Conditions for Running the DTC

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

Battery voltage must be between 9-16 volts.
Ignition is in the RUN or ON position.
Headlamp switch is in the AUTO position.
High or low beam headlamps must be active.
Vehicle speed greater than 2 mph.
Transmission is in the DRIVE position.