i have a 2007 saturn ion 3 with a 2.2 l engine. so the story is i was driving and all of the sudden a yellow light came on. it wasnt the normal check engine light it was one with a arrow pointing down to the engine flashing. when this came on the engine while idling real rough and running rich. i turned the car off looked at the code it threw and it was a p0651: Sensor reference voltage circuit open. i cleared the code and tried to start the car again and it is doing the same rough idle. when ever i turn the key on the code reappears. i went thorugh and check things that get the 5v reference signal. the ones i check that have it are: Camshaft position sensor, air injection solenoid, manifold absolute pressure sensor. i checked the throttle body 5v reference signal and it is missing the signal going to the harness. from here i dont know what else to do.