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ECM Service Update N252510321: What Owners Need to Know (Aug 14, 2025)

GM has released Service Update #N252510321 for select Cadillac, Chevrolet, and GMC vehicles. This is a phased launch rolling out August 2025 and may arrive as an over-the-air (OTA) update or be performed at a dealer. The update adds a Driver Information Center (DIC) warning message when DTC P0016 sets, alongside the existing Check Engine Light.

  • Bulletin ID: N252510321

  • Title: ECM Software Update

  • Release: August 2025 (Revision 00)

  • Scope: Dealer inventory and customer vehicles (phased)

  • Key change: Adds a DIC message when P0016 sets

  • Parts required: None (software only)

Source attribution for publishing: General Motors Service Update N252510321, released August 2025. Referenced language and details used with acknowledgment to GM Field Action documentation.

Quick Takeaways

  • If your vehicle is covered, you may see an on-screen OTA prompt or be able to have the dealer update it.

  • The update does not change drivability by itself; it enhances the warning behavior for P0016 so the driver gets a clearer message in addition to the MIL.

  • P0016 is a cam/crank correlation diagnostic trouble code. If it sets, do not ignore it—schedule diagnosis.

Why this matters: What is P0016?

P0016 indicates a misalignment between the crankshaft and camshaft signals (Bank 1, Sensor A). That can be caused by several conditions (e.g., sensor issues, wiring faults, timing correlation concerns). The new DIC message makes it obvious to the driver that a correlation fault occurred so action isn’t delayed.

This software update does not diagnose or repair the root cause of P0016; it improves visibility so owners seek service promptly.

Who is affected?

Model years covered in this field action (per GM bulletin):

  • Cadillac:

    • Escalade (2022–2023)

    • Escalade ESV (2022–2023)

  • Chevrolet:

    • Silverado 1500 (2021–2024)

    • Suburban (2022–2023)

    • Tahoe (2022–2023)

  • GMC:

    • Sierra 1500 (2021–2024)

    • Yukon (2022–2023)

    • Yukon XL (2022–2023)

Note: For 2023 and 2024 model-year vehicles, GM indicates eligible units may be updated via OTA or at the dealer, depending on status.

How the rollout works (Owner’s view)

This is a phased release. You may experience one of the following:

  1. OTA Update Prompt

    • A notification appears on your infotainment/DIC indicating an update is available.

    • Accept the update when parked with reliable connectivity and adequate vehicle battery state.

    • Follow on-screen instructions until completion.

  2. Dealer Update

    • If you don’t receive an OTA prompt or prefer in-person service, the dealer can reprogram the ECM using the bulletin procedure.

    • No parts are required—it’s a calibration/software reflash.

How to check if you’re included

  • Owners: Contact your Chevrolet/GMC/Cadillac dealer with your VIN and ask if Service Update N252510321 is open on your vehicle. (Dealers verify through GM Global Warranty Management – Investigate Vehicle History (IVH).)

  • Important: GM instructs dealers to always check IVH and not to rely on Service Information VIN search for field action eligibility.

What dealers were told (summary)

  • This service update applies to dealer inventory and customer vehicles returning for any reason.

  • Always verify in IVH that the field action is open before performing any repair.

  • Vehicles may auto-close in IVH after successful OTA. Check current status before proceeding.

  • Refer to TSB 21-NA-043 for maintaining vehicles in inventory.

  • Correction: Reprogram the ECM to enable the DIC message when P0016 sets.

  • Parts: Not applicable.

Frequently Asked Questions

Will this update fix P0016?No. It adds a DIC message when P0016 sets. If the code is present, a diagnostic workup is still required.

My truck runs fine—should I still do it?Yes. This is an official GM service update. It improves visibility if P0016 occurs later.

Is this mandatory?Field actions like this are strongly recommended. If OTA is offered for your vehicle, you can accept it at home. Otherwise, the dealer can perform it.

How long does the dealer update take?It’s a software reprogramming (no parts). Actual bay time varies by dealer throughput and process.

I have aftermarket accessories or a monitor plugged into OBD-II. Will that block OTA?Some accessories can interfere with certain communications. For best results during OTA, disconnect non-essential OBD-II devices, ensure good connectivity, and follow the on-screen instructions. If OTA fails or never prompts, ask your dealer to perform the update in-shop.

What to do next (owners)

  1. Watch for an OTA prompt on the dash/infotainment.

  2. If no prompt appears, call your dealer with your VIN and ask if N252510321 is open.

  3. If P0016 or a Check Engine Light appears, schedule service promptly—don’t rely on the DIC message alone.

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