By on February 1, 2010

Update: A portal to all of TTAC’s related articles on Toyota gas pedals is here:

Toyota has released their official “fix” for the sticky CTS-made gas pedals on the recalled models affected. From their graphic, it’s difficult to understand what parts are involved, and how they work. Thanks to our recent tear-down of the CTS pedal, we have the pictures and familiarity with the unit to explain it in detail.

The pedal is designed to have a certain amount of friction or hysteresis built in. This is done so that the fatigue of pressing the pedal continually is not onerous or becomes fatiguing. It also replicates the friction that would normally be present in a conventional throttle cable as it passes through its housing. A throttle assembly without the correct amount of friction or hysteresis would be very difficult to control smoothly.

Obviously, the exact amount of friction designed into the unit is very critical, so that the pedal returns as soon as the pressure is removed or reduced. The relationship of the spring pressure and built in friction must be stable and consistent. Toyota has stated that that is not always the case with the recalled CTS units, and that the degree of friction can increase over time due to wear and/or condensation, to the extent that the friction is greater than the pressure from the return spring. This would potentially cause a gas pedal to return slowly, unevenly, or not at all from the point where it was released.

This problem would not be the cause of “unintended acceleration” to the extent that the pedal would only stay open as much as it was before being released, although it could well be experienced as such. If the car was being accelerated briskly as on an on-ramp or hill, and the pedal stuck in that degree of openness, the car could well feel like it was accelerating on its own after the target speed was attained and the foot pressure reduced.

The affected part is in the lower center of the photo above (A), and in more detail in the one below. It is integral to the part that retains the return spring. The friction area is seen as the small “teeth” or “ears” protruding to the left at the very bottom of the picture. These two teeth ride in the two grooves of the pedal assembly (B), and are held against each other when the spring assembly is locked into position.  The area of friction is seen as the grayish worn area on the teeth just beyond of the (crude) arrow.

From Toyota’s graphic (below) and from my experience handling the unit, it appears that there is a certain amount of free play of the spring retainer/friction block unit. In Toyota’s graphic below, it shows that unit tilting slightly, perhaps due to too much free play or wear of the plastic components. The steel reinforcement bar (red unit below) is apparently intended to stabilize the angle of the spring retainer/friction block unit, to ensure that the degree of friction is either more consistent or is compensated for the wear that has occurred.

We intend to secure a pedal unit and the steel reinforcement bar as soon as they are available for further examination and evaluation.

Update: see follow-up story on replicating the “fix” here. And the final piece comparing the Denso with the CTS unit, and our conclusion and recommendation is here.

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33 Comments on “Toyota Gas Pedal Fix Explained – With Exclusive Photos...”


  • avatar
    criminalenterprise

    Whither the Denso unit? Does it have the same meshing parts?

  • avatar
    Paul Niedermeyer

    The Denso unit is very different; it clearly doesn’t have the same friction elements. In looking over my Denso pictures, it’s not exctly clear to me how it’s built-in friction is achieved. Perhaps the plastic-to-plastic bearing area has the right amount of hysteresis, or possibly the way the spring rubs against the sides of its housin, which is clearly visible in the photos of the other article.
    If I can get a hold of the Denso unit again, I will examine it further for that particular aspect of its design and function.

    • 0 avatar
      Robert.Walter

      Denso hysteresis and design weakness…

      Denso builds its hysteresis by compressing and elongating the spring pair thru a curved path as defined by the curved tracks inside the housing and the lid. Compress the spring along a curve and it will want to buckle, allow it to elongate and it will try to straighten itself out. These two mechanisms compression and elongation should work quite differently in this unit.

      Long-term durability wise, I wonder how durable the extension of the arm between the hub of the lever and the spring is … it is necked down between these two features … In the event of embrittlement of the plastic arm, or some kind of fracture of the spring and jamming of the assembly, preventing compression of the spring … if this small arm fails, it will be equal to a WOT throttle position because the spring will not be able to return the lever to the idle positon.

  • avatar
    cdotson

    This would appear to be a result of plastic creep. The “ridge” on the back side of the spring cup effectively reduces the area which resists the compressive load of the spring. As the ridge flattens and possible pockets the mating surface of the fixed bracket portion of the pedal it creates wiggle room for the spring cup/friction arm to create a rocking motion. With the pedal down, the arm rocks and jams the friction teeth into over-engaging the grooves on the pedal arm, binding the thing up.

    This “fix” would remove the concentrated load from an easily deformable part. Bad plastic design methodology.

    • 0 avatar
      Eric Bryant

      The “reinforcement bar” doesn’t appear to be intended to mitigate the symptoms of creep; instead, it seems to simply limit the travel of the hysteresis lever as the pedal is depressed, which thus reduces the amount of hysteresis at large pedal travels and decreases the likelihood of excessive friction.

  • avatar
    ttacfan

    Was there a $15 price mentioned in regards to the Toyota gas pedal? Was it for the entire assembly or for some particular part? The longer I look at this the harder is for me to believe that this assembly can be produced for $15. I browsed some supply sites for DIY EVs and it looks like gas pedals with similar functionality are sold at just under $150.

  • avatar
    Paul Niedermeyer

    I don’t have it in front of me, but I believe that Toyota stated it cost them $15 as part of their disclosure of the potential financial impact to the company. Toyota’s parts retail price is about $120. Given typical mark-ups and the simplicity of the unit, the $15 production cost seems in line. I hear $120 Nikes cost less than $15 to make. Maybe Bertel Schmitt has a comment on that.

    • 0 avatar
      Robert.Walter

      I once tried to determine what our competitor’s parts cost our OEM customer by comparing the OEM’s PO (purchase order) to us against the dealer cost price and the parts counter retail price to the customer.

      Exercise was an abject failure.

      All I was able to determine is that the multiple between the supplier’s PO price and the OEM’s service part price can vary wildly, and that OEM’s really stick it to their customers (as Bertel indicated previously, IIRC, 1/3 of VW sales income was due to Ersatzteile”.)

      BTW, I once changed the oil in a friends Camry, in the mid-1980s, and I was amazed that the oil filter price from the Toyota dealer was comparable in price to the aftrmarket part at the parts store…

  • avatar
    Boff

    So…the throttle is supposed to be sticky. How ironic!

    TTAC is to be congratulated for covering this confusing story so effectively.

  • avatar
    MidLifeCelica

    Now that I think I understand how the parts fit together and move in action…WTF? When in the ‘correct’ position, the central ‘peak’ on the main housing and the ‘valley’ on part A don’t touch, therefore serving no purpose other than to cause more trouble when the unit shifts out of position. They don’t provide support, or aid in alignment, or add strength. The middle two orange dot friction points on the current model closeup would not exist if the part was not ‘W’ shaped for no reason. I could see this assembly jamming in such a way that pulling the pedal back from behind might not work. I’m thinking Chinese finger puzzle-style lockup.

    • 0 avatar
      Robert.Walter

      I must also admit that I was unclear that the wedge function was occurring on the back of the cup-lip … I saw this protrusion, and as written elsewhere, thought this might have a function, but my inability (mistake) of not properly mentally integrating the info of the teardown pics and the graphic of the fix.

      By way of excusing this error, I’d only like to say the pics at minimum were a bit disorienting and at maximum a bit confusing. I’m not complaining, as I’m thankful to Paul for doing this legwork, and I recognize again the value of having a piece of hardware to “play” with … in my years of Competitive Analysis, I time and again learned the value of “fingering the object of one’s desire.

      This said, I still stand by my critiques regarding the use of a friction-based solution … as said before friction and the factors influincing it are myriad. (Maybe Bertel knows of the ‘Fat Bavarian’ test and its relationship to friction and structural ridgidity!)

      I’m still looking forward to more information to really see what is going on.

  • avatar
    Hank

    I’m definitely buying that it’s easily a $15 part. Looks like something IKEA could have produced in orange and flat-packed for $7.

    I don’t know why I’ve found all this so interesting, owning a Chevy and a Honda, but I do appreciate all the effort that TTAC and the B&B have gone to to break it down. Very interesting.

  • avatar
    mjz

    IMO Toyota is trying to baffle us with bull$hit. First it was the floor mats. Now they are trying to tell us it’s a “stuck” accelerator pedal. This explanation does not make any sense. If you read the accounts of people involved, the cars simply rocket out of control, basically without the driver doing anything to cause it. For the “stuck” pedal story to hold any water, would’t the driver have to mash the pedal all the way to the floor for it to “stick” in the full throttle position? How has Mrs Smith who is driving down the freeway with the cruise control on caused the accelerator pedal to get “stuck” in the full trottle position? It just doesn’t make sense. I think the real issue might have something to do with their “drive-by-wire” computer system, which may be affected intermitently by electronic “noise” like cell phones, etc.

    • 0 avatar
      cdotson

      I took driver’s education in 1995. Seeing as how drive-by-wire still isn’t 100% industry standard today (or is it? Seems there are still throttle cable vechiles sold), I bet driver’s ed still teaches the same thing:

      If the throttle sticks; smack it good a couple times to see if you can free it up. Thereby pushing it to the floor.

      Maybe it’s just because my instructor was an idiot redneck, but I distinctly remember this piece of (what even then I thought was) idiotic advice.

    • 0 avatar
      Hippo

      Many people in US are very slow drivers but have the habit of applying full power off stops or in traffic to cut in front of others without using signals. The pedal doesn’t even have to fully stick, just return slower, and they would claim “the car took off”.

      This would be consistent with the reports that dealer people could not find anything immediately after the “event”. It would also cut the available time to deal with it significantly and of course the drivers would not admit to what they were really doing. Lots of drivers pretend to be Mother Theresa but drive like pigs when they think they are anonymous in their cage.

      Not to make a excuse for the pedal, but one has to use some perspective.

  • avatar
    ott

    “How has Mrs Smith who is driving down the freeway with the cruise control on caused the accelerator pedal to get “stuck” in the full trottle position? It just doesn’t make sense. I think the real issue might have something to do with their “drive-by-wire” computer system, which may be affected intermitently by electronic “noise” like cell phones, etc.”

    –Now THAT is a scary thought.

  • avatar
    Hippo

    This makes much more sense then the “washer” shown a few days ago, and corresponds with what is being reported in Europe.

  • avatar
    lostjr

    CTS is challenging some of Toyota’s claims:

    “CTS Corp. of Elkhart, Ind., said in a statement that it had “deep concern that there is widespread confusion and incorrect information” about its products linked to the sudden-acceleration issue.

    “The problem of sudden unintended acceleration has been reported to have existed in some Lexus vehicles and Toyota vehicles going back to 1999, when CTS did not even make this product for any customer,” the company said.

    Toyota began using CTS-made pedals in the 2005 model year.

    On Jan. 21, Toyota told federal regulators that CTS pedals were susceptible to moisture and could stick, forcing the recall of 2.3 million cars and trucks. CTS acknowledged that a tiny number of pedals had a rare condition that could cause a slow return to idle position, but it denied that this condition could cause unintended acceleration and said that it knew of no accidents or injuries caused by the issue.”

    …..

    “The automaker also uses pedals supplied by Denso Corp., a Japanese company with North American headquarters in suburban Detroit, but has said those do not appear to be defective.

    However, the Times review of federal safety records shows several instances of complaints of stuck pedals on vehicles built in Japan, which Toyota has said are not subject to the recall. For example, one complaint, filed two years ago, told of a 2007 Japanese-built Camry in Maryland with a pedal that “stuck to the floor.’”

    http://www.latimes.com/business/la-fi-toyota-pedal30-2010jan30,0,4416445,print.story

  • avatar
    ASISEEIT

    Just an observation upon reading most of the comments from everyone on this Toyota pedal issue. There isn’t any Toyota bashing! Evidently having the good record Toyota has keeps the bashing to a bare minimum. I would also like to state in my opinion if this was an American auto producer ALL HELL WOULD BREAK LOOSE! This is not to argue but to state an observation.

  • avatar
    csf

    Sorry, but I also posted this in another older thread. I do not believe this simply a mechanical problem with only the CTS pedals – there are now reports of 2009 and 2010 Camry’s crashing. How much wear can really be on a pedal only a year old, even if it is the CTS unit? Are they that poorly designed and built that they won’t last a year? I doubt it. And isn’t it unbelievable they threw poor CTS out there – I can’t remember the media ever blaming the supplier of any part recalled by GM or Chrysler.

    Instead, I also believe there must be a software problem they are working on but will not admit. Of course, I have good reason to be skeptical of Toyota. I had a V6 Camry over 10 years ago that suffered a complete engine failure after 46,000 miles. My dealer and Toyota blamed this on me for performing my own oil changes, which I had always done.

    They wanted $8000 for a new engine installed, which I could not afford. So I had to trade the Camry, not running, on a used Ford Contour, and roll the $5000 I was now upside down on the damaged Camry into the Contour loan. I paid way over book value for that Contour so the Ford dealer would take the Camry off my hands.

    Years later, after thousands of V6 engine failures in many vehicles, class action suits and government investigations, Toyota admitted they knew their engines were running too hot, baking the oil and causing the engines to sludge and fail. They were forced to reimburse owners for their engine repairs – but I got nothing because I didn’t repair my car and had no receipts to submit. I lost over $5000 on that Camry after only 46,000 miles.

    Toyota will never see another dime of my hard earned money. And based their past actions, I fully believe they are hiding the full truth about these sudden accleration issues. Over the past decade, despite Consumer Reports’ bias, Toyota has cut corners, cut quality, and been dishonest and quick to blame their customers when problems occur. I feel terrible for the current owners who have been injured or even killed. But Toyota is getting what they finally deserve. Maybe more Americans will think twice now before they blindly walk into their local Toyota store and put down their money without even considering another brand.

  • avatar
    digdeeper

    Omg…talk about buyin some time! Toyota is a great company but everyone needs to understand what is happening. There is not a problem with the floormats or any problem with tension or return tension on this pedal. This problem will not go away with the absurd fix they are proclaiming. If you know some one driving one of these vehicles please advise them to rent a car or sell it. The problem pertains to the Control By Wire system. There is an electrical gremilin and CTS nor Toyota can find the source. Most of these cars are not simply holding speed after pedal is released…they are acclerating meaning the BCM is detecting/receiving a signal from pedal assembly to accelerate.

    The cost to retrofit these vehicles to a standard cable sytem and reprogram the BCM is not a option financially for Toyota. Estimating around 1400 per vehicle with also a very slight drop in mpg on every vehicle. I’m am not a Toyota (or CTS…I’m a Hoosier) basher, they make 2 of the best bang for your buck vehicles imho. But there is a lot of misinformation being flooded by Toyota as well as the AP.

    What’s sad is the press seems so giddy to get the next revelation in this story not one outlet has questioned “why did they blame the floormats if not to buytime or fool”… a few keen posters above caught though…..

  • avatar
    GuardiAngel

    I had a 1982 model Toyota Tercel in which the accelerator pedal stuck a couple of times. I had the car till 1996 and the sticking happened sometime in the late years. Is the design of that pedal somehow similar to the modern one’s causing the problem?

  • avatar
    ASISEEIT

    To reiterate in plain terms it seems “most” are playing softball with Toyota and even sometimes kissing their ASS! Maybe they’re right, I don’t know and hopefully this is just a simple design flaw and a carpet mat problem. I haven’t had anybody in my family hurt or killed by “The Problems” at Toyota so I’ll wait and see!

  • avatar
    BJones

    I’m not an engineer but this seems a dubious design. I would think a friction mechanism would have either two facing disks, like disk brakes and the Denso pedal, or concentric pads and drum, like a drum brake. This way, as the material wears you still have a constant surface area of contact and therefore constant friction.

    With the wedge and groove design like you see here, as the plastic wears the wedge rides farther and farther down in the groove. That increase the area of contact, which increases friction, which leads to more wear, etc. It’s not hard to see the wedge suddenly binding in the groove and making the pedal stick.

    The shim keeps the wedge from penetrating too far into the groove. This would prevent sticking but would, I think, lessen the friction over time as the plastic wears and the spring can no longer make up the difference.

    Just a gut feel.

  • avatar
    rakhmatulla

    Guys, if the throttle pedal sticks there is a simple remedy: shift to neutral, or turn the power key off. It is that simple!
    I drive both a Camry and Lexus with this kind of pedal, and they never sticked. Looks like car corporations’ games.

  • avatar
    JAQUEBAUER

    My daughter took her 2009 Camry in to the dealer today for the Gas Pedal recall, and were very suprised and dissapointed with the “fix” that Toyota has chosen for this problem. We picked the car up, getting the keys and a copy of the repair order from the cashier. We were not told about any precautions to take or be aware of changes in the operation of the car. The Repair order indicated that the cars computer was reprogrammed, and some work was done on the gas pedal. I asked her to test drive the car in the dealers parking lot before she went home, to check for any problems.
    There were 2 issues she found unacceptable, that I want to talk about here.
    First, she said the feel of the accelerator had changed greatly, that it took very little foot pressure to move the pedal, that it felt very light and that she was startled when she pulled out from the parking space at how fast the car jerked forward. It seems that the fix reduced the force needed to move the accelerator greatly, and she had not expected the change, and it would take some time to get used to.
    Secondly, the other part of the fix was to “chew off” the bottom of the gas pedal, reducing its length to about 4 inches. I say “chewed off” because the cut was very sloppy, looking like a racoon has eaten the bottom end of the pedal off. It appears that they did not replace the floor mat, as it looked like that same 10 month old mat.
    After calling both conditions to the attention of the service manager, he acted like we were the only one of “thousands” to complain about the recall fix. . We did NOT get acknowledgement from him that we should have been informed about the change in pedal pressure, and that an unsuspecting person might have an accident because of this change. As for the gas pedal fix, he said that “we only do what is dictated to us by Toyota.” I asked if the cutting of the pedal was an interium fix, or the final fix, and did he agree with me that the gas pedal cutting was a sloppy fix for a $25,000 car ? His reply was to repeat that “this is what the factory has told us to do.” This service manager did not know if this was the final fix..

    At a minimum, we should have been warned that there would be a change in the pressure required to depress that gas pedal, and to be careful when first driving the car. I also feel that the removal of bottom part of the gas pedal was done very sloppy, and did not conform to any quality standard in todays manufacturing world. I am sure that Toyota would not ship a new Camry with a “chewed off” gas pedal, and that this “fix” was a “cheap way out”
    If we are now safer in our Toyota Camry because of this recall, a “chewed off” gas pedal might seem like a petty complaint, and would be acceptable as an interium countermeasure. If this is the final solution, then the “sloppy” nature of the fix makes me wonder where else is Toyota being “sloppy”

    • 0 avatar
      mewzikgal

      I TOTALLY AGREE WITH YOU. I JUST HAD MY CAMRY REPAIRED AND I TOO NOTICED THE LIGHT PEDAL. IT TOOK ME AWHILE TO GET USED TO IT. I ALSO NOTICE THE JUMPING RPM’S. I THINK TOYOTA SHOULD OFFER A REPLACEMENT PEDAL AND NOT THE PIECE OF CRAP THAT THEY TURNED MY PEDAL INTO. I WILL BE ARBITRATING FOR A NEW PEDAL. THIS IS TOTALLY UNACCEPTABLE TO ME. I DOUBT THAT THEY WILL BE PUTTING THOSE ON NEW CARS, OR WILL THEY?


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