BMW, ELM327 from Lescars, only working intermittently

[dpocock]

Describe the bug
Purchased a new Lescars ELM327 bluetooth. Installed it in a BMW. It pairs with the app but it only intermittently works. It only works for a few seconds, it downloads the vehicle information and then other functions don't work.

I saw a note in the Lescars ELM327 manual "Certains marques, telles que BMW ou Mercedes, proposent leurs propres applications pour la lecture des données".

There are discussions in the BimmerForums forum where they suggest that ELM327 will never work and it is necessary to use VAG-COM cables. It is not clear if there is any free software solution for VAG-COM.

To Reproduce
Steps to reproduce the behavior: - see above

Expected behavior
Should work every time.

AndrOBD Debug log files
Before I do this, can you please clarify if I am the first person with this problem.

Log detail level
The detail level of the logged debug information can be adjusted in the Settings > Development options > Logging level.

By default the detail level is set to INFO.
Preferred detail level for issue analysis is DEBUG. (Since V1.5.0 this level is called FINE)

Important details on your environment:

• Lineageos
• v2.2.2 from F-Droid
• Lescars ELM327
• BMW

Additional context
Add any other context about the problem here.

[fr3ts0n]

Thanks for your report.

Could you please provide some log files from the connection attempts.
(for details on logging see: https://github.com/fr3ts0n/AndrOBD/wiki/Reporting-improvements---issues)

Have you tried the latest V2.2.4 already?
There have been some improvements in communication to some (slower) ELM adapters.
Maybe your problem is already adressed? ;)

Thx

[dpocock]

I had another look at this today

I updated to AndrOBD v2.3.3 from F-Droid

With the engine stopped, I observe the following:

• I tap the button in the app to connect
• I select the bluetooth ID from the list
• the light on the ELM327 is flashing
• the app says Connecting... and it stays like this for a long time (more than a minute)
• the logs show something like this:

10-11 11:09:55.360 25358 25358 I com.fr3ts0n.prot: OBD Service: 0->9
10-11 11:09:55.547 25358 25455 I com.fr3ts0n.prot: Status change: Undefined->Connecting
10-11 11:10:01.013 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:01.705 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:06.998 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:07.713 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:12.977 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:13.693 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:18.961 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:19.640 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:24.941 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:25.656 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:30.936 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:31.606 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:36.945 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:37.588 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:42.903 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:43.592 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:48.889 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected
10-11 11:10:49.594 25358 25455 I com.fr3ts0n.prot: Status change: Disconnected->Connecting
10-11 11:10:54.873 25358 25455 I com.fr3ts0n.prot: Status change: Connecting->Disconnected

Then I started the engine. With the engine running, I was able to connect immediately. I browsed through the different screens in AndrOBD, looked at the fault codes, etc. It stayed connected for a lot longer than when I tried v2.2.2 in May. Eventually it did lose the connection but I was able to reconnect again immediately. In that case, it would be really useful if it could reconnect automatically without intervention by the user.

[fr3ts0n]

That is what AndrOBD attempts to do when it logs above messages ...

• Somehow this looks like the ECU is not responding to the commubication requests
• If you change to higher LOG level you will see more details
• (for details on logging see: https://github.com/fr3ts0n/AndrOBD/wiki/Reporting-improvements---issues)

[dpocock]

I've sent you a copy of the log by private email

I've tried two different permutations of the device from Lescars:

• ZX-3017-675 (this is the one I was using when I opened the bug report and recorded the log file)
• NX-3014-675 (I got this last week)

They both behave in a similar way, sometimes they lose the connection and try to reconnect many times.

[fr3ts0n]

Here are my notes on analysis of your log file:

Notes:

I see a lot of inconsistencies in your log file and I cannot find any obvious cause to that.

• Adapter responses on ATZ vary
  • seen this on cheap chinese clones
  • Possibly disable ATZ in DEV options
    • will be replaced with ATI in sequence
• Inconsistent response to Mode $01/$09 requests
  • "UNABLETOCONNECT", rx with CAN IDs, rx incomplete, rx clean
  • Inconsistent initialisation of vehicle (CAN) bus?
  • may be related to ATZ issue

My assumption is that your adapters have a timing issue between Bluetooth (Host) and CAN (Vehicle) protocol
I have seen similar behaviour on some cheap ELM clone devices before, especially on vehicle using CAN bus.

Suggestions:

Following workarounds helped most of the other user issues:

• Disable SECURE connection in OBD options (you already do this)
• Disable ATZ command in Development options

[dpocock]

I disabled the ATZ command.

I continue to observe similar problems

With ZX-3017-675 the connection is established and I can see the vehicle info and data screens. After changing between screens a few times, I notice the screens appear blank. Only the header at the top is visible. It is always "Connected" but the data is missing

With NX-3014-675 it is not connecting at all, it gets stuck at "ECU detect..." and I don't see anything else.

Is it possible for the app to detect the bad ELM devices and display a warning?

I can buy a different device if necessary, can you make any suggestions on the good devices to buy? I am in Switzerland, I found these on digitec.ch but I can buy from another supplier or import from Germany or elsewhere if necessary.

[fr3ts0n]

Did you ever try to use AndrOBD with your adapters on another mobile?
That might be even a matter of combination os/phone/adapter/vehicle

I cannot really suggest a special adapter, but I will initiate an issue / community post for users to post their experience with certain adapters / vehicles / mobiles.
I hope this might help you and also others to find a known good solution.

[fr3ts0n]

Please see #187