Conditions for Setting 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.
The PCM does not detect a change in the left/primary fuel level of at least 4.0L (1.1 gal) over a distance of 241 km (150 miles) or 40 min.