shutdown sequence noise - newbie question

The fuel economy drop is to be expected. Any car's FE drops in cold weather. The effect is exaggerated somewhat in the Prius because of its unique warmup sequence.

Some of us use an engine block heater and/or block the front grille to improve winter FE. There are several threads on each; a good search should tell you all you need to know.

The noise you're hearing may be the coolant heat storage pump. If your car has less than 60K miles, it may qualify for replacement under this TSB.

 

Hello,

This thread (from the Gen 2 part of the forum) is almost 10 years old, but I thought I would resurrect it.

This is my first fall/winter owning my 2011 Prius (Gen 3).

The days are getting cooler, and I am also noticing an unexpected grinding (?) noise when I shut off the system by pressing the "start" button. The sound does NOT resemble a pump, but I cannot be sure, because it is very brief. However, if I am pressing the regular brake pedal (NOT the parking brake pedal) when I press the "start" button the sound is NOT heard.

Here is my shut down sequence: (to be clear, I use the words press and depress to mean the same)

1) press (and hold) regular brake pedal
2) put car into neutral
3) press parking brake pedal (the leftmost pedal in USA cars)
4) release regular parking brake pedal (see below for explanation)
5) press park button
6) press (and hold) regular brake pedal
7) press start button to shut down system

I include steps #3 and #4, because this allows the car to roll back-forward until it is stabilized by the brake, and NOT the "transmission". This combination was necessary on my parent's second car, a Dodge van with a V8 engine and an automatic transmission. If the van was placed in park BEFORE the parking brake was set, then the van could roll back or forward one or two inches. When the transmission would be shifted out of park to drive/reverse a very unsettling bang would be heard and felt.

During the summer step I did NOT include step #6, and the shut down was silent.

But now, with the colder weather I hear the sound if I omit step #6.

Any thoughts about the cause of the sound? I am happy to continue adding step #6, but if the sounds indicates there may be a small problem then I might want to get it fixed before it turns into a more expensive problem.

Thanks for your thoughts!

 

might be the brake pump, can you post a recording?

 

Hi bisco,

Thanks for the response. Four follow up questions:

1) If it is the "brake pump" is a sound normal when the temperature drops?

2) If the sound is related to the "brake pump" is it a serious problem (eg. should I drive straight to a garage)?

3) If it is not a serious problem will my work around prevent the problem from getting worse?

4) I know how to attach photos, but I have never tried to attach, or download, sound files from this forum. What is preferred mp3 or wav?

Thanks for your interest.

 

There is no real benefit in resurrecting an old Gen 2 thread for a Gen 3 problem, especially where you are not referencing any of the previous info.

Maybe start a new thread in the Gen 3 forums, where they have more knowledge and experience of that generation.

As far as your sequence, you can probably cut that back to:

1) press (and hold) the brake pedal
2) press parking brake pedal (the leftmost pedal in USA cars)
3) release the brake pedal (see below for explanation)
4) press the Power button to shut down the system.

The P button will automatically engage as part of the shutdown process.

I don't believe your step #6 has any bearing on the noise, but, then again, I don't know anything about the Gen 3.

 

Thanks for the suggestion @dolj. I will repost to the Gen 3 forum.

I appreciate the idea to shorten the sequence.

However, I am confuse that you do not suggest shifting out of D (or R). If I release the brake pedal when the car is still in D (or R) I assume the car will start to try to roll forward or backward (against the parking brake). If this is true then there is no opportunity for the car to "roll back", engaging the parking brake, before the transmission is changed to "park".

Perhaps I am missing something, or did not explain something well in my post?

Thanks to all.

 

most people just use their phone to record sound with video from the closest place to the sound.

the brake pump noise is the buzzing you hear when you open the drivers door to get in.

anytime the pressure is low, stepping on the brake pedal activates it.

my parking sequence:

1) step on brake
2) apply e brake
3) release brake slowly to make sure e brake is holding securely while in d or r
4) press park
5) press power

 

Well, that got me thinking, and what I usually do if I'm pulling up to exit the car immediately is:

1) Press (and hold) the brake pedal
2) Press parking brake pedal (the leftmost pedal in USA cars and, in fact, all Prius)
2b) I may or may not shift to N here.
3) Press the Power button to shut down the system.

I would probably only additionally put it in neutral if I was staying in the car, and then depending on the length of time, may not even switch it off.

The aspect of "rollback" should be a non-issue if the (foot-operated) park brake is applied with the right level of force.

In all honesty, I can't even tell you with any certainty whether I actually shift to neutral as part of my sequence or not, but it certainly wouldn't hurt to do it, and I will not tell you not to do it.