TCU and hondalink

Discussion in 'Clarity' started by Alex800st, Mar 9, 2020.

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  1. Alex800st

    Alex800st Active Member

    What is TCU stands for?
    Why my hondalink reports charging status from the car, but I can not send any command to the car like "turn on climate" or "stop charge" - it give some me a message "unable to receive a response from the vehicle"?
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  3. Paddy

    Paddy Member

    Try restarting your infotainment unit. It fixed the same problem for me a few times.
  4. Cash Traylor

    Cash Traylor Active Member

    For our Clarity vehicles it specifically refers to the Telematics Control Unit which manages your charging timer if one is set. It also shows a signal strength of the 3G data connection your car uses to talk to the Honda servers for your remote Honda Link app to work. If it shows no bars then that might be part of the problem with your phone connecting as the AT&T data connection Honda has for your car to talk to their servers is out of range or not working for another reason.

    You do not have a timer set which is why your dash is displaying TCU Timer Off. If you set a charging start time, then even if the car is plugged in it will not start charging until that time and will stop once charging is complete or at a "stop" time set.

    To restart your tablet, push and hold the Audio Power "button" for about 5-8 seconds until it prompts to reboot and select yes. Keep your car powered on until it has rebooted. You can set your head unit to reboot every night if you wish (called a Memory Refresh) and set a time to do that when it is unlikely you will be driving. If you never see bars next to the antenna on the TCU dash display then that may be a problem with your parking location, or something else (similar to your phone being out of carrier range). You can also get odd behavior also similar to a weak carrier connection like being able to receive a text message but unable to send. So your car can send out the charging status, but it is unable to receive messages like start, stop, and climate etc.

    See your manual or the app on timer operation, pages attached.
    Screen Shot 2018-01-18 at 3.59.06 PM.png



    Attached Files:

    Last edited: Mar 9, 2020
    Mowcowbell, Alex800st and Pegsie like this.
  5. Alex800st

    Alex800st Active Member

    Thank you, restarted, but no luck :(
    TCU always shows 4 or 5 out of 5 bars when I shut down the car (we do not have AT&T here, so I guess it uses some other carrier.)
    Guess will have to visit a dealer.

    BTW is there a way to read IMEI out of the car?
  6. Cash Traylor

    Cash Traylor Active Member

    Yes, but you have to hack the headunit with HH as far as I know.
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  8. Alex800st

    Alex800st Active Member

    I was at a dealership almost all day.
    First we called Honda to open a case (SA said it is necessary so they get paid).
    CSR from Honda said that TCU unit had to be upgraded, she mentioned a specific version that I had, and a new one.
    Then several hours tech was trying to upgrade the unit, being on the phone with different Honda departments.
    After that he gave up, said that I will have to come back when they either figure out how s-t works, or get Honda engineer onsite.
    Not impressed, but at least I know why it does not work.

    If anybody knows a dealership around Toronto who knows how to deal with Clarities - please let me know.
  9. Cash Traylor

    Cash Traylor Active Member

    Um, what year is your car? I am not aware of any service letter for the clarity TCU... And I think they have no clue what they are talking about. I would say that you likely need to rebind your HondaLink phone app with your car first. That can be done all from your phone in the car, maybe a call with Honda - no dealership. The Hondalink TCU function is pretty fleet wide and not really a Clarity-ism. However I think you got the "level one tech support" where they try "so did you try rebooting your computer?" Maybe someone on the thread can give some input about a TCU software upgrade, however unlike a lot of Honda cars, as far as I know the Clarity is still almost completely assembled in Japan and shipped here. Therefore the base firmware level for all the components that go in them is whatever the current level is at the factory. Unlike cars assembled in Mexico, the US etc, where a lot of components can come from off the shelf stock from common inventory. Curious....

    Good luck,

  10. Alex800st

    Alex800st Active Member

    Mine is 2020.
    Anybody in Canada - what year is you Clarity and can you send a remote command to it?
    How do I “unpair” the app from the car?
  11. Cash Traylor

    Cash Traylor Active Member

    You log out of the app, and then create a new log in (new user name and password for the Honda Account). You may need to call honda tech support to have them deactivate your existing user account to be able to assign your VIN to the new account. The big trick is to log in and pair your VIN with a "new user account."


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  13. Cash Traylor

    Cash Traylor Active Member


    Ok, hold on. Your dealer experience has been bothering me. I really don't think this is the case, couldn't be, however I really hope they were not trying to update the software on your "non-existent Transmission Control Unit" (TCU).... I doubt it, but man we have heard of some bone head things dealers do around these cars. They often cannot even spell PHEV yet...

    However, the above aside, I wanted to test this, and then give you something to try. You can bypass the Cellular communication route side of the TCU (sorta) with HondaLink and test and see if your car can communicate with your app correctly first (or after your re-bind). You have to give your car a way to access the internet. It CANNOT be through your phone that you are using to HondaLink with (and bluetooth must be off on your hondalink phone).

    So, if you have WIFI at your house where you park you can use that, or another non-hondalink phone as a hotspot. You need to set your Infotainment system to connect to an available hotspot with internet. You need to confirm it is working but making sure it is not using hondalink through your phone (turn your phone off) first. So connect it to wifi, then use the hondalink on the infotainment system to do something that requires internet (hondalink weather, places search, use the web browser, internet radio, etc.) whatever to make sure that your car is online through wifi. You can then turn your phone on and connect to the same WiFi (again your car cannot be connected to your hondalink phone as a wifi hotspot) so you are on the same network.

    See if you can perform Hondalink functions from your phone then (turn it back on, bluetooth off, put it in airplane mode but turn wifi on and connect to your house or that common hotspot your car is on). If it works, then turn your phones cell connection back on, and it's wifi connection off. Then try again (this lets you know if your car can still communicate via the wifi, and that your phone's hondalink still works over your cell data connection.

    The car connection will try to use the internet wifi hotspot first (you should not have to have your car on, it should be listening through wifi). If it can talk to Honda's servers through WiFi it generally does not bother using the 3G. So, that would let you know if it is the 3G connection through the TCU or if it is your actual HondaLink server connection in general (Honda's hosted servers and the way your car is registered with them).

    Sorry if that was confusing, but hopefully you got the idea. Kind of like how your phone will "prefer" to use a WiFi hotspot internet connection over the 4G cellular internet if the WiFi is available and on. Your car always has a passive internet connection to any hotspot it has been allowed to connect to in range.

    Let me know if this has any diagnostic value for you. I am sorry it is a long post, should have made it a step by step. I'm tired and wanted to get this to you before I called it a night.

    Good luck,

    Last edited: Mar 12, 2020
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  14. Alex800st

    Alex800st Active Member

    Did some tests, here are results.
    Tested that car is connected to home wifi, can check the weather (I have no browser for some reason). Can see the car on my home router and can ping it (also tried to telnet, ssh and browse into it just for fun, no luck btw (would be nice to see some linux prompt, eh :)

    Still commands do not get passed to the car, with my phone on the same wifi or on cell.

    I do not believe that the car can use wifi for telematics, only cell.

    Another thing - as soon as car is off, its wifi connection also off (pings disappear).

    Called another dealership, it was a surprise for them that hondalink exists.

    Do not want to re-create a Honda account yet, as we have an active case with Honda to troubleshoot.

    Life sucks and then you die.
  15. Cash Traylor

    Cash Traylor Active Member

    Yeah, the only ports are 5000 and 5500. Hondalink will work through WiFi, I confirmed it by disabling the 3G connection on my car and using Hondalink on my android phone through WiFi on with cell service and bluetooth disabled. However, sounds like you have your hands full trying to get support up there. Good luck! I had really hoped that 2 years into this Honda Dealers would get their act together. I know in Texas we have a "franchise" rule where car dealership must operate through licensed dealerships not manufacturers (which is actually fine, works great 99% of the time) but it means that there are no "factory stores" (with Honda there wouldn't be anyway so moot point). However, I have wondered in this case if manufacture trained dealerships would have handled the Clarity better. Makes me wonder about how it works in other areas where the rules may be different. However, I guess considering the reports on this forum, it does not make any difference even if there are different location rules.

    Good luck!
  16. Alex800st

    Alex800st Active Member

    How can I disable 3G in the car?
  17. Cash Traylor

    Cash Traylor Active Member

    You would have to hack the headunit, root it, and then look up a few things I cannot post publicly but are available on the internet elsewhere. There are also secondary methods if you have the correct equipment. There is no "user option" if that is what you are asking.
  18. Alex800st

    Alex800st Active Member

    Honda Canada called me back. The guy said they were able to re-create the issue (they've asked for my login/password info several days ago) and that problem is on their side, and ticket was escalated to engineering.
    Is there anybody in Canada who can send commands to the car like turn on climate? WHat year is your Clarity?
    The guy could not confirm is it a problem only for me or for everybody.
  19. insightman

    insightman Well-Known Member Subscriber

    It's amazing how often "engineering" has to provide a fix to get just one Clarity's Hondalink software working. Sometimes I wonder if Honda has a different version of the Hondalink software installed in each Clarity manufactured.
  20. Cash Traylor

    Cash Traylor Active Member

    They have something configured incorrectly on there servers for your vehicle. The commands are coming in from your vehicle (status) but when you send commands for your vehicle to their servers they are getting routed wrong. I had the exact same issue but was getting different errors (hondalink app has been upgraded several times since then), and the fix was to create a new profile (rebind) to my car. It generally happens if the VIN is encoded wrong against your vehicles TCU transponder. If they cannot fix it you may go into your infotainment diagnostics and use the lower option to view vehicle status. There you can confirm that the VIN encoded in your headunit agrees with your actual vehicle's VIN number. Not diagnostic because you can't change it there anyway but if wrong - a Honda service center can. I doubt that is the issue, they have HondaLink server config issues often... just check the reviews...


    Last edited: Mar 17, 2020
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  21. Alex800st

    Alex800st Active Member

    How do I go there?
  22. Alex800st

    Alex800st Active Member

    Thank you!
    In my case "Vehicle status" shows:
    Current received VIN: 00------
    Initial registered VIN: 7 digit number, starts with 10800xxx
    Last registered VIN: [nothing, empty]

    In that 7 digit number last 6 digit matching last 6 digit of the actual VIN printed on the door frame, but my actual VIN ends with LC800xxx, not 10800xxx.

    Is it normal or there is the problem?

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