GM is building and shipping new 2021 Chevy Silverado 1500 and 2021 GMC Sierra 1500 trucks without a fuel-efficiency control module due to a semiconductor shortage. It means that these trucks that are equipped with the 5.3-liter gas V8 engine are rated at one MPG less than they would be otherwise.
Here is a statement from a General Motors spokesperson. “The lack of the active fuel management/dynamic fuel management module means affected models, equipped with the 5.3-liter EcoTec3 V8 engine with both six-speed and eight-speed automatic transmission, will have lower fuel economy by one mile per gallon.” GM spokesperson did not specify how many trucks are affected.
The older 5.3L V8 with AFM (Active Fuel Management) can operate in 4-cylinder or 8-cylinder modes, if this module is installed and enabled. The newer 5.3L V8 with DFM (Dynamic Fuel Management) uses a more sophisticated “skip fire” algorithm to skip a variety of number of cylinder fire cycles depending on power demand.
Does this affect both 2021 Chevy Silverado 1500 and 2021 GMC Sierra 1500 trucks? Yes.
Can the affected trucks be later retrofitted with these AFM/DFM modules to regain the efficiency? No.
How long will this semiconductor shortage affect these trucks? Until the end of the 2021 model year.
We will update this story as soon as we get anything new.