2021 Nissan Sentra Alternator Fault and Engine Noise TSB

Nissan has released Technical Service Bulletin (TSB) NTB22-096 to address specific issues affecting the 2021 Nissan Sentra. This bulletin details a condition where owners may experience a loss of power, unusual engine noise, and an illuminated battery warning light. The root cause has been identified as potential failures within the charging system, specifically involving the alternator and its associated components.

This TSB provides a clear repair path for technicians to resolve the underlying problem, ensuring the vehicle's charging system operates correctly. Addressing this issue promptly is crucial for maintaining vehicle performance and preventing further damage.

Symptoms of a Nissan Sentra Alternator Fault

Owners of affected 2021 Nissan Sentra vehicles may observe one or more of the following symptoms:

• Loss of power: The vehicle may feel sluggish or exhibit reduced acceleration capabilities.
• Loud noise from the front of vehicle/engine area while running: This noise is often described as abnormal or excessive.
• The battery light is ON: The battery warning indicator on the dashboard will illuminate, signaling a problem with the charging system.

These symptoms collectively point to a potential issue with the vehicle's electrical generation and power delivery, often indicating a Nissan Sentra alternator fault.

Diagnosis and Trigger Conditions

To confirm the issue, technicians will typically verify the presence of the symptoms described by the customer. A key diagnostic step involves confirming that the loud noise originating from the engine area is specifically coming from the generator, also known as the alternator. This confirmation helps to narrow down the problem to the charging system components.

Repair Procedure Summary

The repair outlined in TSB NTB22-096 involves replacing three key components within the charging and accessory drive system. Technicians are instructed to replace the Drive Belt Auto Tensioner, the Alternator, and the associated Drive Belt.

This comprehensive replacement ensures that all related parts that could contribute to the Nissan Sentra alternator fault are addressed. The procedure requires referring to the Electronic Service Manual (ESM) for detailed instructions on the removal and installation of the generator (alternator) and the drive belt auto tensioner, specifically for the MR20DD engine.

Required Parts

To perform this repair, specific genuine Nissan parts are required. These parts are essential for ensuring the longevity and proper function of the vehicle's charging system. The following components are to be replaced:

Description	Part Number	Quantity
TEN-PULLEY (Drive Belt Auto Tensioner)	11955-5TA0B	1
Alternator	23100-6LB0A	1
Drive Belt	11720-5TA0B	1

For warranty claims, the Alternator (part number 23100-*****) should be designated as the Primary Failed Part (PFP) under OP CODE GX34AA, SYM ZL, and DIA 32, with a flat rate time (FRT) of 2.6 hours.

What Owners Should Do

If your 2021 Nissan Sentra exhibits any of the described symptoms—loss of power, loud engine noise, or an illuminated battery light—it is recommended to contact your authorized Nissan dealer. The dealer will be able to diagnose the issue accurately and perform the necessary repairs as outlined in TSB NTB22-096. This repair ensures the proper functioning of your vehicle's charging system and prevents potential breakdowns.

---

Source: NHTSA ID: 10226131