OBDII Connection Refused

[hudiy]

Thanks for the feedback. We are glad to hear the issue has been resolved. Your dashboard looks stunning!

By the way, we recommend updating to the latest version (2.4), where we improved communication with the ELM327. In the previous version (2.2), we also fixed the Phone's Bluetooth connection stability issue that was visible in the logs you provided. Instructions for the updating are available on our GitHub: https://github.com/wiboma/hudiy/blob/ma ... d#updating

Topic about 2.2: viewtopic.php?t=144
Topic about 2.4: viewtopic.php?t=171

[Soup2409]

Thank you will do so keep up the awesome job with Hudiy

[Tommiedw]

Thanks for all the help Hudiy really enjoying the dash and all the custom things we can do! Having some hickups with ELM327, paied it through the Hudiy interface and its also showing OBDII connected at the bottom right. But none of the dashboards are working, I maybe get data once and then nothing (almost like one static read and nothing after that)

What I get from the logs
[2026-03-03 15:34:07.110654] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:07.110802] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:07.110845] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:12.110970] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:12.111051] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:12.111074] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:17.111294] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:17.111379] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:17.111407] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:22.111548] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:22.111637] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:22.111664] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:27.111905] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:27.112101] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:27.112136] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:32.112263] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:32.112486] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:32.112522] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:37.112652] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:37.112728] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:37.112753] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:34:42.112880] [0x00007ffe9a325560] [error] [hudiy] [ObdRfCommTransport] failed to connect, address: AA:BB:CC:11:22:33, channel: 1, error: 16, message: Device or resource busy
[2026-03-03 15:34:42.112962] [0x00007ffe9a325560] [info] [hudiy] [ObdDevice] failed to open obd transport.
[2026-03-03 15:34:42.112990] [0x00007ffe9a325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:43:22.954189] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:43:22.981283] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] read failed, data: +DISC:SUCCESS??
[2026-03-03 15:43:22.981326] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] executing command: ATZ, response read failed
[2026-03-03 15:43:22.981338] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] initialization failed
[2026-03-03 15:43:22.981347] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initialization failed.
[2026-03-03 15:43:22.981355] [0x00007ffe16325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:43:27.981453] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:43:27.981546] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] read failed, data: IRABLE?
[2026-03-03 15:43:27.981561] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] executing command: ATZ, response read failed
[2026-03-03 15:43:27.981572] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] initialization failed
[2026-03-03 15:43:27.981580] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initialization failed.
[2026-03-03 15:43:27.981587] [0x00007ffe16325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:43:32.981679] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:43:32.981775] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] read failed, data: +CONNECTING<<88:A?
[2026-03-03 15:43:32.981792] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] executing command: ATZ, response read failed
[2026-03-03 15:43:32.981803] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] initialization failed
[2026-03-03 15:43:32.981812] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initialization failed.
[2026-03-03 15:43:32.981820] [0x00007ffe16325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:43:37.981914] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:43:37.982027] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] read failed, data: NNECTED?
[2026-03-03 15:43:37.982046] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] executing command: ATZ, response read failed
[2026-03-03 15:43:37.982078] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] initialization failed
[2026-03-03 15:43:37.982090] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initialization failed.
[2026-03-03 15:43:37.982100] [0x00007ffe16325560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:43:42.982200] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:43:43.833778] [0x00007ffe16325560] [debug] [hudiy] [ObdDevice] initialization done
[2026-03-03 15:43:43.833853] [0x00007ffe16325560] [info] [hudiy] [ObdDevice] activated.
[2026-03-03 15:43:43.833871] [0x00007ffe16325560] [info] [hudiy] [ObdManager] device opened.
[2026-03-03 15:47:11.211548] [0x00007ffe64885560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:47:11.246162] [0x00007ffe64885560] [error] [hudiy] [ObdDevice] read failed, data: +DISC:SUCCESS??
[2026-03-03 15:47:11.246177] [0x00007ffe64885560] [info] [hudiy] [ObdDevice] executing command: ATZ, response read failed
[2026-03-03 15:47:11.246184] [0x00007ffe64885560] [error] [hudiy] [ObdDevice] initialization failed
[2026-03-03 15:47:11.246190] [0x00007ffe64885560] [info] [hudiy] [ObdDevice] initialization failed.
[2026-03-03 15:47:11.246195] [0x00007ffe64885560] [info] [hudiy] [ObdManager] opening device failed. Retrying...
[2026-03-03 15:47:16.246274] [0x00007ffe64885560] [info] [hudiy] [ObdDevice] initializing
[2026-03-03 15:47:16.246368] [0x00007ffe64885560] [error] [hudiy] [ObdDevice] read failed, data: IRABLE?
[2026-03-03 15:47:16.246384] [0x00007ffe64885560] [info] [hudiy] [ObdDevice] executing command: ATZ, response read failed
[2026-03-03 15:47:16.246391] [0x00007ffe64885560] [error] [hudiy] [ObdDevice] initialization failed
[2026-03-03 15:47:16.246396] [0x00007ffe64885560] [info] [hudiy] [ObdDevice] initialization failed.
[2026-03-03 15:47:16.246400] [0x00007ffe64885560] [info] [hudiy] [ObdManager] opening device failed. Retrying...

When running sdptool records AA:BB:CC:11:22:33 I get

Service Name: Port
Service RecHandle: 0x10001
Service Class ID List:
"Serial Port" (0x1101)
Protocol Descriptor List:
"L2CAP" (0x0100)
"RFCOMM" (0x0003)
Channel: 1

then it just follows with Service RecHandle: 0xffffffff

This is what is configured in my main file
"obd" : {
"deviceType" : "RFCOMM",
"serialDescriptor" : "",
"baudrate" : 115200,
"rfcommAddress" : "AA:BB:CC:11:22:33",
"rfcommChannel" : 1,
"maxInvalidResponseCount" : 20,
"startupSequence" : [
"ATZ",
"ATE0",
"ATS0",
"ATL0",
"ATH0",
"ATSP0"
]
},

[Tommiedw]

[2026-03-03 15:43:32.981775] [0x00007ffe16325560] [error] [hudiy] [ObdDevice] read failed, data: +CONNECTING<<88:A?

From what I can gather.

If I run :
sudo rfcomm bind /dev/rfcomm0 AA:BB:CC:11:22:33 1
screen /dev/rfcomm0 9600

I get random text like +CONNECTING<<88:A? or NNECTED? or IRABLE? before entering any text

If I run ATZ to do the reset I get the ELM327 v1.5 but the weird text this shows in between.

So not sure if Hudiy isn't getting incorrect data feedback?

Could it be that the AT resoponses are not clean / clear enough for Hudiy to read it...

[hudiy]

The responses from ELM327 look corrupted. We can't find anything related to them in the docs https://cdn.sparkfun.com/assets/learn_t ... M327DS.pdf

The only thing mentioned in the docs is '?' which indicates response for an unknown command (everything before '?' seems to be a command executed from somewhere). It looks like something else (except Hudiy) connects to the ELM327 and send some data to it. It might be some other device paired with your ELM327.

[Tommiedw]

I tried making sure everything is off and not connected to the ELM327, also tried connecting the OBD to my phone again and I get perfect stats on Torque Pro with realtime data no problem.

Adapater stats on Torque pro doesn't even pick up any errors. So really not sure why I'm not getting any data in Raspbian...

[hudiy]

Did you install or use ModemManager on your system? Did you install any additional software (e.g., via apt) for e. g. Bluetooth?

The suspicious part is the error: "Device or resource busy". It indicates that something else in the system is trying to use this device at the moment. Looking at the AT commands the ELM327 responds with (+CONNECTING, +(PAIR)ABLE), these look like commands from an HC-05 Bluetooth module. Either they are leaking directly from the ELM327 (we haven't encountered a module that responds this way yet), or something from the system is sending them to the module.

https://s3-sa-east-1.amazonaws.com/robo ... andSet.pdf

Just in case, try to disable ModemManager using

Code: Select all

sudo systemctl stop ModemManager
sudo systemctl disable ModemManager

commands.

[Tommiedw]

Thanks for the suggestions, I did check ModemManager and it was disabled. I think its a faulty ELM327 in my opinion, they aren't very expensive. So I'm just going to get a new one and try again.