A question about invalid mode and brake fluid flush

Is your mechanic paying you?

 

The car will otherwise react adversely to the "leaks" it thinks it is detecting while you are bleeding the brakes.

 

It's not hard. Two gotchas:

Set parking brake first.

Push brake every time you need to shift to Neutral.

Also, don't accidentally turn a wheel while in invalid mode, that's one way you can get kicked out of the mode, while you're still bleeding brakes.

Turning the car off (when done) is another way.

 

Maybe hook up an appropriate smart charger while you're doing the procedure. I think 4.5 amp max rating is the ceiling for 3rd gen?

With our low usage, I'm all over that: have a CTEK 4.3 hooked up more often than not, just leave it on.

 

Toyota's dealer procedures that involve doing (lengthy task X) while the car is ON often start with attaching a rather stout 12 volt power supply (their "GR8 Battery Diagnostic Station) to the battery terminals. That is, they don't use something limited to the gentle 4.2 amps that are comfortable for charging the battery, but rather that can supply the somewhere-in-the-tens-of-amps being drawn by the car's equipment while it is turned ON. (And be sure to not have any unnecessary large loads turned on, seat heaters, defoggers, HVAC blower, lights, etc.) They especially insist on this for procedures involving reflashing something (where an ill-timed power loss could leave something a brick).



Of course if there is no GR8 handy, a few amps from a battery charger will still be better than nothing. Or even just having a well-charged larger battery to parallel over to the one in the car.

 

Good point.

 

Did you drain coolant via the engine block drain? You might also get more out pulling one of the exhaust heat recovery system coolant hoses. Next time, lol.

 

I've attached the Repair Manual Coolant change instructions. They do mention the engine block drain, but not the exhaust heat recovery.

That said, I'm sure someone here has said they opened the engine block drain, and got a cup at most?

I've only done drains on Hondas in past, this'll be my first time on a Prius, due this fall for me (10 years). I for sure will open the engine block drain at least this first time to see for myself. One reason: with Hondas, I always got a freaking deluge out of the engine block, and there was no nice spigot you could push a tube onto: it went EVERYWHERE.

The engine block drain point is pretty difficult to get to. It's pretty impossible to see without a mirror, and/or the engine cowl pulled off. You can just see it from below, with the engine under panel off, I think. Reaching it is tough too. It's around the back of the engine, about half way up, near the passenger end. There's a small bolt you loosen (may take an allen key), and directly adjacent (below?) there's a spigot you can push a tube onto.

The exhaust heat recovery system is not mentioned in the Repair Manual, as a drain point. But someone here thought to do it, and it seems a good idea: it has engine coolant, so pull off a hose and you'll drain some. Not sure how much, maybe a pint? It's easy to find, roughly where the exhaust starts running horizontal, look for a hose to pull off.