Prius (Gen 3) :: Lunging While Braking With Weak Traction
May 22, 2013
As in lunge. I first noticed this about two months ago (I bought the car three months ago) when I was braking on straight, level ground, but it was raining and I was crossing railroad tracks while I was braking. Fortunately, no one was in front of me. The sensation wasn't merely a loss of braking traction (sliding), this felt like a momentary, power mode/full throttle thrust. Straight forward. At the time, I was clearly caught off guard, but the effect/sensation was quite momentary, almost as if someone had mildly rear-ended me.
Braking after that moment was normal. The effect didn't replicate itself again until recently when I was braking for a stoplight on a sh-tty concrete road where the sections have a slight tilt to them. This is exaggerated of course, but the sections are like this: ///////, meaning there is a 1/4 to 1" dropoff from one section to the next. there is one particularly pronounced dropoff close to the stoplight. The effect happened again and it is reproducible. Again, it is not merely the sensation of taking your foot off the brake, but one of a momentary punch of acceleration. No appreciable sound of higher engine revs.
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I don't see any mention of the role of the transaxle differential. Others have correctly pointed out that regenerative braking acts only on the front wheels, but it also important to note that the regenerative braking torque is transmitted from the transaxle to the wheels via differential gears.
Thus when braking traction is lost on one front wheel (due to a wet manhole cover, bump or whatever), braking torque is also lost on the other front wheel. The effect is a noticeable instant of "no braking" and takeover by the ABS. Or perhaps the driver takes over by pressing the brake pedal further and activating the hydraulic brakes (this should happen instinctively, and quickly since the driver’s foot is already on the brake pedal).
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I slammed on my brakes the other day because a car pulled out in front of me. When i let off the brakes i noticed the car did not move for a good 1-2 seconds and a traction control light was flashing. I didn't think much of it until i was sitting at a light and decided to see what happens if i press my brake pedals in hard again... the traction light turns on again and the car doesn't move when brakes are disengaged for a few seconds. Is this normal? It feels like my hill assist on the BMW. Why the traction light turns on? My car is a 2010 Prius III with 5k miles.
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Tonight I needed to stop at a red light. The distance to the light was on the short side, so I braked somewhat firmly - but not hard like a panic stop. The road was dry but somewhat bumpy (I think it had some patches across it from some digging that'd been going on.) But it wasn't so bumpy that you wouldn't just drive normally on it. When I braked, the car kept on going. I saw the traction control light come on, and eventually the car stopped at the light. But if there'd been another car ahead of me, this might not have ended well.
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My truck is a 2004 F350 6.0 as with most of the ford diesels from this era it has hydro boot brakes.
Under normal braking the truck felt fine and the brakes behaved as they always have. However if you where to depress the brakes hard, as if making an emergency stop, the brakes would not lock up in the way they did when I bought the truck two years and 80,000km ago. The problem was slow to appear and at first I blamed it on the larger tiers I was running (stock 2012 F350 wheels and tires (yes the offset is wrong)) but after switching back to my stock wheels for the winter I knew that something was not right. It was something I could live with, it did not make the tuck unsafe it was just that it did not stop as well as I knew it could and this avowed me. I replaced the front and rear calipers and when that had no effect I swapped out the master cylinder this still made little difference.
I drove the company truck all of last month (2008 GMC 2500 Duramax) and when I got back in mine I realised that I had to chase down the problem. I did a lot of reading online and after thoroughly flushing and bleeding my brake system I narrowed my problem down to either the hydro booster or the power steering pump. The plan we came up with for diagnosing was:
1. Thoroughly inspect for PS/Hydro boost and brake fluid leaks following the procedure found here Hydro-Boost Power Assist Systems: Operation Diagnosis and Repair
1a. Consider bleeding the brakes as a bit of trapped air would cause your symptoms.
1.b Consider flushing the PS system. Some suggest this works with tough steering.
2. Have a shop check the PS pressure is within spec. (assuming this is cheaper than buying the tool or just replacing the pump) If it is low, replace the PS pump.
3. If PS pump is fine, or is replaced and the problem is still there, consider replacing the Hydro booster.
It is not super complete but it was a place to start. We checked for leaks and found nothing. The pedal would not sink under braking but would say firm meaning the brake system was free of leaks.
I began a rudimentary test of power steering pump. With the truck in the drive way I could easily turn the steering wheel however, applying the breaks about half way would make turning the wheel imposable. This led me to believe the power steering pump was starting to go. The next step would be to have the pump tested using a power steering pressure gage or take the truck to a shop to have it tested. I found the pressure gage to be more expensive then the new pump so went that way. With 350,000km on the truck I figured it was not a bad thing to do even if it turned out to not be the cause of the problem.
It is a bit tricky to get the power steering pump out but after pulling the radiator line under the truck I could drop the pump out the bottom. The new pump went back in the same way and after a full flush and bleed of the system it was time for a test. What a difference! The truck stops like the day I got it. If your symptoms are like mine I would recommend you check the power steering pump. If it is the problem it is a lot cheaper then replacing a master cylinder or calipers.
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I just got my car back from discount tire. Every time I accelerate above about 45 mph the traction light goes off Also, There is a shimmy in the brake pedal under braking.
NOW: there is ONE tire that is SMALLER than the rest that they put on or something. It is a different tire, same company, but obviously a bit smaller. Now, they told me it would be fine, despite my better judgement that It would preform weird as well as look slightly gimp. the tire went from driver rear to passenger front, and I'm willing to bet that is the cause of both problems. What should I do?
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My parents have a 2010 Hyundai Sonata. About a month ago my mom noticed that when she starts to brake, the car stops fine but then it stops again almost, with a loud thunk. The best way to describe it is that you press down the brake, the car stops, then a few seconds later the car feels like it is lunging forward and stopping again with a sudden thump. (Although I don't think it really actually moves at all).
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I have a 2011 F250 Lariat, 6.2L V8. The past couple months i have noticed truck jerking/lunging during acceleration in the mornings usually between leaving the house and getting on the highway. Over the last 2 weeks the problem has progressed and seems to last longer. I have tried fuel injector cleaner with no success. This morning was the worst so far and after all this time i finally saw the maintenance "wrench" pop up on the on dash.
This was good news to me hoping that a local shop could read the code. However, when i dropped off my daughter and started back up the "wrench" went away. After warming up the problem seems to go away. This morning was so severe i lost speed and felt like the engine was going to stall.
I feel like this is related to the fuel system (injectors/pump/filter) but also haven't changed the spark plugs yet. My truck has 72,000 miles and otherwise is in good shape. How I should move forward?
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Just bought a 2010 Hertz GenIII w/44,000mi. Wife had trouble starting it twice with weird messages like place car on flat surface to orange triangle. I hear it may be a weak battery???
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I need to troubleshoot a problem with the ABS & Traction control lights on a 2006 Mountaineer Premium with 126,000 miles. During the year that I have owned the vehicle this problem has occurred every time it is driven on a long trip. The previous owner never drove on longer trips so has no experience with this problem.
When you drive the vehicle around town and on shorter trips (less than an hour) there are no indications of problems. The ABS and Traction control lights come on as part of the start-up check cycle and go off. The ABS and Traction control work in low traction conditions and the lights function correctly when either one is activated.
The unusual behavior occurs on trips longer than an hour. Typically after about 1 1/2 hours at highway speed both the ABS and Traction control lights come on as well as the Wrench symbol in the message panel. It you hit "Reset" the Wrench symbol goes away but the ABS and Traction control lights stay on. The brakes work normally. I do not know if the ABS and Traction Control will work. I have never been in a low traction condition when the lights are on.
Both lights stay on until you stop the vehicle and turn off the ignition. When you restart the vehicle the ABS light is on but not the Traction Control light. When you start to drive the vehicle the ABS light goes out immediately.
After about 1/2 hour of driving both lights come on and the Wrench symbol displays in the message panel. Whenever you stop the vehicle and restart during the trip the cycle repeats. The day after you finish the long trip everything is normal for driving around town and on short trips.
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After going through the Prius v manual, I just realized that there is no way to turn off traction control. Now, 99.9 % of the time, traction control is a good thing. But sometimes, it is useful to be able to turn it off.
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Had the ABS light and traction control light come on and I wasn't getting regen when I braked anymore (which is a weird feeling). So of course I pulled over and tried restarting but the same thing happened about 10 seconds after I took off.
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This is my first year driving my prius during a hot season, and for past 3 weeks my mpg has dropped from 49 to 41-43 mpg, and the reason is my traction battery keeps getting HOT! I can hear the battery cooling fan turning on constantly at max when i reach 20 mph, my car doesn't want to start in EV mode the engine just kicks in no matter how light you press the throttle, the EV motor is not assisting with the engine, the infamous slow rpm drop keep occurring and I when to touch the traction battery case and it its HOT, Ive open up the case to check for any dust on the fan and ducts but so far its spotless. I really wished they place an AC vent for the battery because the back passenger area with full A/C doesn't t get as cold as the front dose which doesn't cool off the battery.
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On my 86' 740 the cranking has been kinda lengthy and a bit weak as if the battery is going bad. I finally had an episode where the cranking and the start was stranding me. After three attempts and keeping the throttle wide opened it started. What is now strange is the crank is strong and faster as if something broke loose or got reset.
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Recently installed 35w Canbus Slim Ballast 6000k HIDs into my 2014.5 Camry SE projector headlights (black bezel). For some reason it seems like the Halogens lit up better. I get very poor lighting, and when I drive on the highway at night it barely lights up the signs. I don't know if I need to adjust the angle of the projector because the beams seem kind of low or if I need to upgrade the ballast to a 55w. Also not sure if the housing or the stock wiring can handle the 55w without causing damage.
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So I installed a new f23 turbo about a month ago now. Doug over at frankenturbo has been working with me to tune my car, but we have figured there is a possible boost leak. I've checked all my hoses and can not find any bad connections. My current setup is a forge twintercooler, cts intake, and a ecs boost gauge. I've been over everything 3 times now and can not see where anything could be leaking. I can tell you when in low rpm's the power and boost is very weak. Doug suggested to turn the wastegate up and we did. Still no result for the low rpm to build boost. I'm at a loss.
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My a/c is weak and the compressor clutch is on all the time. What causes that?
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As you can glean from Discussion Title, I have a 97 Honda Accord that has been weak in producing cold air with the a/c on since we bought it three years ago. The car has been the "third car" for kids to drive so not a big deal. Now that one of the "kids" is commuting this summer to an internship, the hot car is a problem. I drove the car this morning as I just drive to the train, and noticed mist coming out of the dashboard vents when the a/c was on. The mist stopped when the a/c was turned off.
Does this misting mean we have an evaporator core leak, or other problem? It certainly doesn't seem like just a freon boost is needed. If the evaporator core needs to be replaced, how bad a job is that? I replaced one in a '72 Plymouth Duster once and didn't seem so bad.
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I don't own a Prius, but my parents own two identical 2002 models (each with 120k miles).
My mother's car wasn't driven for nearly a month (hip replacement), and when they tried to start it last week, the ready light would blink 3 times - but no cranking.
After taking it to the dealer, they were quoted $4600 to replace the traction battery and ECU. We did the mandatory research on rebuilt batteries, but with only a vague diagnosis from the dealer, we were not convinced that this was the (only) problem.
So, my brother and I decided to swap the ECU, then the battery from my father's working Prius to my mother's - thereby proving the issue. Upon removing the 'dead' battery from mother's car, I decided to open the module, and check each battery. We measured anywhere from 3.0 to 6.4V on the individual cells - and 7.0V to 11V on the paired cells. It was clear that the batteries had discharged unevenly. The total charge remaining was about 151V - still above the 40% SOC minimum I'd read about.
We then bought 5 x 10A chargers from Walmart, and connected each to a pair of modules. Set the charge to rapid (10A) and waited 30 minutes (or until the charger indicated full). After 2 hours, all 19 pair were charged fully - with each reporting 15.7V +/- 0.5V. The total power was about 295V.
We reassembled the battery, re-installed it, and the car started immediately. We let it sit running, until it cycled off on its own. About 5 min later, the ICE fired again to charge the 12V battery - but it threw a P3006 error code. It showed a PS + MAIN + battery icon on the MFD. Using an OBDII scan tool, we cleared the error, and drove the car for a few miles. The error code did not return during that drive - but did one more time after letting it cycle off/on automatically. After clearing the code a second time, it never repeated again.
My assumption is that the 300V HV charge was above the 80% SOC and it didn't like that. But after a few cranking cycles, and the tendency for the battery to discharge back to it's rated output, the error no longer repeated.
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Over the last few weeks I have noted the following when I first start the car in the morning : I turn on the car, and turn on the A/C (this is Arkansas, remember, and the sun has already heated the car up pretty good). The Traction Battery is usually at 6 bar+/-
Over the next few minutes (driving uphill, maybe stopping for a minute to put trash in our trash cans, A/C on all the time), the Traction Battery goes down to 2 or 3 bars quickly. Then over the next few minutes it pretty quickly comes back up as I start driving faster (40-45) on a main road.
I am guessing this is happening now because of my A/C use. But I don't remember this happening so much in previous summers, which were at least as hot.
BTW, I start driving as quickly as possible after turning the car on (little or no warm up). So maybe some of this has to do with the car using battery energy while the engine is warming itself. But again, I never noticed this before.
Is it possible that a cell or something in the battery is going bad? Or is it just completely normal and I just never noticed it before and I'm having Traction Battery Paranoia?
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I am a new owner of a 2007 Prius and as the snow will soon be here, will driving in B mode rather than D provide greater traction?
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