Action Taken When the DTC Sets

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The PCM illuminates the service vehicle soon (SVS) lamp when the diagnostic fails.
The malfunction indicator lamp (MIL) remains OFF when DTC P0688 sets.
The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Failure Record buffer.