GM released a new Special Coverage bulletin, N262552620, in May 2026 for certain 2021 full-size SUVs with the 3.0L Duramax. It covers failure of the cylinder 2 glow plug for 15 years or 150,000 miles from the original in-service date, whichever comes first, and applies regardless of ownership.

This matters because it expands the same general issue previously addressed on 2020 LM2 pickup trucks under bulletin N232430460, but the new bulletin is for a different vehicle group and model year. Just as important, this is not a recall; it is a special coverage program that gives owners extra protection for a specific condition if it happens.

Which vehicles are included

The new bulletin applies to certain 2021 Cadillac Escalade and Escalade ESV, Chevrolet Tahoe and Suburban, and GMC Yukon and Yukon XL models. GM says dealers must confirm actual involvement through the Applicable Warranties section in Investigate Vehicle History (IVH) or Global Warranty Management before performing repairs.

That means not every 2021 diesel SUV is automatically included just because it has a 3.0 Duramax. VIN verification still matters, and owners should not assume eligibility until the dealer checks the vehicle in GM’s system.

What the new special coverage says

According to bulletin N262552620, the covered condition is a failure of the cylinder 2 glow plug that turns on the check engine light and sets a diagnostic trouble code. The bulletin says dealers are to replace the cylinder 2 glow plug as necessary at no charge to the customer.

The service procedure specifically says vehicles may come in with DTCs P0672, P1339, and/or P06C6, and the repair is allowed only if diagnosis actually leads to replacement of the # 2 glow plug. If the diagnostic path does not support replacing the # 2 glow plug, no additional repair is permitted under this special coverage program.

GM lists part number 24000504 for the glow plug and 55490568 for the throttle body gasket in the new bulletin. The labor ops also show diagnostic-only time when no repair is required and a separate operation for glow plug replacement on cylinder 2.

What a special coverage is

A special coverage is basically an extended warranty policy for a narrowly defined problem on a specific population of vehicles. GM uses it to provide no-charge repairs for a listed condition during an extended time and mileage window, even after standard warranty coverage may have expired.

In this case, the policy does not authorize replacing all glow plugs, does not guarantee repairs for unrelated check engine lights, and does not mean every vehicle with a 3.0 Duramax has the problem. It only applies when the VIN is involved and dealer diagnosis confirms the covered condition.

What a special coverage is not

A special coverage is not a recall. Recall campaigns are tied to safety defects or regulatory noncompliance, while this bulletin is written as an added protection program for a specific component failure condition.

Owners should also notice the language in GM’s sample customer letter: GM tells customers not to take the vehicle to the dealer just because they received the letter unless they believe the vehicle has the condition described. That is very different from a recall, where owners are generally asked to complete the repair campaign whether or not they already have symptoms.

How the new 2021 SUV policy compares with the earlier 2020 truck policy

The earlier bulletin N232430460 covered certain 2020 Chevrolet Silverado 1500 and GMC Sierra 1500 models equipped with the 3.0L LM2 Duramax. GM released that program in January 2024, and reports tied it to about 40,000 U.S. vehicles.gmauthority+2

The new bulletin N262552620 follows the same basic playbook but for certain 2021 full-size SUVs. Both policies focus on the #2 glow plug, both provide 15 years or 150,000 miles of coverage from original in-service date, both allow reimbursement for prior qualifying repairs, and both require VIN confirmation and diagnosis before repair.

Key differences owners should know

The biggest difference is the affected vehicle population. The older program focused on certain 2020 LM2 half-ton pickups, while the new one targets certain 2021 full-size diesel SUVs.

Another notable difference is the repair detail in the bulletin. The new 2021 SUV policy explicitly lists DTC examples and a reimbursement deadline of May 31, 2027, which gives owners a very clear administrative cutoff for previously paid repairs.

The parts listing also changed. The earlier 2020 bulletin listed glow plug part number 55490594 plus throttle body gasket 55490568, while the new 2021 bulletin lists glow plug 24000504 with the same throttle body gasket 55490568.

What owners should do next

Owners of 2021 diesel SUVs should first verify whether their VIN is included, because GM states that only involved vehicles will show this policy in IVH or the Applicable Warranties section. If the check engine light is on and diagnosis points toward cylinder 2 glow plug failure, the dealer can perform the covered repair at no charge.

If the owner already paid for a qualifying repair, reimbursement may be available, but the request must be submitted by May 31, 2027 unless state law provides a longer period. Documentation matters, so repair orders and proof of payment should be kept together before contacting the dealer or GM reimbursement department.

Why this matters for 3.0 Duramax owners

This new bulletin shows GM is continuing to address glow plug # 2 failures with targeted special coverage programs instead of broad recall language. For owners, that means the right move is not panic, but understanding whether the VIN is affected, what symptoms matter, and what the policy actually covers.