Anyone notice their speedometer is off?

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by calbear, May 5, 2013.

Page 1 of 2
  1. calbear

    calbear Member

    Joined:
    Jan 3, 2008
    180
    30
    3
    Location:
    SF Bay Area
    Vehicle:
    2012 Prius Plug-in
    Model:
    N/A
    Based on consistent readings from both a couple GPS units and all of those roadside speed radar signs, I think my PiP's speedometer is reading a couple MPH higher than I'm actually driving.

    Anyone else experience this? Can a dealer verify and adjust if necessary?
     
    #1 calbear, May 5, 2013
  2. cwerdna

    cwerdna Senior Member

    Joined:
    Sep 4, 2005
    12,544
    2,123
    1
    Location:
    SF Bay Area, CA
    Vehicle:
    2006 Prius
    #2 cwerdna, May 5, 2013
  3. DLee

    DLee Junior Member

    Joined:
    Aug 1, 2012
    81
    18
    0
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Advanced
    Speedometer reads 48 mph at 50 mph on my PIPa.
     
    #3 DLee, May 5, 2013
    Don1701 likes this.
  4. iClaudius

    iClaudius Active Member

    Joined:
    Dec 25, 2012
    435
    135
    0
    Location:
    Kansas
    Vehicle:
    2012 Prius
    Model:
    Three
    Yes it's off on all Prius. One solution is go with 205 tires when you re-tire. It corrects the speedometer and the slightly larger tires look better. Lots of threads on the topic with details on effects on mpg and odometer readings.
     
    #4 iClaudius, May 5, 2013
  5. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,166
    50,601
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    so, if i'm traveling 55 (according to the speedo) in the right lane, whe i look in the rearview mirror, that's why the guy behind me looks like he's swearing?:p
     
    #5 bisco, May 5, 2013
  6. Electric Charge

    Electric Charge Active Member

    Joined:
    Sep 22, 2012
    545
    133
    0
    Location:
    Syracuse, NY
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Yep, when someone is riding my bumper, I make sure to do 2MPH more than what the speedo says, just to avoid road rage situations. It sucks that Toyota did this, but it's one of those annoyances we have to live with.
     
    #6 Electric Charge, May 5, 2013
    F8L likes this.
  7. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,081
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    I often do the same.
     
    #7 F8L, May 5, 2013
  8. El Dobro

    El Dobro A Member

    Joined:
    Jul 12, 2011
    7,067
    3,255
    1
    Location:
    NJ
    Vehicle:
    Other Electric Vehicle
    Model:
    N/A
    Not just the Prius, my VWs did the same thing. I add 1mph to what my GPS says I'm doing. :D
     
    #8 El Dobro, May 5, 2013
  9. Electric Charge

    Electric Charge Active Member

    Joined:
    Sep 22, 2012
    545
    133
    0
    Location:
    Syracuse, NY
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Prius is off by 2mph (at least mine is). Makes you wonder how many road rage incidents were caused (and gas wasted by people angrily passing Prius vehicles) by Toyota just to save gas by fooling us via the speedometer ;)
     
    #9 Electric Charge, May 5, 2013
  10. alfon

    alfon Senior Member

    Joined:
    May 17, 2009
    1,370
    270
    0
    Location:
    seaside, oregon
    Vehicle:
    2010 Prius
    Model:
    III
    Lets not forget the MPG computer that seems to almost always be 2-4 mpg optimistic....
     
    #10 alfon, May 5, 2013
    bvoyles and Hi Burrito! like this.
  11. PLSPUSH

    PLSPUSH Active Member

    Joined:
    Mar 22, 2013
    359
    132
    0
    Location:
    Tulsa, Okla.
    when compared to my plug-in garmin gps my speedometer is spot on
     
    #11 PLSPUSH, May 5, 2013
  12. xs650

    xs650 Senior Member

    Joined:
    Jul 2, 2010
    4,539
    1,435
    9
    Location:
    Northern California
    Vehicle:
    2010 Prius
    Model:
    II
    Since most car speedometers read high, I can only conclude that a lot of people driving Prii and being surprised at the speedometer optimism either have their first car or never paid attention to their speedometer accuracy before.
     
    #12 xs650, May 5, 2013
    mtbiker53, fuzzy1 and F8L like this.
  13. mmmodem

    mmmodem Senior Taste Tester

    Joined:
    Nov 17, 2011
    2,732
    1,703
    0
    Location:
    Bay Area, CA
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    Part of the reason may also be the digital aspect. 2 mph is difficult to discern with analog gauges.
     
    #13 mmmodem, May 5, 2013
  14. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,166
    50,601
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    good point.
     
    #14 bisco, May 5, 2013
  15. jfschultz

    jfschultz Active Member

    Joined:
    Mar 15, 2004
    636
    115
    0
    Location:
    Germantown, TN
    Vehicle:
    2020 Prius Prime
    Model:
    Limited
    On my 2004 it varies. At street speeds it reads 1 mph high and 2 mph high at highway speeds.

    Interestingly, there is a button dance on the early 2nd generation to get to a maintenance screen where you can see internal GPS data with the same speed difference.

    iPad ? HD
     
    #15 jfschultz, May 5, 2013
  16. F8L

    F8L Protecting Habitat & AG Lands

    Joined:
    Aug 14, 2006
    19,011
    4,081
    50
    Location:
    Grass Valley, CA.
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    It's not just Toyota. Many manufacturers add this inaccuracy to their speedos.
     
    #16 F8L, May 5, 2013
  17. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

    Joined:
    Nov 27, 2005
    2,790
    1,153
    0
    Location:
    Roseville, CA
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    The speedometers reading high and the disabled screen functionality while the car is moving are both likely the result of demands from the rather conservative Toyota lawyers, rather than any technical reason. Apparently some car manufacturer(s) got sued by customers who got speeding tickets because they relied on a speedometer that read low.
     
    #17 CharlesH, May 5, 2013
  18. bfd

    bfd Plug-In Perpetuator

    Joined:
    Mar 19, 2009
    659
    172
    0
    Location:
    Close to SDSU in the Far Southwest Corner of Cali
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Advanced
    Since my ICE doesn't pop on until I hit 65mph, that's a clue…
     
    #18 bfd, May 5, 2013
  19. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

    Joined:
    Jul 18, 2009
    2,287
    460
    0
    Location:
    Maine
    Vehicle:
    2010 Prius
    Model:
    II
    I obey the speedometer since that's the only legal measurement of speed. However, I try to keep the speedometer exactly at the PSL rather than driving with a lower reported speed to avoid "speeding", which is strictly what you should do.

    If someone's riding my bumper I follow the Maine Driver's Handbook:

     
    #19 ItsNotAboutTheMoney, May 5, 2013
  20. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,166
    50,601
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    wow, 'drive slower' and 'reduce speed slowly', unheard of! those crazy maniacs.:p
     
    #20 bisco, May 5, 2013
    PLSPUSH likes this.
(You must log in or sign up to post here.)
Page 1 of 2