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I recently bought an ELM327 adapter from China and was very satisfied with it. It was working fine with Torque and other OBDII apps for Android, and I could always pair with it using 1234 as the bluetooth PIN code as soon as I plugged it in the car and turned on bluetooth.

After a little more than a month plugging it in after turning on the ignition and removing it after turning off, one day it just refused to accept the 1234 pin code, and since then it never accepted it anymore. I wonder if the bluetooth module might have been somehow reset or its memory corrupted in some way so the current password might have changed, but before I go out the trouble of making a little software to brute force crack the 4 digit pin I'd like to know if anyone ever had the same problem and, if so, whether it was possible to recover from it.

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2 Answers 2

Try giving one of these pin's a try:

0000, 9999, 1234, 2345, 3456, 4567, 5678, 6789, 7890

Alternatively have you tried another phone, or a laptop with bluetooth and the appropriate software? Or even another car?

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Yes Braunson, I have tried some of these and with the adapter on another car and through another phone and computer too, and none worked so far :/ I'd hope there would be some kind of reset procedure, but if I crack open the dongle to access the bluetooth module on top I guess it will probably break anyway. I'm traveling right now, but when I get back I'll try some more codes then I get back here telling if any of them worked. Thanks! –  Claudio May 21 '13 at 17:19
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When this happens it's usually due to the ELM module needing it's firmware reflashed. This involves removing it and reflashing the chip or simply replacing it. You can find more information about this at ftdichip.com they have a lot of DIYs on how to build these modules.

This breakage is very common when buying the cheap China built adapters.

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