorts Also the HV charging source is able to keep the 12V tapped off to its normal 14-15 Volts. You may also have loaded down the 12V source thru overuse, misuse. Pay attention to the charge state of the 12V battery. Never run the radio while parked unless the car is in READY, or any other accessory, built in or
Added! There is a 12 V check that you can use on the car, you’ll have to ask other members.
As for that incredible grinding noise, you should have gotten a worker to verify and called up the owner, then,
Until the issue as clarified. Did you ever find the source of the problem?