Conditions For Running The DTC

WARNING: This page is about a different car, the 2003 GMC Sierra and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTCs P0005, P0192, P0193, P0336, P1207, P1432, P1433, or P2665 are not set.
The CNG fuel tank pressure is more than 250 psi (1723 kPa).
The Engine Coolant Temperature (ECT) is more than 68°F (20°C).
The engine speed is more than 100 RPM.
The Mass Airflow (MAF) is less than 200 g/s.