DFCO in the Yaris

Discussion in 'General' started by friedlbug, Feb 4, 2008.

  1. friedlbug

    friedlbug Well-Known Member

    I have a question for anyone who understands DFCO in the AT Yaris. I am under the impression that the DFCO will not kick in if the shifter is in D, but I don't understand why. The way the car downshifts for engine braking, the car feels exactly the same coming down a hill in 4th if I tap the brake pedal to shift down to 3rd or tap the shifter into 3rd. Why would the ECU not use DFCO in the former, but will in the latter? Assuming that this is the case, is it best to drive in D and tap the shifter into 3rd when I want to use DFCO (so as not to lose the FE benefits of OD/4th when accelerating any other time)?

    If you have one, how do you drive your AT Yaris with regard to DFCO?
    Last edited: Feb 4, 2008
  2. BailOut

    BailOut My favorite holiday is Earth Day!


    The 2007 AT models do not enter DFCO in Drive but the 2008 models do. It is an ECU feature in the 2008 models.

    I'm waiting on some more information from Toyota and other 2008 AT drivers before I update the DFCO thread on YarisWorld. If you have an SGII I could use your help.
  3. friedlbug

    friedlbug Well-Known Member

    Thanks, Bail. I was hoping you'd see this. I'm asking for a SGII for my birthday, but that won't happen until July.

    Do you, or anybody, know if the 2008 AT Yaris continues to downshift through 2nd as you slow down in order to keep the RPMs up enough to stay in DFCO? It doesn't feel like it does (I have no tach).
  4. BailOut

    BailOut My favorite holiday is Earth Day!

    No, it doesn't. The only way to make it downshift while remaining in DFCO is to manually select a lower gear.
  5. friedlbug

    friedlbug Well-Known Member

    Does DFCO engage when coasting above a certain RPM in 4th, or must I be in third or lower for DFCO?
  6. BailOut

    BailOut My favorite holiday is Earth Day!

    It holds to the same profile as the other gears, meaning RPM >= 1,100, but what I'm having a hard time getting anyone to pin down is when it starts in Drive. Most folks say it takes a few seconds rather than the near-immediate timing in a manually-selected lower gear, but without an SGII on the fast update setting it's impossible to get anything resembling real timing.

    This is the main reason I haven't put it into the DFCO post on YW.
  7. jcp123

    jcp123 Caliente!

    How does DFCO work in an automatic?! With the viscous coupling it'd just die, wouldn't it? Or does it engage the lockup?
  8. BailOut

    BailOut My favorite holiday is Earth Day!

    It engages the lockup.
  9. ATL

    ATL Well-Known Member

    my 2007 AT yaris' DFCO kicks in when in 4th gear... is it not supposed to?
  10. BailOut

    BailOut My favorite holiday is Earth Day!


    Do you have an SGII to confirm this? What firmware version is on the SGII?

    If what you say is accurate then it means the 4th gear DFCO feature for the AT models was snuck in during the middle of the model year and that's going to create a lot of work for me. ;)
  11. yi5hedr3

    yi5hedr3 Well-Known Member

    My 08 AT Yaris does too. It continues to work as it downshifts through gears and only drops out when the RPMs fall too low, or when I step on the gas. There is a pause for a couple seconds after letting off the gas before the DCFO kicks in though. :)
  12. friedlbug

    friedlbug Well-Known Member

    ATL, you're getting ~40MPG in the AT Yaris? That gives me hope. My best tank so far is 36 on mostly highways during winter, but I'm still learning. Good to see a fellow AT Yaris driver getting good mileage.
  13. kdawg58

    kdawg58 New Member

    Hi, first post here...

    just wanted to let ya'll know i've got an 07 liftback with a SGII. i just got the SG a couple of weeks ago, so i assume it's the lastest and greatest. anyway, i can confirm my 07 does have DFCO in overdrive. the MPG reads 9999 evertime i coast above 30 MPH or so. i bought the car in August if that helps any...
  14. yi5hedr3

    yi5hedr3 Well-Known Member

    Yep - just to be sure, try it at highway speeds too! :woot:

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