Can't get a read from Pontiac Bonneville about arduinoobd

[gmas]

I forgot to mention, the Arduino is getting power from USB, not the OBD board. Not sure if that can be the cause for empty readings..

[WA4OSH]

George,
According to the Dr. Robot wiki page,
http://www.dfrobot.com/wiki/index.php/OBDII_TTL_Adapter
"Supporting CAN bus (used by most modern cars), KWP2000 and ISO9141-2 protocols"

Your Pontiac may be running the SAE J1850 VPW protocol.

There are two ways to check this. Look at the ODB-II connector of your car and see if the pins give you an idea. Read this:
http://www.obdtester.com/obd2_protocols

Another way is to borrow an OBD2 diagnostics tool from a car parts store. O'Reilly's near my house ends their Innova 3100 out for a quick code check. While it does an auto-link, it tells you what protocol it found.