New GM Emissions Recall N242438500: 2024 L5P Duramax SCR Fault Detection

General Motors has launched a new emissions recall that affects certain 2024 Chevrolet Silverado HD and GMC Sierra HD trucks equipped with the 6.6L L5P Duramax.

Recall ID: N242438500

Title: ECM OBD – Selective Catalyst Reduction (SCR) Fault Detection

Release Date: November 2025

Applies To:

• 2024 Chevrolet Silverado 2500HD / 3500HD (L5P 6.6L Duramax)

• 2024 GMC Sierra 2500HD / 3500HD (L5P 6.6L Duramax)

This is a voluntary emissions recall focused on the software that monitors the SCR (NOx) catalyst. There are no parts to replace, but the update is important for emissions compliance and future diagnostics.

What is this recall about?

On certain 2024 L5P trucks, the Engine Control Module (ECM) may not properly:

• Diagnose specific Selective Catalyst Reduction (SCR or NOx catalyst) failures

• Set the appropriate Diagnostic Trouble Codes (DTCs)

• Turn on the Malfunction Indicator Light (MIL) / Check Engine Light when some SCR faults occur

In plain terms: the truck’s on-board emissions diagnostics may not “catch” some SCR problems the way the regulations require. The truck might look like it is fine to the driver even though the SCR system has an issue that should trigger a fault and warning.

Because this is a monitoring/diagnostics issue, GM is handling it as a Voluntary Emission Recall, not a safety recall.

What’s the fix?

The repair is software-only:

• Reprogram the Engine Control Module (ECM)

• Reprogram the Transmission Control Module (TCM)

For certain trucks built prior to August 1, 2023, the bulletin also calls for:

• A barometric pressure sensor reset as an additional programming step

There are no hardware parts listed for replacement. The repair is done through GM’s Service Programming System (SPS) using updated calibrations.

How long does it take?

GM’s labor time guide shows:

• 0.2 hr – If the dealer confirms your modules already have the latest calibration (verification only)

• 0.7 hr – ECM and TCM reprogramming with SPS

• +0.1 hr – Barometric pressure sensor reset where applicable

In real life, expect the truck to be at the dealer longer than the raw labor time. The customer letter estimates about 45 minutes of actual correction time, but scheduling, check-in, and programming queues mean you should plan on leaving the truck for a bit.

Is my truck affected?

GM flags involved vehicles as “Open” for this recall in its internal systems.

As an owner, you can:

• Check your VIN on GM’s recall/owner website for Chevrolet or GMC

• Call your dealer and ask them to look up Recall N242438500 on your VIN

If the recall shows open, schedule the repair. If it does not show, your truck is either not affected or already updated.

Dealer responsibilities (what this means for buyers)

The bulletin lays out very specific responsibilities for dealers:

• All new, used, GM Certified Pre-Owned (CPO), courtesy transportation, shuttle, and CarBravo vehicles affected by this recall must be held and corrected before a customer takes possession.

• Involved vehicles cannot be:

  • Delivered to a retail customer

  • Dealer-traded

  • Sent to auction

  • Used for demo or any other purposeuntil the recall repair is complete.

For CPO units:

• All involved GM Certified Pre-Owned vehicles in the dealer’s SHIFT Digital system will be de-certified until the recall is completed.

• Once the dealer submits a paid warranty transaction in Global Warranty Management, the vehicle can be re-certified and used again for CPO or courtesy programs.

For recent buyers:

• If a dealer sold a vehicle that shows no customer information on the listing, they are instructed to reach out to the buyer directly and arrange the recall repair.

• GM even supplies a sample customer letter in the bulletin for this purpose.

In summary: any time a vehicle subject to this recall enters dealer inventory, the dealer is expected to complete the recall before selling it. And when a truck comes in for service with an open recall, the dealer is expected to inform the customer and make a reasonable effort to complete the recall before releasing the vehicle.

Cost to the owner

GM is very clear on this point:

Dealers are to service all vehicles subject to this recall at no charge to customers, regardless of mileage, age of vehicle, or ownership, from this time forward.

Key owner-facing points:

• No charge for the recall repair

• Applies regardless of:

  • Mileage

  • Vehicle age

  • Number of previous owners

The customer letter also states that eligibility for this service will not be denied solely because your truck has non-GM parts or has had work done outside a GM dealer. That is a big deal for owners with aftermarket parts.

If you encounter any pushback on cost, reference Recall N242438500 and the bulletin language about no-charge repairs.

California owners: Proof of Correction Certificate

For California residents, there is an extra step that matters for registration:

• When a California emissions recall is completed, the GM dealer must provide the owner with a “Proof of Correction Certificate.”

• The California DMV may require this certificate when you renew your registration.

• If the recall is not completed and on record, or if you cannot show the certificate when requested, the DMV may block registration renewal.

In practical terms:

• When you pick up your truck after the recall, make sure you receive and keep the Proof of Correction Certificate.

• Store it with your registration and service records in case the DMV asks for it at renewal time.

(The bulletin notes that dealers can order additional certificates using GM Item Number 1825, but that is dealer-facing information.)

Courtesy transportation

For trucks that are still within the warranty coverage period, the bulletin confirms:

• Courtesy transportation is available for customers whose vehicles are involved in this recall.

Program details follow GM’s normal Service Policies and Procedures Manual, but the important takeaway is that if your truck needs to stay longer than expected, you may qualify for loaner or shuttle options. Ask your service advisor what is available at your specific dealership.

Why you should not ignore this recall

The customer notification letter makes several key points for owners:

• To maintain full protection under the emission warranty, you should have the recall performed as soon as possible.

• Failure to complete the recall can be legally interpreted as lack of proper maintenance.

• Your truck may fail a state or local emissions or smog inspection if this recall is not completed.

• Completing the recall also protects your right to participate in future emissions-related recalls.

For California specifically:

• CARB requires that emission recalls be completed before registration renewal. An uncorrected emissions recall can result in the inability to renew your registration.

In other words, this is not the kind of recall you want to put off until your next big service. It directly affects emissions compliance and possibly your ability to register the truck in the future.

What I would do as an L5P owner

If I owned a 2024 Silverado or Sierra HD with the 6.6L L5P Duramax, here’s the order I would follow:

1. Run a VIN recall check on GM’s site or call the dealer to confirm if N242438500 is open.

2. Schedule the recall as soon as I can, even if the truck is running perfectly. This recall is about detection and compliance, not how it “feels” today.

3. If I live in California, I’d make sure:

   • The dealer gives me a Proof of Correction Certificate at pickup.

   • I file it with my registration paperwork.

4. If I have aftermarket parts, I would:

   • Bring the truck in as-is, since GM’s letter specifically says eligibility will not be denied solely for non-GM parts or non-GM repairs.

5. After the visit, I’d keep the repair order that shows:

   • Recall N242438500 completed

   • ECM/TCM reprogramming performed

That way, if there is ever a question about emissions, smog testing, warranty, or registration, I have documentation ready.

Owner FAQ: Recall N242438500 on 2024 L5P Duramax

Does this recall cost me anything?No. GM states the recall must be completed at no charge to you, regardless of mileage, vehicle age, or ownership history.

Will my truck drive differently after the update?The bulletin focuses on emissions diagnostics and SCR fault detection, not power or drivability. Most owners will not feel any difference in how the truck drives.

I have aftermarket parts. Can I still get the recall done?Yes. The customer letter states that eligibility for this service will not be denied solely because your truck has non-GM parts or work performed outside a GM dealer.

Do I really have to do this?If you skip it, your truck may be considered not properly maintained for emissions warranty purposes, and it may fail a state or local emissions test in the future. Completing it also protects your ability to participate in future emissions-related recalls.

What if I live in California?California requires emission recalls to be completed before registration renewal. When the recall is done, your dealer must give you a Proof of Correction Certificate. Keep this with your registration paperwork; you may need it at the DMV.

How long will the dealer need my truck?The actual programming time is around 45 minutes, but scheduling, check-in, and programming queues mean you should expect to leave the truck for longer. Ask your service advisor for their best estimate based on current workload.

What I would do as an ownerCheck my VIN for open recalls, schedule N242438500 as soon as possible, keep the repair order and (if in California) the Proof of Correction Certificate, and file everything with my maintenance records in case questions come up later.