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 is running.
The vehicle speed is 0 km/h (0 mph).
The ignition voltage is between 9-18 volts.
The transfer pump is activated.
A slosh delay of 20 seconds has passed.
DTC P2636 runs continuously when the above conditions are met.