Will the brake fix make it easier to disengage the cruise control?

From what I understand, the answer is no. This firmware upgrade adjusts the sensitivity of the ABS system.

The cruise control and the rear brake lights are controlled by switches on the brake pedal which are not affected by the firmware upgrade.

 

Why do people think a fix designed to correct problem A will also fix (fill in a completely different problem)?

 

Sounds like you need the brake light switch adjusted. The brake light should come on with a light touch of the brakes (and this should switch of the cruise control also) so take it in and have the brake light switch adjusted under warranty.

 

My understanding is that the brake light and cruise control cancel both use the same switch which is operated by the brake pedal under the dashboard. I have looked at the switch and it is adjustable but kind of hard to get at.

 

I guess it varies by car. Although I can't imagine why it would make a difference. The cruise control has to get a signal that the brakes are on. Most of them use the same switch that turns the brake lights on.

On my car it made absolutely no difference at all.

On the other hand, what kind of a driver reacts to a failure of the cruise control to disengage by either doing nothing or continuing light braking? My reaction is to push the brakes harder and lo and behold, the cruise control disengages.

 

The 3rd brake light on the rear of cars? That doesn't come on during regenerative braking?

 

I pull the stalk towards me to turn it off.

This changed from my old behavior of tapping the brakes to alert the car behind me that I was slowing down.

I started turning it off with the stalk when I noticed the cc was not disengaging correctly. I only hit the brakes harder if I'm trying to stop.

 

Other than in an emergency (which includes any time you are surprised and have to slow down quickly) the "correct" way to cancel cruise is to pull the stalk towards you.

In the above "emergency" a firm foot on the brake pedal will cancel cruise. If it doesn't the switch needs to be adjusted, because the brake lamps will also not be working correctly.

 

The owner's manual says there are two ways to cancel the cruise control, pull the stock up or depress the brake pedal. I think both ways should work without problems, and I know of no reason why they wouldn't if the switch that controls the brake light and cruise control cancel is adjusted properly. Apparently quite a few cars, including mine left the factory with this switch adjusted wrong.

If I try to cancel CC with the brake pedal it starts loading the engine down before the CC disengages, this also means I have quite a bit of brake applied before the brake lights come on. If I really mash down on the brakes, no problem, CC cancels and brake light comes on. But if I apply the brakes gently as I usually do I sometimes notice people getting rather close before they realize I am braking.

I have driven to many cars to think pushing the brake pedal this far to cancel the CC or turn on the brake lights is normal. Some earlier CC systems, such as the one on my pickup truck, did not have a cancel switch other than the one on the brake pedal, and the clutch pedal if it were a manual transmission. The only other choice on those vehicles is to turn the CC completely off which means you loose the speed setting, so a lot of us got used to canceling the CC with a light tap of the brake pedal. On all of the other newer or older cars I have driven, including a Corolla loaner and my friends Hybrid Camry, a light tap on the brake pedal is all that's required.

I did take my car in to have the switch adjusted but the service department didn't want to adjust it, they said because the CC cancel and brake lights were on the same switch if they adjusted the CC correctly the brake lights might stay on all the time. Seems to me like it would have fixed both problems. I don't like to argue with them so I'll either go to another dealer or do it myself. In the meantime I'll cancel the CC with the stock which works fine as others have pointed out. But I would like to have the option of doing it either way, and the brake lights really ought to come on sooner.

 

Regardless of what they revolve around, it makes no sense logically because fixing other aspects of the braking system introduces additional complications/bugs that they're not even going to attempt especially for a safety recall and due to the lack of TSBs for the grabby brakes and cruise control issues for existing Gen IIIs if they're indeed fixed in post-January productions.

 

I agree that the brake recall is designed to correct a completely different issue from the CC/brake light problem. There should be no effect unless the reflash caused brakes to be applied at a different point in the pedal travel. If that happens it could make the CC/brake light problem worse or better depending on which way it moves. Not enough people have had the recall accomplished yet to know for sure, my guess is there will be little or no effect, but it is something to check because there could be.

I will note the approximate position of the brake pedal when the brake lights come on before and after the recall just out of curiosity.

 

If the switch is adjusted correctly, or, put another way, is adjusted in one way, then the brake lights will come on when in regen. The third light is no different than the other two brake lights (they are all connected to the brake light line).

Because the Prius brakes are different, and because the pedal moves further than "normal" brake pedals, adjustment of the switch can be different.
Do you want it adjusted so the light comes on in regen (very light braking) or only when you press hard? I suspect the former.

You can see the third lamp come on when it's dark, so there is no reason you can't know if it's adjusted correctly. If it isn't take the car back and stop complaining here!

 

Yep, any time I'm braking (lightly or otherwise) I want the guy behind me to know so he doesn't run up my rear!

 

Sorry this is a bit off topic but I have to ask.

David, are you sure the other two are controlled differently, i.e. the pressure from the brake line? I thought so myself after looking at the wiring diagram (which wasn't to easy to follow without explanation) but the service manager assured me that the pedal switch controlled all three. When I got home from the dealer I found the pedal switch under the dash and was able to turn all three lights on and off by holding the pedal down and pushing it with a screwdriver.

But I know the brake lights are also controlled by something else because we get brake lights when the brakes are applied by the CC or the PCS system?

 

On the Gen II the brake lights are controlled by a switch on the brake pedal assembly. I don't know for sure about the Gen III, but I believe it works the same way.

Obviously you want the brake lights to come on when braking. How the braking force is developed is irrelevant.

B mode is the only exception. Since B mode is analogous to down-shifting, and down-shifting does not light the brake lights, you can make a case that B mode should not light the brake lights.

Tom

 

I got my Prius brake recall fix done today and it absolutely does change the way the brake disengages the cruise control, for the better. I'm no mechanic so I won't pretend I know why but it does make a noticeable difference.