GM Throttle Body Fix for 2021 GMC Canyon Duramax Diesel

Own a 2021 GMC Canyon Duramax Diesel Unit? There’s a bulletin worth knowing about. General Motors recently issued Special Coverage notice N242445290 for a throttle body problem affecting this popular midsize pickup’s Duramax turbo diesel 2.8L I4 LWN engine. The good news: GM already has a fix ready to go.
The Throttle Body Problem
So what’s actually going wrong with the throttle body? Per the Special Coverage notice, the throttle body motor’s calibration process, which learns the correct throttle position, may not finish successfully within the expected timeframe on affected vehicles.
What does that mean in practice? The throttle body regulates how much air flows into the engine. Its motor has to calibrate itself and learn the minimum and maximum throttle positions every time the truck starts up. When that learning process runs too slowly, drivers can end up with some noticeable problems.

Symptoms of the Throttle Body Issue
If a 2021 GMC Canyon Duramax Diesel Unit is dealing with this throttle body glitch, there are a few telltale signs to watch for:
The Check Engine light may illuminate on the dashboard. This is often the first indicator that something isn’t quite right with the truck.
The truck’s computer may also generate a diagnostic trouble code (DTC). These codes help a mechanic pinpoint the source of the problem once they plug in a scanner.
In some cases, the engine may drop into reduced power mode because of the throttle body issue, and drivers will likely notice a significant hit to acceleration and overall performance.
Anyone seeing these symptoms in a diesel Canyon should get it checked out by a local GMC dealer to confirm whether the throttle body is the culprit.
The Fix: Throttle Body Replacement
The good news is that GM already has a fix for affected trucks. If a Canyon has this issue, the dealership will replace the throttle body at no cost.
Here’s what the repair involves: the technician removes the old throttle body, then installs a new one with two fresh gaskets for a secure seal. GM estimates the whole job takes about an hour, not a bad trade-off for peace of mind.
Worth noting: this repair falls under Special Coverage, which is valid for up to 15 years or 150,000 miles, whichever comes first. So even a non-original owner of the truck is still eligible for the free fix.

What if You Already Paid for the Repair?
What about owners who paid for this repair before the Special Coverage bulletin came out in mid-August 2024? There’s a decent chance they can get that money back.
GM says owners who had the repair done before the Special Coverage announcement are generally eligible for a refund. Keep the repair receipt and any related paperwork on hand, then contact the dealer to start the reimbursement process.
2021 GMC Canyon: Power and Performance
Since the throttle body issue only affects one engine option, it’s worth a quick look at what the 2021 Canyon offers overall as a midsize pickup.
Under the hood, the 2021 Canyon offers two engine choices. The standard option is a 3.6L LGZ V6 gas engine delivering 308 horsepower and 275 pound-feet of torque, paired with an 8-speed automatic transmission.
Drivers who want both torque and fuel efficiency can step up to the Duramax turbodiesel 2.8L LWN I4. It makes 181 horsepower and an impressive 369 pound-feet of torque, which makes it well suited to towing and carrying loads. It pairs with a 6-speed transmission tuned to complement the diesel’s power delivery.
Beyond the engine lineup, the 2021 Canyon also features a boxed frame, an optional 4G LTE Wi-Fi hotspot, and a solid list of driver-assist tech like Forward Collision Alert and Lane Departure Warning. Inside and out, it’s built to handle work duties during the week and leisure trips on the weekend.

Other 2021 GMC Canyon Recalls and Bulletins
Beyond the throttle body problem covered here, 2021 Canyon owners should also keep an eye on a few other recalls and service bulletins GM has issued for this model year.
For instance, there was a recall related to Continental tires on certain 2021 GMC Canyon Duramax Diesel Units, where the tire tread may separate and cause a loss of vehicle control. GM also issued a bulletin about the infotainment system potentially going blank or crashing because of a software glitch.
Staying on top of recalls and service alerts is worth the five minutes it takes. Entering the truck’s 17-digit VIN on the NHTSA website or GM’s owner portal will surface anything open on the vehicle. Catching problems early keeps them from turning into bigger, costlier repairs down the road.
Final Thought
Owners of a 2021 GMC Canyon Duramax Diesel Unit should keep GM’s Special Coverage bulletin N242445290 in mind. If the Check Engine light comes on or the truck loses noticeable power, a trip to the dealership for a throttle body replacement is the next move.
The 2021 Canyon remains a solid choice in the midsize pickup class, especially with the Duramax diesel under the hood. Staying current on recalls and service notifications is what keeps it running smoothly for years.
Questions about a specific truck are best answered by a local GMC dealer or a trusted independent mechanic, who can look at the actual vehicle and confirm what it needs.
Safety note: This guide is for general informational purposes. Brake systems are safety-critical — if you're unsure at any step, or the work requires specialized tools, have it inspected or completed by a qualified technician.
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