Pcm System Ground
WARNING: This page is about a different car, the 2005 Dodge Magnum and 2005 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
The PCM cannot determine a poor system ground. However, one or more diagnostic trouble codes may be generated as a result of this condition. The module should be mounted to the body at all times, including when diagnostics are performed.