Hot Coolant Transfer Pump issues, part 2

a little one?? :blink: as in children? eeeek, no

that's the structure of carbachol, one of the drugs i treat my cells with. i got bored this afternoon.

 

sorry! it looked like and X and a Y with a little one in the middle. When you get bored at work it can bring a lot of thoughts to other people! Like I said, sorry!

 

haha! no need to apologize! we got a good laugh out of that one :lol:

the whole kids issue is kinda up in the air at the moment...

[edit] now if you had told me i looked pregnant we'd have an issue :lol:

 

I'm 58 years old, a long time ago I learned to never say that, unless it's totally obvious

 

Back to the low HV battery.
You can't deplete the HV battery in any mode but READY, as it is not connected in any mode but READY.
In READY, if there is an idle load to the HV battery, which could only be a 12V accessory or the AC compressor, the ICE will be started to recharge it, unless you are in neutral, in which case the car will be turned off when the SOC gets too low, but not too low to power back up and start ICE to recharge it.

To clarify on the coolant storage. The coolant is exchanged from/to the storage tank, to/from the ICE. The ICE is never normally depleted of coolant.

 

the battery won't drop to 2 bars, Tideland Prius. the system main relay is off in any mode but ready, as DanMan said. so the HV battery can't be tapped at all, it's cut off from the system. all that would happen is that your 12V would drain and the car should just shut off.

 

I just said, the HV battery is disconnected when you are in Ig-On, so you will never get down to two bars in that mode.

In READY, the car will shut off if the SOC gets down to no bars. That is not possible in Ig-On since the HV battery is not connected to the inverter and therefore cannot be drained.

READY and Ig-On are not the same mode. Ig-On is obtained by pressing the power button twice without pressing the brake. READY can only be obtained by pressing the power button while pressing the brake.

Some have reported seeing the SOC go down even in Ig-On mode. I believe what is happening here, is that the cabin temp, and thus the battery temp changes, and the battery ECU reports the SOC relative to the battery temp. A hotter battery can hold more energy, so the relative SOC display will drop for the same amount of stored energy, much like the relative humidity in the air drops as the air temperature rises, since the air can hold more moisture.

But rest assured, the system main relays are completely open in off, ACC and Ig-On modes. That's why you can't get any cooling in any of those modes, but you can get the fan in Ig-On.

 

I don't know what your scenario was, but I was calculating a drop in SOC while in Ig-On as the battery warms up.

Lets say the battery has 50K coulombs, where a coulomb is a unit of charge. I may have my range way off base, but we'll use this as an example.
Now, at 70 degrees, the battery will show full at 100K coulombs, therefore would show 50% full. But at 80 degrees, it can hold 150K coulombs, therefore would only show 33% full even though it has the same amount of absolute charge: 50K coulombs.

 

You shouldn't see much change in Ig-On, especially in bar 6 which has a wider range.

 

My '04 Prius with 5k miles on it no longer has the normal coolant pump sound at shutdown or startup it has no pump sound at all. It've been cold here in Chicagoland and I am not sure exactly when the pump sound vanished.
A call to the dealer said it's normal for the pump to not pump in cold weather. A call to Toyota Customer Assistance gave me a similar (not confident with the rep though) response and said if the car isn't overheating (how would I tell) the absence of pump sound at startup and shutdown is normal.
Somehow I'd like to believe them both but don't have a warm fuzzie feeling.
Is the total absense of any coolant pump sound at shutdown or startup in colder weather considered normal?
From my total milage it should be noted I make mostly short trips (<5 miles) on a daily basis.
Thanks,
J

 

if the coolant isn't hot enough, the pump won't run.

5 miles in cold weather could be too little driving. have they tested the pump itself to see if it runs when commanded? they can do that with the scan tool.

it's probably okay.

 

No, I have not brought the car in. I will have it checked next time it's in for maintenance.

 

just go for a drive where the ICE gets hot IE: probably about 15 mile or so on urban/surban streets. When the car is pumping out from the heat vents and it's been doing that for at least 5 minutes find yourself a parking lot pull over open the door and turn the car off get out and listen at the Left front wheel. You should then hear the pump cycle. Save a trip to the dealer. But I have to agree that <5 miles a day probably has flushed all the hot coolant from the thermous.

 

time to use Regency in Burnaby at least the techs there have gotten used to working on Prius. They do all the major dissambley from the body shop and are pretty skilled in the ways of the Prius. But Darren at Langley Toyota Town is supposed to be the hot tech on Prius. sounds like your guy's need to go back to Toyota University in Richmond.