The 2020 through 2022 GMC Sierra 1500, the 2020 through 2022 GMC Sierra HD, the 2021 GMC Yukon, and the 2021 GMC Yukon XL are among the brand’s models included in a massive new General Motors recall. This problem relates to the transmission control module and is capable of causing momentary rear wheel lock-up and a possible crash.
Only diesel-engine configurations of the GMC Sierra and GMC Yukon are included in GM Safety Recall number N242454440 because of the specific transmission these vehicles were built with. Gasoline models are unaffected by the issue.
The problem:Â GMC Sierra, Yukon, and Yukon XL units with Duramax diesel engines and the associated transmissions have a transmission control valve subject to excess wear and a transmission control module whose software is unable to detect loss of pressure in the valve resulting from this problem.
The hazards:Â as the transmission control valve wears at an accelerated rate, the transmission will gradually lose pressure. With the stock software unable to detect this, shifting will become harsher over time. Once the valve reaches a certain point of wear, it becomes susceptible to failure when the transmission downshifts from eighth gear.
When the GMC Sierra or GMC Yukon transmission control valve fails, this can cause lock-up of the truck’s or SUV’s rear wheels. With the vehicle in motion, this momentary lock-up can boost the risk of an accident, crash or collision.
The fix:Â installation of new transmission control module software is instructed by GM as the step dealer service personnel should take. The new software makes the module able to sense the excessive valve wear occurring approximately 10,000 miles before it becomes severe enough to cause valve failure and rear wheel lock-up.
When the reprogrammed module detects a critical level of valve wear, the software prevents the transmission from shifting higher than fifth gear, indicated by a “reduced propulsion” warning on the instrument cluster. The “service engine” light will also illuminate. The rear-wheel lock-up cannot occur with eighth gear inaccessible. GM will release a special coverage program to repair transmissions affected by a defective control valve, as detected by the newly installed software. However, at the time of this writing, no parts are available for the transmission fix.
A stop-delivery also applies to all GMC Sierra and GMC Yukon units currently in dealership inventory. Used vehicles that are in the GM Certified Pre-Owned (CPO) program are immediately decertified if included in the recall.
Affected components: transmission control module software.
Affected vehicles:Â
- 2020 Chevy Silverado 1500
- 2021 Chevy Silverado 1500
- 2022 Chevy Silverado 1500
- 2020 Chevy Silverado HD
- 2021 Chevy Silverado HD
- 2021 Chevy Suburban
- 2021 Chevy Tahoe
- 2020 GMC Sierra 1500
- 2021 GMC Sierra 1500
- 2022 GMC Sierra 1500
- 2020 GMC Sierra HD
- 2021 GMC Sierra HD
- 2021 GMC Yukon
- 2021 GMC Yukon XL
- 2021 Cadillac Escalade
- 2021 Cadillac Escalade ESV
Number of affected vehicles: the GMC Sierra has the second largest number of affected units in the recall out of the 461,839 Chevrolet, GMC, and Cadillac vehicles involved in the United States. Among these, 80,033 units of the GMC Sierra 1500 pickup and 135,323 units of the GMC Sierra HD pickup have been recalled.
Among Big Red’s sport-utility models, 2,980 GMC Yukon and 2,162 GMC Yukon XL SUVs are affected as well.
Another 52,220 units across all brands and nameplates are involved in Canada.
Owners should:Â read the special instructions contained in notification letters from General Motors before responding to the recall. These letters will be mailed on Monday, December 9th, 2024 to all owners of GMC Sierra and GMC Yukon diesel vehicles included in the recall.
The Sierra and Yukon units involved will be inspected and, eventually, fixed by GM dealerships free of charge to the owner. Some owners may qualify for courtesy transportation while awaiting the remedy, if the truck or SUV is still in warranty.
People who want more information about the recall have the option of reaching out to GMC customer service using their standard toll-free phone, mentioning the recall number as appropriate:
Contacts:
- GM recall number: N242454440
- GMC Customer Service: 1-800-333-4223
Comments
How about an upgraded TCV ! This makes more more sense than a TCM reflash ??
Right! It sounds like an early warning system that tells you that your transmission is going to fail early.
Ford has JUST started to get their recall situation under control so I guess GM felt like SOMEONE has to keep doing them 😆
I for one am not waiting for this problem to manifest itself, nor do I think the GM “solution” is really doing anything besides prevention the vehicle owner from using all 10 forward gears. I am opting to incur the expense myself and doing what GM should have done years ago and fixing the TCV for good with an aftermarket solution. Frustrating, but this is what we are dealing with.
What i learned from the article was that the transmission cont valve wears at an excellerated rate and GM is just putting a band-aid repro to cover it up untill complete failure is indicated when your CEL illuminates.
(out of)Control Module .
Those are relatively new trucks with most having much less than 100k miles and the control valves are already wearing out?! Oh wait, it’s the junk 8-speed transmission.
GM used to build good solid automatic transmissions. Their 2 speed Power Glides, 3 speed Turbo Hydromatics, 4 speed OD’s, and even the 6 speeds have all been reliable and long lived (never had one fail). Not sure what the problem is and I sure hope the 10 speeds hold up.
3 days old news
Don’t buy one with the 6l-90 transmission, pure garbage and they kno it just like Ford and there garbage. Mine went out at 130 k and cost me $4500 to repair with heavier duty kit, trans guy told me he gets them all the time at 60, 70 and 8o k said I was lucky to get 130k, totally unacceptable!
Alison should be ashamed of using their name on this tranny.
THEY look you in the eye with a SMILE and TAKE our money THEY will say thank you .
This is America!!! Stop making JUNK! No wonder we’re behind in world industries
But I will say, don’t get your hopes up if you take it to the dealership, because me and my husband took his truck in July 13th. It is still in the shop, waiting for a transmission valve. And we still don’t know when it’s coming in.Because that’s what they told me today. 5 whole months it’s been in there, and it’s probably gonna be in there longer because we still don’t know when it’s coming in.
He has a Sierra 1500.