I know that I can discuss this topic with my Toyota service center but I'm interested in what anyone here thinks. I recently had my brakes adjusted and when I got the car back the friction point (the point where braking begins) is really close to the top of the run. It also seems that regenerative braking is less than it used to be. I've also been told by someone in our parking lot that my brake lights aren't always on even though I have my foot on the brake pedal. It seems that they go on only if I apply more pressure to the pedal. Here's the question, how far from the top of the pedal run should it be until braking should begin? Thanks for your input. Tim
Why were the brakes adjusted? With the mimimal brake use in the Prius, I wouldn't think it would be necessary. Have you had the brake light recall done on your 04? After this was done to mine, only a very light touch turns on the stop lights. The answer to your question depends on what speed you are traveling.
<div class='quotetop'>QUOTE(seasalsa @ Mar 9 2007, 07:35 PM) [snapback]403110[/snapback]</div> The brake light recall didn't affect my VIN number. I had the brakes adjusted because the pedal went half-way down in travel to the floor which then triggered hard and sudden braking putting all occupants in hand stands. It seems that the brake pedal has a sensor incorporated to sense speed of pedal application and travel distance so as to activate the hydrolic brakes. When I'm at a stop with the pedal applied, the brake lights are not on unless I give deliberate pressure to the pedal - more than required at a stop. Also, I've noticed that sometimes at a stop the electric motor is activated unless I give more pressure to the pedal.
Tim if your brake lights do not go on with the *slightest* motion of the brake pedal, then the position switch is adjusted incorrectly. Or, you need a new position switch as seasalsa mentioned. Some 2004 Prius have needed that.
Hi TimCarlos I drove a 2004 Prius for over 2 years, now traded for a 2007 Touring Edition. On both Prius, light application of the brakes did not light the stop lights. One thing I noted was that with the MFD on "Energy" with only light application of the brakes, the 'arrows' showed power still flowing from the main battery to the wheels. This is the 'anti-creep' feature simulating the action of a regular automatic transmission. To stop the power flow, I simply applied more brake pedal pressure. A previous response is correct. The brake light switch {located on the upper arm of the brake pedal - under the dash} can be adjusted which controls 'when' the brake lights illuminate. I am unaware of whether that setting also controls when energy flow to the wheels is ceased. ASIDE: Up until a little over a year back, we had an active Prius Meetup Group in the Dallas Metro area. As many as 14 Prius would attend for a Saturday or Sunday luncheon and share experiences. The national organization imposed a fee - $75 for three months - on the "Organizer" who then had to try to collect from attendees or absorb the fee, so he gave it up. No one had stepped up with $75 to re-organize the Prius Meetup Group. It was an interesting sight to see that many Prius lined up in a parking lot.
...So, the brake lights should turn on at the lightest touch to the brake pedal? (I'd think so---they did in my last car, and that slightest touch was also enough to cancel Cruise Control back then.) It seems in my 07 Prius, that the slightest touch doesn't activate the tail lights... nor kill Cruise (though I'd have to test that again, to be sure.) I can be at a dead stop, even on a slight decline, with enough pressure (VERY light--basically the "resting pressure" of my foot's natural, relaxed resting position on the pedal) to hold the car still, yet I will see the battery/energy arrows flowing to the wheels... I apply a little bit more deliberate pressure to stop those arrows (why waste any more battery juice at a dead stop than necessary?) and I *believe* it is only at that level of extra pressure (we're not talking a lot, but more than I'm used to) that my tail lights also come on... Normal?
<div class='quotetop'>QUOTE(ChristoB @ Jul 13 2007, 11:15 AM) [snapback]478102[/snapback]</div> Yes, normal. Tom
yes. There's a very small bit at the top of the pedal travel where the lights won't come on. Then there's another small area where the lights will come on but you're not actually braking. After that, then you're braking (regen or friction) Again, they're very small areas.
I can't speak to the brake function, but I can comment on the light activation adjustment. Brick recently did a great writeup on how to adjust it. I used his instructions to adjust mine, and mine now light with just slight pedal pressure. Of course if the shop screwed it up, you might consider having them fix it.
I hadn't seen Brick's writeup before. Good stuff, although I think there's a small subtlety about brake ECU activation that's easy to miss. Once the system has been activated once via the stop switch [and that's probably via the second set of contacts that goes off to the ECU], it seems like the threshold for starting to fire the solenoids [hearable as a click and some high-pitched whining] is governed by the stroke sensor pot. I've semi-by-mistake pushed the stroke pot arm back a little bit, and had the ECU fire up and start modulating solenoids after I let *go* of it -- i.e. I had given it a new "zero" position just by pushing it a little. It reset itself soon after. Being sort of curious about this, I then arranged to hold the stop switch *in* with a thin flat object and then pushed the pedal, and still heard the ECU start doing its thing. So that told me that the stop switch isn't the trigger for most braking events, it's just to get the brake lights on. . On the other hand, more recently I've been pushing the pedal and jamming an object in between the bracket and the pedal in an effort to maintain brake pressure to the wheels while I try to hunt down an annoying suspension klunk. In that case, the solenoids keep working seemingly indefinitely. Probably because there's actual meaningful pressure at the PMC sensors, i.e. the other inputs to the ECU. . I *hope* I have time to get into all this in detail at Hybridfest.. . _H*
<div class='quotetop'>QUOTE(ChristoB @ Jul 13 2007, 08:15 AM) [snapback]478102[/snapback]</div> My 2007 I notice the same thing. I'm not exactly how hard you need to depress the pedal before the mechanical breaking kicks in. I try to be light on the pedal to use dynamic breaking as much as possible. One time I managed to get all the bars on the battery lit.
