Conditions for Running the DTC

WARNING: This page is about a different car, the 2004 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

DTC P1518 is not set.
The ignition switch is in the crank or the run position.
The ignition voltage is greater than 5.23 volts.
The TAC system is not in the battery saver mode.