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2021 Chevy Silverado, GMC Sierra get less MPG due to worldwide semiconductor shortage


A new 2021 Chevy Silverado 1500 or GMC Sierra 1500 won’t be as fuel efficient as it’s supposed to be, and a worldwide semiconductor shortage is to blame. Here’s what you need to know.

GM confirmed in a recent Reuters article the company will build the 2021 Chevy Silverado 1500, which already gets worse fuel economy than the prior generation, and GMC Sierra 1500 trucks without a fuel economy module due to not having enough semiconductors for their needs.

The fuel economy module helps the truck get 1 MPG better through the Active Fuel Management (AFM) and Dynamic Fuel Management systems found on different Chevy and GMC trucks.

GM says it will build 2021 models through the end of the model year, typically in August/September without these modules. Trucks that will be affected are 5.3-liter V-8 engines with either a 6- or 8-speed automatic transmission. This engine with 6-speed is often found in commercial work trucks while the 8-speed is found throughout its lineup.

With the module, these trucks currently get city/highway fuel economy numbers of 15/21 MPG (2WD), 15/20 MPG (4WD) with the 6-speed. For the  the 8-speed, fuel economy improves to 17/23 MPG (2WD) and 16/22 MPG (4WD).

worldwide semiconductor shortage

Chevy Silverado models with the 5.3L V8 will get less fuel economy throughout the end of 2021 model year. (Photo courtesy Chevrolet)

The reason GM is moving forward without the fuel economy module is to meet the demand of its dealers as well as the currently hot truck market.

“By taking this measure, we are better able to meet the strong customer and dealer demand for our full-size trucks as the industry continues to rebound and strengthen,” GM spokeswoman Michelle Malcho wrote in an email to Reuters.

While the automaker won’t state how many trucks will be affected by the worldwide semiconductor shortage — it’s too early to tell — GM did say those trucks will get 1 MPG less fuel economy without confirming the exact new numbers.

GM has recently added it will offer a $50 credit for those trucks bought without AFM/DFM.

Also, the 2022 Silverado and Sierra won’t have AFM at all, and this issue might still affect 2022 models based on current news reports on the size of the shortage.

What is AFM/DFM?

These, often criticized systems, seamlessly turn off cylinders when the computer determines your driving needs are demanding less fuel.

Basically, if you are coasting or driving on a downhill grade, the truck will automatically go from eight to four cylinders for AFM systems or will turn off a variety of cylinders, even going below four cylinders, with DFM systems. Most owners don’t notice anything when this system is working properly.

Critics of these systems say they use more oil as well as do damage to the engine, and they feel they get better fuel economy without them.

The bottom line on the worldwide semiconductor shortage

By removing the AFM, DFM systems, some fans will rejoice while others will have a big decision to make on whether to buy a new Silverado or Sierra currently on dealer lots — or wait until later in the year to buy one without these systems. While 1 MPG may not make a big difference to some customers, others will want to get everything they paid for in their new truck.

Related Posts:

Worse MPG! 2021 Chevy Silverado 1500 4WD with Duramax sees big drop

Leaked? 2022 Chevy Silverado 1500 engine changes, transmission news

2020 Ram 1500 EcoDiesel 4wd Rated at Whopping 29 MPG!


Tim Esterdahl

Automotive Journalist Tim Esterdahl has been a lover of trucks and SUVs for years. He has covered the industry since 2011 and has pieces in many national magazines and newspapers. In his spare time, he is often found tinkering on his '62 C10 pickup, playing golf, going hunting and hanging out with his wife and kids in Nebraska.

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