Action Taken When the DTC Sets: P0402

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0402 is a Type B DTC.
Diesel particulate filter (DPF) regeneration is inhibited.
The ECM commands the engine to operate in Reduced Engine Power mode.
The message center displays Reduced Engine Power.