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Discussion Starter · #1 ·
I picked up my car one day after having Toyota change the oil with the 0W20 that I read about on this site. It seemed to be running and riding wierd. It didn't have its normal glide feeling, and it felt like I had to press the gas pedal harder. I could take my foot off the gas, and I could feel like something was stopping me. I even stopped to check the pressure in my tires, because it felt like something was definitly causing a drag. I also noticed that my battery was 'high in the green' which I almost never see when I'm driving. I wrote it all off as paranoia, but for the next 3 tanks of gas, all I could muster was 42 MPG, and I normally average 48. Then one day I was driving along and hit a bump in the road on the passenger side of the car only, which usually fires the VSC, and the VSC light came on. After that the ride returned to normal and my next tank was 48 MPG. Everything was fine for about a week, when I found a freak iced road, and the VSC kicked in again. Now the drag is back and my mileage has went back down, and it feels like I have to push it harder again, and the battery charge is staying 'high in the green' again.

Has anyone else experienced problem with this? Ready any TSB's about this?


2006 Prius Package #6, 10,000 miles
 

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This may be a stupid question but what's a VSC? Either we need to have a standing set of Prius acronyms or we ask that posters expand the acronym on first mention and then use the acronym after that.

My guess is that VSC stands for Vehicle Stability Control (but I still don't know what that is). The other acronym that set me back for a while was MFD which I think means Multi-Function Display.

Sorry about the distracting comment about your problem. The problem itself sounds scary.
 

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Discussion Starter · #5 ·
mrv said:
http://john1701a.com/prius/prius-glossary.htm

As for the lowered MPG, I'd be looking into a sticky rear brake
mrv said:
As soon as I have another event that trips the VSC, the drag and lowered MPG go away, so I believe that it is related to the VSC not releasing. The VSC light never stays on while the drag is occurring, but when I see the light next, the drag stops.
 

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mrv said:
http://john1701a.com/prius/prius-glossary.htm

VSC is an easy one - Toyota lists it. http://www.toyota.com/prius/options.html
http://www.toyota.com/vehicles/2007/pri ... afety.html
http://www.toyota.com/prius/models.html



As for the lowered MPG, I'd be looking into a sticky rear brake (well, at least I'd be having the dealer look into it for me...) Try engaging/disengaging the emergency/parking brake about 10 times, that may help loosen it up and reset it for you without a trip to the dealer.
Also go in reverse and hit brake hard, try few times it might loosen up the sticky rear brake liner. Normally, this procedure is done to adjust the rear brake lining when there is too much play or loose.
 

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VSC kicks in when wheel speeds are different, which I suppose could be caused by the dragging brakes.

I'd have the dealer check all four wheel brakes and speed sensors (and have them show them to you). Since VSC can cut power, that might slow the car, although the VSC light should be on when it happens, the reverse of what you sare experiencing.

I agree, off to the dealer!
 

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VSC, ABS or TC? Each of these are related yet different and they are often confused one for another.

TC: Traction Control. Detects when one or more wheels are spinning at different speeds than the other, so hydraulic braking is applied to the appropriate wheels, and also acceleration is usually backed off automatically. The light with the icon of a car with a squiggly road underneath lights/blinks. No buzzer.

ABS: Anti-lock brakes. Similar to TC, but occurs when driver is applying brakes. In this case the 'sticky wheels' that are spinning slower are released some, or a pulsed release is acchieved so there may be some slippage, but still enough spin to maintain control. The light with the icon of a car with a squiggly road underneath lights/blinks. No buzzer.


VSC: Vehicle Stability Control. It is in your owner's manual. This applies brakes to the appropriate wheels to prevent fishtailing. It is triggered when the yaw/accelerometer sensor detects that the car is turning more than or less than what the steering wheel says you should be turning. The same icon as ABS/TC is illuminated, but a buzzer/beep sounds.

Lately I've noticed a few times in scenarios where the usual TC hesitation would occur, I don't get the abrupt stop that we all complain about, but instead it feels like a hand is holding me back a bit. Another time today, the car felt it was accelerating when I was braking. The ABS light kicked in. My friend's wife described this feeling and attributed it to VSC, but she wasn't turning so I doubt it.

I think I have an explaination for that feeling: Normal gentle braking is achieved through regen using only the front wheels. If a patch of road causes one or both of the wheels to loose grip, then the car is going to coast as if it were in neutral, since the rear wheels aren't being used for braking at this point. The car will sense the discrepency and engage ABS at this point, in which case you now have 4 wheel hydraulic braking.
 

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Discussion Starter · #9 ·
TC - What a drag (was VSC - what a drag)

Thanks for the definition and clarity. I noticed after posting that there was a separate light for VSC than the light I was seeing. Apparently the light I'm having issue with is the Traction Control (TC) light. Last night I hit some more slick road, so I gunned the accellerator to get the front tires to slip, and activate the TC right before my driveway. Hopefully this release what has been stuck. I do believe that I'll have to take it to Toyota, but I'm sure their loaner car will be something that sucks gas. :(

Thanks for the replies, I'll post what Toyota tells me. I'm just afraid that they won't know and will charge me because there aren't any diag lights or codes.

Bill the crwdawg
 

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FYI: The VSC lamp indicates there is a problem with the VSC, just as the ABS light (or brake (0) lamp for that matter) indicates a problem with the brake system. The car with the squiggly road is the indicator that either of the 3 conditions are in play, with VSC accompanied by beeps.
 

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Discussion Starter · #11 ·
TC - What a drag (was VSC - what a drag)

Well I took it to Toyota, they had it for about 4 hours, when I returned, they stated that they backed the brake pads out some because they noticed the drag. I explained that the brakes shouldn't have been the problem because I could put the car in neutral, and it would glide. They explained that it was part of the regenerative braking and that neutral would disengage the regen also. As much as this indicates a problem with the regen, I took it home. I drove for a few miles and it appeared to be back to the normal glide that I'm used to, but eventually returned back to the same drag. I may give them another shot, but my schedule is really busy and it may be a few before I get back.
 

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If the letters VSC light up, then there may be a problem with the VSC ECU, or it needs to be recalibrated. The VSC ECU has an accelerometer, and detects yaw and acceleration/deceleration. If the yaw it detects doesn't match up with the steering you request, then it will engage VSC operation to correct the under/over-steer. The indicator that VSC is in operation is the same as TC and ABS, except the car will also beep.

I would suggest they run through a VSC recalibration.
 
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