Testing an ELM327 clone for SAE J1850 VPW output
Reports of Chinese copies of the ELM327 not actually implementing the SAE J1850 VPW protocol can be readily found. Some have opened up their adapters to find pin 2 of the OBD connector not even connected. Here I use a serial terminal to test the output of an ELM327 copy for presence of a voltage output on pin 2 during a simple J1850 message. I have set the ELM to use protocol #2, SAE J1850 VPW, and I have a multimeter attached to ground and pin #2 of the OBD adapter. The meter is set to 2000 millivolts DC. The voltage can be seen to increase during the sending of the message.
While this does not prove operability it at least proves there is some connection internally and at the least suggests the device supports the J1850 protocol.
