Feb 262012
 

ELM 327 Bluetooth OBD2 Adapter

Just purchased a 2012 Prius V (why have I not written about that yet?) and one of the more active topics on the PriusChat forums is how to disable the annoying backup beep that sounds continuously while you are in reverse. Now, you might think that a backup beep is a great feature. Only problem is this beep is very loud and is only inside the car! It cannot be heard by those behind you as you would expect.

In the previous Prius incarnations you could hold your tongue a certain way and press a series of dash buttons along with your key fob to disable this ‘safety’ feature. Now, Toyota says to take it to your local dealer for them to make the change. Only problem is many dealers don’t even know it can be done (or at least the people you and I would talk to don’t) and many new owners report that the dealer wants to charge anywhere from $50 to $100 to do a 2 minute job. Some dealers do the right thing and turn it off free of charge but some only do it after the owner called Toyota corporate and complained.

Me, I know my dealership would do it if I asked but why have them do something that I can waste hours figuring out for myself. First, I needed a way to talk to the car’s computer. I had already bought ELM 327 Bluetooth OBD2 scan tool from Amazon that plugs into the ODB-II slot under the dash so I could monitor some of this little hybrid’s inner workings (here is another post I should have written). The device uses bluetooth to communicate to the outside world and wouldn’t you know it, a number of Android apps have been written to accommodate. (Note: Seems that the OBD2 port has a constant power supply, so even if you turn the car off the device stays on as does the Bluetooth, so probably best not to leave it plugged into the car overnight any more than you would leave your dome light on.)

Seemed like this little scan tool should be able to send data as well as receive, so now I just had to figure out how. I tried using the android ‘Torque’ app that I was using to monitor the vehicle but had no luck then I remember I had seen a program called ‘ELM 327 Terminal‘ which claimed to allow you to communicate with the ELM 327 adapter, sending commands to your hearts content. My first attempts to just send the strings I had seen in the forums did not work. Then I ran across a post explaining how to send these commands to a USB connected ELM327 device using a laptop and a terminal program and figured the same commands should work with the ELM 327 Terminal Android app as well.

Out to the car. Plugged in the ELM327 device. Activated Bluetooth on my phone and told the terminal program to ‘connect’. I had the terminal program send a AT I command just to make sure I was communicating with the device. Now I crossed my fingers and hoped for the best. I turned ‘Timer’ (right side of screen above ‘clear’) off otherwise the command you send gets sent over and over again. (Not sure it matters but in case it does, I had the car ‘on’ with the ‘Ready’ light showing and all the doors were closed.)

First we need to tell ELM327 where to direct our commands, in this case we want to talk to ECU (engine control unit?) 7C0, the combination meter.


Type: AT SH 7c0 (hit ‘Send’)
Returns: OK

Type: 21ac (hit ‘Send’)
Returns: 61 AC 00 (00 means continuous reverse beep)

Type: 3bac40 (hit ‘Send’)
Returns: 7F 3B 78 (no idea :)
Returns: 7B AC (meaning done)

Type: 21ac (hit ‘Send’)
Returns: 61 AC 40 (40 means only a single beep now)


Now for the real test, I popped the Prius into ‘Reverse’ and joy! joy! only 1 beep. Guess now I will have to figure out what other options I want to configure.

  42 Responses to “Programming a Prius to Disable the Backup Beep”

  1. How to set it back to continuous reverse beep

  2. Instead of 3bac40 send 3bac00

  3. Prius V 2012. Works exactly as described. Thanks.

  4. Where did you get a list of commands to send to change the settings? is there a list of them somewhere to download. That way can change other settings?

  5. Worked like a charm! Thank!!

  6. On my V2, OBD2 never returns an OK. For every command, I get the response “ELM327 V1.5″ and the reverse beep is still continuous. Any thoughts? Thanks.

  7. Worked like a charm in 2013 Prius V Five. Thank you!

    When using ELM327 Terminal, need to make sure to type in the command in the small box at the bottom left, and not on the larger box.

    • Hector, Thanks for the clarification. I have not had a chance to play with any programming since I wrote this article. Would love to find some more things to ‘fix’ :)

  8. Thanks! Bought a $12 ELM 327 adapter from Amazon and followed your instructions. Worked great on my 2012 Prius III. Now if only a had a similar proceedure for the seatbelt beep….

  9. In the elm 327 terminal you need to type in the small box in the bottom left of the screen. If you type in the big whit area above where it keeps showing elm327 v1.5 it is not actually sending a command. The directions worked for my 2010 base model Prius!

  10. Worked on my 2010 Prius IV. Thanks a lot. Perfect instructions.

  11. Thank you! Worked great in my ’13 Prius III. The terminal program was a little buggy but it worked.

  12. Is there an option for one short beep in reverse, or is it one long, continuous tone as long as the car is in reverse?

  13. Any possibility to disable the lockout on the navigation map. Above 4 or 5 mph, it locks so that no additional input other than a very limited number of commands such as stop navigating.

  14. LOVE IT! I’m finally beep free!!! thanks!

  15. now if I could only switch from Fahrenheit to Celsius….

  16. One more to confirm that this works perfectly (I have a 2010 Prius base model). Such a greater pleasure to drive it now- and to think, the service guy at my dealer told me that this couldn’t be done. Can’t wait to show him that I knew better! Now, on to discovering how to disable that seat belt beep…

  17. PLEEEEEEASE let me know if you get the navigation/DVD player lockout with this as i don’t want to mess with any wiring to do the bypass…

  18. Just turned off the beep in our 2013 Prius – now it just beeps once when we put it in Reverse. Thank you SO much!

  19. Thanks for posting this how-to. I just tried it using OBD Car Doctor app and a BAFX OBDII adapter I got on Amazon for about $20 (couldn’t get the ELM 327 terminal app to work, but the Car Doctor console feature worked fine).

    Now beep-free (well, one beep I can live with). This was a lot cheaper than paying $80 at the dealer. Best, Terry

  20. My problem was I wasn’t connected to the program or the bluetooth wasn’t connected. I saw the option on the lower part of the screen to connect. The send button went white, I was able to type in the commands in the lower left small box, hit send 4 times, and WOW it worked. Now only one beep instead of that annoying series of beeps. Thanks so much for your help. Can’t wait to see my wife’s reaction when she backs out of the garage in the morning haven’t told her. It bothered her more then me. Thanks again. Greg

  21. Hi Gary,

    Thank for your guide, unfortunately on the 2013 Prius V I get more characters than “61 AC 00″. This makes me worried about what I’m doing.

    Can you post any reference material on what each code means? I’d feel a lot more comfortable if the instructions included what each code means.

    Thanks!

  22. hey i have obd2 adaptor. can i connect through iphone??

  23. when i try to connect to adaptor through samsung S3 it says “java.io.IOexception:Permission denied” and SEND button is still white what should i do??

  24. Yes, confirmed this works. Did this on my 2010 Prius 2 using the same OBD2 Diagnostic Interface on my Motorola Droid.

    Now, how to disable the annoying seatbelt beep? I always pull in my neighborhood within 100 feet and pop my seatbelt off, its annoying to have to keep it on everytime i pull in back to the garage.

    Does anyone have instructions on how to disable seatbelt beeping for Driver and Passenger?

  25. Hi. I bought the same elm 327 connector as you. However, I am unable to connect when I type in 21ac. Any idea why?

    When I type in at sh 7c0, it returns with ok. But when I type 21ac I get an “unable to connect error”. Because of this I cannot program my 2010 prius seat belt beeping to a single beep

  26. Gary’s instructions allowed me to turn off the hated seat belt chime and the reverse chime using the elm 327 and the free elm 327 terminal. Thanks Gary. Now what I want is a list of Prius specific CAN codes to tweak other settings. ie. My headlights when on auto do not turn on soon enough, (it’s really dark before they come on). Does anyone have the code for that?

    • On page 593 of the manual, there is a section that talks about the Light sensor sensitivity, but if you do not have a Navigation or Display that may have to be modified through a code like with reverse beeper, which is probably what you meant in your post.

  27. I’m thinking about trying this but worried about possible “extra codes.” Wondering if you ever resolved your question or felt reassured that you hadn’t inadvertently reprogrammed other features… Thx!

  28. Re the extra codes comment I just submitted – I was intending to direct it to Bob Smith (comment #22)

  29. Has anyone tried this with an Iphone 5?

  30. Thanks a lot Gary for this super process description . Makes me saving 70€ ( 100$ , I’m from France ) Thanks to Hector for the “small box” tip . Fyi, My Prius 3 dated from Nov 2009.

  31. Thanks for the wonderful process description. Worked perfectly on my 2012 Prius IV.

  32. Thank you so much!

  33. Just wanted to let you know that this post inspired me a few months ago to include Toyota settings (such as this reverse beep) in my own Android app… which I’ve just released. It’s called Carista. Basically, it provides a UI for the same kind of commands that you’ve described here. So no need for a terminal! Thanks for this information in the first place :)

  34. Hi!

    So… I read the initial post… and was going to say that there’s an app for Android called Carista that has a bunch of parameters that can be programmed… including the Reverse Beep… But I see that the author has beaten me to it. :) Now, given that the procedure for the reverse beep is described here and can be done with a simple terminal, it would be cool that this one was included for FREE in Carista (as a demo of what can be done, to encourage others to pay for the other options).

    What I would love to be able to do is configure the automatic turn on of the main car lights when I turn on the car (it’s now mandatory in Switzerland to drive with lights on, so I would like to make them turn on automatically). :)

    Gilles.

  35. About to try the instruction on disabling the reverse continuous beep… Any instruction on getting rid of the seat belt beep?

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