canbus questions/help

[sal_park]

Hi all,

long story short I've had an elm327 canbus reader setup on my car which has been working fine for several months. Then something happened and it stopped working I've gone through everything I can think of, but still can not get it to work. Other devices on the canbus are still working, so I'm pretty sure that's not broken.

I'm looking for any suggestions of what might be causing this - any comments welcome !

This is what I've tried so far:

1) A new ELM327 reader - connected it to the OBDII port to prove the reader works, connect it to the canbus directly, no output
2) Connected an oscilloscope between CAN-H and ground and then between CAN-L and ground. I could see data activity on both CAN--H and CAN-L which was about 2v.
3) Ground connection appears good, about 3 ohms or so between the ELM327 and ground.
4) I could have buggered something up on the config of the ELM327  - I've got a new one in the post to test this thought.
5) swapped CAN-H and CAN-L in case I wired them back to front - still no output.

thanks

sal_park