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Service bulletin M1391A

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 id10189980
Published by NHTSA2021-04-06
Manufacturer's numberM1391A
Manufacturer's date2021-03-18
NHTSA componentELECTRICAL SYSTEM; EQUIPMENT

NHTSA's summary

SERVICE BULLETIN M1391A: MIDTRONICS GRX-3110 SOFTWARE UPDATE. PURPOSE: REVISION. This bulletin is to inform the dealer network that a software update to the GRX-3110 is now available. HD BATTERY DIAGNOSTIC STATION (PART NUMBER: GRX-3110HD). Update 192-210335J addresses new battery part numbers for 2021 models and revised menu selections.

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

Electrical system, Equipment and accessories

Vehicles listed
HARLEY-DAVIDSON HARLEY-DAVIDSON

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