Conditions for Running the DTC

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

The engine is running.
The vehicle speed is less than 5 km/h (3.1 mph).
OR
The engine is running.
The vehicle speed is between 30-70 km/h (19-43 mph).
DTC P1391 runs continuously once the above conditions are met.