Last post on Feb 26, 2013 at 8:04 PM
You are in the Toyota Venza
What is this discussion about?
Toyota Venza, SUV
#1166 of 1243 Re: Huh? [volkov]
Oct 07, 2009 (6:48 pm)
AWD = a form of part-time 4WD that automatically engages the opposite drive wheels but only in conditions wherein the surface is deemed, determined, to be of a nature that would not result in a significant level of driveline windup, tire scrubbing, surface of low tractivity. Probably best, better, defined for purposes of buyer understanding as either F/awd or R/awd.
F/awd = a vehicle that is based on an otherwise FWD vehicle and:
A) Primarily drives only the front wheels. Examples = Ford Escape, Mazda CX-7, Toyota Venza, 2010 RX350.
B. Provides continuous drive to all 4 wheels but normally with POOR drive coupling to the rear wheels. Definite front wheel drive BIAS, say 95/5, in highly tractive conditions. Examples = Chrysler T&C minivan, RX300.
C. A system wherein all wheels are driven at an equal level provided all four wheels have roughly equal surface traction. Otherwise, disparate traction, TC is used to sustain a high level of engine traction. Examples = Toyota Highlander, Sienna, and RX330.
Have I missed one..??
#1168 of 1243 Re: Huh? [steve_]
Oct 08, 2009 (7:16 am)
thanks, hard to know what each manufacturer is giving you and if it even works!
This old video shows that. It was in your link,
#1169 of 1243 Re: Huh? [roho1]
Oct 08, 2009 (8:33 am)
More importantly, does it work for what you want. Get out and try them in the situations you want the AWD for. Gravel, snow, ice or just better handling in emergency situations. Unfortunately, deep snow can be very difficult to try because dealers don't like sending their cars out in that weather.
My favourite first step is rapid acceleration from a stop into a right hand turn while sitting on a loose surface (snow or gravel). Forget the mechanics of the AWD, you'll see and feel the real world differences instantly. And for anyone who thinks it's an artificial test, I do it almost every morning as I turn off my residential street onto a busy boulevard with fast moving traffic. Road surface at that STOP sign is glazed ice about 4 months of the year.
#1170 of 1243 Re: Huh? [volkov]
Oct 08, 2009 (9:06 am)
"..rapid acceleration from a stop into a right turn..."
See "..turn onto.." just beyond halfway down this post.
I have recently acquired a 04 Lexus RX 330 with 31K on it and all the goodies possible for it. Right now do to me still being a student and the crazy insurance premium that I would have me and my dad decided to share it for the time and put it under his name.
Anyway, the issue is when the car is in motion and occasionally from a dead stop you can hammer the gas pedal, and go at it aggressively then a normal acceleration and the damn this wont move.:ugh3: The first time I noticed it was I was getting on I-83 and i could merge into this one spot if i got up to speed quickly. So I pushed the pedal all the way down.......and the SUV just was like im going to take my time on this. Was very dangerous!
[b]In the circumstance you describe the DBW/e-throttle firmware is intentionally designed to NOT allow the engine to begin increasing RPM and/or torque levels until the transaxle has completed a downshift, REQUIRED downshift, as a result of the "new" gas pedal position. The delay is usually only on the order of 1-2 seconds but highly notable, and inherently HAZARDOUS in the wrong circumstance.
"..occasionally from a dead stop.."
There is likely NO FWD or F/awd vehicle in the market today that when coasting down, or even braking down, to a dead stop will begin shifting down into 1st gear automatically until a few hundred milliseconds AFTER the vehicle has come to a FULL/complete stop. Then allow a second or 2 for the downshift to complete. To do so would simply increase the HAZARDS of FWD an/or F/awd vehicle operating, POTENTUALLY operating, on a slippery roadbed surface.
There are many posts here and abouts wherein owners of these vehicles are complaining of loss of braking power, or a "lunge" forward at 10-5 MPH during coastdowns, braking or no. This is mostly the result of a new technique being used to extend FE via the use "fuel cut" procedures. As you coastdown from a higher speed with the throttle fully closed the engine's fuel flow will be cut completely. Then to prevent an inadvertent engine stall the transaxle is downshifted, accordingly, as roadspeed declines. Except at ~10-5MPH the resulting engine braking, engine braking on the FRONT, could potentually prove to be HAZARDOUS should it happen that the roadbed be slippery. So, not only is the engine NOT to downshift to 1st and was often the case in days gone past, but an upshift often occurs.
As you may note the same hazards do not exist, do not equally exist, for RWD an/or R/awd so the downshift to 1st for those vehicles may be as always.
The time my father noticed it, he was at a dead stop at a stop sign. He saw a gap on the road he was going to turn onto and once again he pressed the accelerator about 3/4 the way down and the SUV again decided to takes its time moving. Once again very dangerous!
[b]"..turn onto.." "...pressed the accelerator.."
There is an aspect of the control system, VSC/TRAC, that will NOT allow a rapid acceleration into a tight turn from a dead stop. Anti-rollover functionality or maybe even pre-emptive action against the STRONG potential for loss of directional control when asking the front tires to perform, at HIGH level, both functions, lateral and longitudinal traction, simultaneously. In any case, SOP (my '01 F/awd RX300 does this), you MUST fully lift the gas pedal in order to regain throttle control.[/b]
I will admit, I have gotten used to this issue and found ways to drive the RX to compensate for this problem... However my dad is not so lucky with this. He went from my 96 V6 Camry which is cable throttle to his 05 4Runner
[b]First, the 4runner is a R/awd vehicle and therefore it is NOT as likely to need pre-emptive dethrottling of the engine to prevent loss of directional control in the stated instance. I think I have read somewhere that the 4runner, when in R/awd mode, even begins removing engine torque from the front wheels, dedicating them to lateral traction, in this very circumstance.
Second, the 4runner' engine and transmission are mounted longitudnally so there was no need back in '98 to begin squeezing and/or eliminating transaxle components altogether due to the limited space and need for GROWING transaxle fucntionality[/b]
which is throttle by wire, and expected to have no problems since you can barely tell the difference in response between the 4runnerlongitudinallyfunctionality and the Camry.
We have talked to some shops to get their thoughts and they said three is something wrong, but that they do not know what it could be. Also there is no Engine Check Light at all except on start up the car and normal diagnostics check. I'm about to take it to a dealer to get them to check it, was hoping to get some ideas here first. My thoughts are there is some issue with the transmission controller, Traction Control, throttle body and wire harnesses, or the AWD Controller.
wwest abolition hesitation -dfg
for more detailed info.
#1171 of 1243 Re: Huh? [wwest]
Oct 08, 2009 (9:38 am)
Keep in mind, these VDC/TC systems are always about a balance between power and control. The Toyo system is the most intrusive and control biased I have driven and there are many complaints about that on various boards.
It's why my personal car is a Subaru. The trade-off, as CR loves to point out is that I can oversteer the Subaru if I'm too aggressive. It comes back almost instantly and I know the threshold so it's not a surprise and doesn't bother me. Toyotas are extremely hard to wash the back end, and therefore are preferred by the many people who have spent their entire driving life with FWD. Some will have a fit when they fish-tail and have no idea what to do when it happens. I also think some of those same drivers tend to be more abrupt on the accelerator. FWD doesn't punish that in poor traction the way RWD or AWD can so they've never learned to be gentle on initial throttle. In many cases, those driving habits are partly to blame for the VSC kicking in. FWIW my wife knows the rear end traction threshold too, and she never slides in the Subaru.
#1172 of 1243 Re: Huh? [volkov]
Oct 08, 2009 (12:19 pm)
Toyota is simply reacting, correctly, to the fact that the general driving public is dumbing down more and more as each day goes by.
#1173 of 1243 Re: Huh? [wwest]
Oct 08, 2009 (4:04 pm)
It would seem that Toyota is providing a system that doesn't work as claimed. The 07 Highlander has full time 4wd with traction control but the video shows their system won't move the Highlander when the front wheels spin.
Is that reacting?
#1174 of 1243 Re: Huh? [roho1]
Oct 08, 2009 (5:05 pm)
"..is that reacting?.."
The more the public has dumbed down the easier it si to sell non-functional features.
The Toyota Highlander, Sienna, and the Lexus RX series have not had a functional F/awd system.....FOREVER....!!
There is, can be no, full time 4WD.
But, in a literal sense the system that Toyota uses in the Highlander & Sienna, and Lexus in the RX series truly is full-time 4WD. Virtually useless full-time 4WD but full-time 4WD none-the-less.
But that's how Toyota's marketing gets away with misleading the buying public so vey easily. Marketing is not lying and the buying public is in the belief that if it says 4WD then that's what they need.
How can that be explained, reconcilled..??
The Toyota 4WD system as used above is 4WD just as long as one doesn't have need of REAL 4WD.
#1175 of 1243 toyota Venza Smart Key
Oct 09, 2009 (4:52 pm)
No one at the dealer knows how to operate it.
Are the doors suppose to lock automatically when you walk away from the vehicle with the smart key in your pocket or purse???.
I just bought the AWD V today