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Service bulletin 20NA165

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10214202
Published by NHTSA2022-06-21
Manufacturer's number20NA165
Manufacturer's date2022-01-31
NHTSA componentENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM):SOFTWARE; EQUIPMENT ADAPTIVE/MOBILITY

NHTSA's summary

This technical bulletin provides repair information to correct a customer concern of Flutter or Boom Noise at 1200 RPM- Service Calibration.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine, Equipment and accessories, Engine control module

Vehicles listed
BUICK ENCORE GX2021
CHEVROLET TRAILBLAZER2021

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Other bulletins for the same vehicles and component
PIP5628F2023-05-15. Service bulletin. This Preliminary information communicates information that will need to be provided to TAC to aid in diagnosing if a vehicle comes in with misfire and DTC Codes P0300 - P0308 and/or P050D
21NA2572022-02-14. Service bulletin. This service bulletin provides a service procedure to correct a customer concern of a Malfunction Indicator Lamp (MIL) Illuminated - DTC P3075 Set.
21NA2562022-02-14. Service bulletin. This service bulletin provides repair information for dealers/technicians to correct a customer concern of a Malfunction Indicator Lamp Illuminated with DTC P26BB Set.
21NA2152021-12-27. Service bulletin. This technical bulletin provides a procedure to correct a customer concern of a Pop Noise Heard on Heavy Acceleration Only.
A2023219902021-08-09. Service bulletin. Service Update. Certain vehicles may have engine control module software that leads to erroneous additional fuel enrichment under rare driving conditions. Dealers are to reprogram the engine control module.