Conditions for Running the DTC

WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Ignition voltage is 7-16 volts.
The APM runs a portion of the diagnostics for this DTC at Accessory/Ignition On.
The APM runs more diagnostics when the 42 volt output is commanded on.