Conditions for Running the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The engine speed is greater than 400 RPM.
The ignition voltage is between 9-18 volts.
DTC P3401, P3425, P3441, and P3449 runs continuously when the above conditions are met.