2021 Nissan Sentra High Frequency Audio Noise TSB

Owners of certain 2021 Nissan Sentra SR and SV models may notice a high frequency noise emanating from the audio system. This issue, specifically a "HIGH FREQUENCY NOISE WITH AUDIO SYSTEM DISPLAY ON," is detailed in Nissan Technical Service Bulletin (TSB) NTB21-067A. This bulletin, an amendment to the original NTB21-067 published on July 29, 2021, provides guidance for technicians to diagnose and resolve the noise by updating the infotainment software.

Symptoms of High Frequency Audio Noise

The primary symptom is a high frequency (17 kHz) noise that occurs when the audio system display screen is turned ON. This noise can be present whether the audio system itself is playing or turned OFF. It's important to note that the 17 kHz range may not be audible to all individuals.

Crucially, the high frequency noise is not heard when the audio system display screen is turned OFF. This specific condition helps technicians isolate the source of the problem.

Diagnosis and Confirmation

Before proceeding with a repair, a technician will confirm the presence of the "Nissan Sentra high frequency noise" under the specified conditions. They will also check the current software version of the Audio Control Unit, looking for versions 321 or 420. These specific software versions are indicators that the vehicle may be affected by this particular issue.

Another critical diagnostic step involves checking Nissan's Service Comm system. If Service Comm indicates that campaign PM991 applies to your vehicle, technicians are instructed to perform the PM991 procedure instead of applying the steps outlined in this bulletin. This ensures the correct resolution is applied based on the vehicle's specific service history and applicable campaigns.

Important Warnings for Owners

Nissan emphasizes that this bulletin is intended for use by qualified technicians. Owners should be aware of the following:

• Do NOT assume that it applies: If you believe your vehicle has this condition, do not assume this bulletin applies. Your Nissan dealer will determine if the bulletin is relevant to your specific vehicle.
• Follow the repair procedure precisely: The repair process requires technicians to "MUST closely follow the entire SERVICE PROCEDURE located in NTB23-018 as it contains information that is essential to successfully completing this repair." This means the actual detailed steps for the software update are found in a separate, referenced bulletin, NTB23-018.
• PM991 takes precedence: If your vehicle is subject to campaign PM991, that procedure must be performed instead of this bulletin's recommendations.

Repair Procedure Summary

The resolution for the "Nissan Sentra high frequency noise" involves updating the infotainment software. After confirming the symptoms and the Audio Control Unit software version (321 or 420), the technician will proceed with the software update.

The detailed steps for performing the infotainment software update, including information on the latest software, specific procedures, and claims information, are provided in a separate document: Technical Service Bulletin NTB23-018. Technicians are required to refer to NTB23-018 to ensure the repair is completed correctly.

Owner Action

If you own a 2021 Nissan Sentra SR or SV and experience a high frequency (17 kHz) noise when your audio system display is on, especially if the noise disappears when the display is off, you should contact your authorized Nissan dealer. Explain the symptoms you are experiencing. The dealer will be able to diagnose the issue, confirm if your vehicle is affected by TSB NTB21-067A, and perform the necessary infotainment software update. This repair is typically covered under warranty if your vehicle meets the specified conditions.

Source: NHTSA ID: 10234061