Speed is multiplied by 1.6 when connected to MB CarPlay — TomTom Community

Speed is multiplied by 1.6 when connected to MB CarPlay

Joachim_RJoachim_R Posts: 4 [Apprentice Traveler]
Here is a strange phenomenon: when I connect my iPhone running the new TomTom Go App with the Carplay system of my car the speed indicated on the handset is multiplied by 1.6. It seems to be doing a mile-to-KM/H conversion. So when I’m doing 80km/h the TomTom app shows 128km/h. The little icon on the Carplay screen (with the max speed on that road) is always showing the exclamation mark indicating that I’m speeding. When I disconnect the phone from the CarPlay USB-port it turns back to the normal km/h speed.
The car is a Mercedes E-class with the command system (MY 2017). When I connect the same iPhone with the audio system of my wife’s car, it works fine (she has a recent model Peugeot).
The error is annoying because I can’t see my average speed during an ‘average speed check’ on the motorway. Also I miss the route bar on the right of the CarPlay screen, that is a very useful feature of the TomTom Go App. It’s a bit of an disappointment this new Go app…

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  • PrivateerUKPrivateerUK Posts: 361 [Supreme Pioneer]
    edited June 2019
    Hi @Joachim_R,
    Joachim_R wrote: »
    Here is a strange phenomenon: when I connect my iPhone running the new TomTom Go App with the Carplay system of my car the speed indicated on the handset is multiplied by 1.6. It seems to be doing a mile-to-KM/H conversion. So when I’m doing 80km/h the TomTom app shows 128km/h. The little icon on the Carplay screen (with the max speed on that road) is always showing the exclamation mark indicating that I’m speeding. When I disconnect the phone from the CarPlay USB-port it turns back to the normal km/h speed.
    What country are you based?
    Do you normally use km/h or MPH?

    I'm reading this as when connected to your MB CarPlay head, your iPhone TomTom app displays the speed x 1.6, is that correct?

    Does that same happen with other iOS apps (Google, Waze, Apple maps, etc) on your iPhone and the same MB CarPlay?

    Have you checked the MB CarPlay manual?

    Regards,
  • Joachim_RJoachim_R Posts: 4 [Apprentice Traveler]
    Hi PrivateerUK,

    I'm in the Netherlands and use km/h.

    Yes, you're right: when I connect to the USB connector with CarPlay support (my car has 2 USB ports, the other one does not start CarPlay when I connect) the speed in the bottom of my handset screen shows the speed in KM/H multiplied with 1.6

    Google Maps and Apple Maps don't show the actual speed on the screen and I never used Waze so I can't really tell.

    The MB CarPlay manual does state that the speed of the car is shared with the iPhone navigation apps to prevent problems when when driving through tunnels etc. So instead of using the iPhone GPS antenna TT Go app is probably using the actual speed from the car. That might be the source of the problem but I can't change the settings from km/h to mph or vice-versa. The speedometer of the car is showing the correct speed in KM/H (or I have been driving very slowly in the past 2 years...)

    Hope this is helpful. Thanks for your support!

    BR

  • PrivateerUKPrivateerUK Posts: 361 [Supreme Pioneer]
    Hi @Joachim_R

    That sounds like MB efficiency to provide speed via USB cable for dealing with satellite drop outs in tunnels etc.

    I don’t have CarPlay but I have an idea.

    Please check your settings of units in both CarPlay and phone app

    Settings / units

    Both should be on automatic or km

    If they’re not change them

    If they are both already synchronised ie both automatic or both km then change you phone to miles as a test.

    Regards,
  • Joachim_RJoachim_R Posts: 4 [Apprentice Traveler]
    Hi PrivateerUK,

    I did some testing. When I switch the settings in my car from KM/H to MPH It will only change the value displayed on the digital speedometer on the car’s dashboard. I didn’t find a way to influence the feed it is sending to the CarPlay USB interface. That value seems to be fixed in km/h.

    The setting of the TT Go app was on ‘automatic’ and when I switch it to km/h it makes no difference it still multiplies the km/h value from the car by 1.6. If I change the app to mph it just copies the value from the car and displays it as mph. So I have 80 km/h on the dashboard of the car and 80 mph on the TT Go screen on my iPhone. The 2 values match exactly which proves that the TT app is indeed using the speed value from the car. (When the iPhone uses its own calculated GPS speed the value in km/h on the phone screen is usually 4 km’s below the speed reading on the dashboard.)

    So I think we located the problem: TomTom is interpreting the feed from the MB CarPlay interface as a mph value while it is actually km/h. Not sure if this is a problem with MB only, like I wrote above in my wife’s Peugeot it seems to be functioning fine but Peugeot
    might not share the speed reading from the car with the connected CarPlay device.

    Thanks for your help, I hope the TomTom developers are reading this and will fix it in the next version.

    Best regards

  • PrivateerUKPrivateerUK Posts: 361 [Supreme Pioneer]
    Hi @Joachim_R
    Joachim_R wrote: »
    So I think we located the problem: TomTom is interpreting the feed from the MB CarPlay interface as a mph value while it is actually km/h. Not sure if this is a problem with MB only, like I wrote above in my wife’s Peugeot it seems to be functioning fine but Peugeot
    might not share the speed reading from the car with the connected CarPlay device.
    That's good news that you've located the problem. Yes, it does seem that TomTom needs to be able to determine not only the speed from the MB CarPlay interface but also the units, i.e. either km/h or MPH. As I've previously said MB is normally efficient and I suspect that their CarPlay interface already transmits the units (km/h or MPH) so it's probably a TomTom issue. You need to decide whether you want to use the speed shown on your CarPlay or on your MB's dashboard and then set the units on your MB car to the appropriate one.

    Hopefully, TomTom is monitoring this thread but as a precaution please contact your local TomTom support helpdesk as I'm sure a lot of other people will encounter the same problem.

    Joachim_R wrote: »
    When the iPhone uses its own calculated GPS speed the value in km/h on the phone screen is usually 4 km’s below the speed reading on the dashboard.
    Out of interest, is your MB car a Netherlands registered vehicle or an import, possibly from the UK? I ask because UK cars are supposed to overread the actual speed on the speedometer but I thought that cars registered in other countries should show the actual speed.

    Regards,
  • Joachim_RJoachim_R Posts: 4 [Apprentice Traveler]
    Hi PrivateerUK,

    The car is NL spec but it is not uncommon that speedometers exaggerate a bit. I saw the same thing with previous cars and also rentals in other countries. The TomTom Go app is quite accurate. That’s why I like to have the App beside the built-in satnav system. (And because it is better and quicker with traffic jams and calculating alternative routes)

    All the best!
  • BertieRossiBertieRossi Posts: 1 [New Seeker]
    I have the same (in reverse) here in the UK. Speed limit shown correctly in mph....actual speed shown in kmh (1.6 x faster) so constantly “speeding”.
    Mine is January 2018 registered and I’m booked in for a software check and update at the local dealer.
    Waze has an identical problem and also the gps position drifts wildly....
  • Not quite lostNot quite lost Posts: 13 [Master Explorer]
    Arghhh! I bought a high-end iPhone specifically so that I could run TomTom through Apple CarPlay ... but like yours, my TomTom is ridiculously over-reading through CarPlay! I am in the UK (so MPH) and I have a 2018 Ford Fiesta ST Line X.

    At 70 mph on the speedometer, the TomTom reads 77, with the irritating red warning. At 30 mph on the speedometer, it reads 35 mph.

    This is really disappointing as I have used stand-alone TomToms for many years and they have always been excellent (which is why I abandoned a fully operational, top notch Android phone to buy an iPhone).

    I contacted TomTom about this well before a recent update (it was previously only showing 2mph over) but no action followed. Now, the speed measurement is a joke!

    In desperation, I tried Google Maps today, and was pleasantly surprised. OK, it doesn’t show speed but at least it is not showing incorrect information either!

    Come on TomTom - it’s about time you addressed this, before you lose customers!
  • PrivateerUKPrivateerUK Posts: 361 [Supreme Pioneer]
    Hi @Not quite lost.

    A few notes:
    • You're in the UK (so using miles and MPH as units)
    • You have a 2018 Ford Fiesta ST Line X
    • You're using Apple CarPlay, at an indicated 70 mph (your car's speedometer), CarPlay shows 77mph.

    What happens when you're not using CarPlay? i.e. When your car shows 70 mph, what speed does TomTom on the iPhone show?

    If your TomTom app indicates speed correctly but incorrectly when through CarPlay then there may be a configuration setting that wrong on your cars' radio. Have you looked for unit setting such as Miles/kilometres, Map Datum, coordinates type (degrees decimal vs other), etc?

    Sorry, I don't have access to any vehicles that have radio/ICE that has CarPlay. Just thinking of possible solutions.

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