Technical Description: Ground: Diagnostics

The engine will not start if the power ground is missing and the diagnostic tool will not be able to make contact with the system.
The engine will not start if the sensor ground is missing and the throttle will go into limp-home mode. As the two sensor ground outputs are coupled together internally in the throttle body, there will be no symptoms if a break should occur in only one of them.
If the reference ground is missing, diagnostic trouble code P0134 will be generated.