OBD II adapter crash the Car computer (Renault Laguna 2)

[mesobius]

Hi,

my first message seems to be not moderated, so, I try again.

When I plug my OBD II Adapater for arduino, model A (RS TTL) in my OBD Car Connector, Il can get information of Throttle position.

BUT, if I power on my car (not engine start), the Computer car Give me a lot of errors and I can't start the car engine.
If I unplug the OBD adapter I can't start the car too. Errors stil display.

I need to Power Off the car, wait few seconds and restart the car. Then without the OBD II Adapter plug, the car start correctly, without error.

I make many tests, and Each time the adapter is plug in the car connector, the car computer give me deffects.
I have tested with differents protocole initialisation, nothing more.
If the adapter is only plug in car without arduino or PC connection, it's the same.

Is my adapter have a problem ? What's the solution ?

[stanley]

You must turn the car with the key before the OBD-II data can be accessed.

[mesobius]

Hi Thanks for answer,

I had try to plug the OBD adapter on the plug after turn on the car with the key without communication via OBD adpater.
It's the same problem, the computer indicates error in the system and disable the engine start.

Question: if the adpater is plug in the car connector, but no arduino connected to the adapter (so, no communication initiated) is the computer car will work correctly or it may be be distrubed by the adapter ?

[mesobius]

Hi,

due to no answer on this forum about my problem, I have open the OBD adapter to find the solution, because other users seem not having my problem.

as I Said before, there's effectively an hardware problem on the adapter : The resistor R4 WAS NOT SOLDERED CORRECTLY : it was shifted and only soldered on ONE SIDE !

I have re-soldered it correctly and now my car work well with the adapter connected to the car, and without any arduino on the TTL link. the car computer doesn't give me bad warning when started the car.

now I'll try to get OBD information to confirm that's the problem is completly solve. I'll give you feedback after the tests.

Furthermore, I'll just tell you that you can give us answer and way to find a solution, or ask me to send back the product at my first message....

[xload]

Hi,

due to no answer on this forum about my problem, I have open the OBD adapter to find the solution, because other users seem not having my problem.

as I Said before, there's effectively an hardware problem on the adapter : The resistor R4 WAS NOT SOLDERED CORRECTLY : it was shifted and only soldered on ONE SIDE !

I have re-soldered it correctly and now my car work well with the adapter connected to the car, and without any arduino on the TTL link. the car computer doesn't give me bad warning when started the car.

now I'll try to get OBD information to confirm that's the problem is completly solve. I'll give you feedback after the tests.

Furthermore, I'll just tell you that you can give us answer and way to find a solution, or ask me to send back the product at my first message....

Where is R4 localted? I've the same problem with other car.