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Service bulletin TSB004622

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 id10220144
Published by NHTSA2022-09-15
Manufacturer's numberTSB004622
Manufacturer's date2022-05-05
NHTSA componentFUEL SYSTEM, GASOLINE; ELECTRICAL SYSTEM

NHTSA's summary

TSB: Some 2016 ? 2019 model year Mirai vehicles may exhibit a warning message, ?FC malfunction, return vehicle to dealer for service.? This message is accompanied by Diagnostic Trouble Code (DTC) P1DEF (450 FC Stack Performance). The Fuel Control Module (FCM) calibration has been revised to address this condition

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, Fuel system

Trouble codes named

P1DEF

Vehicles listed
TOYOTA MIRAI2016, 2017, 2018, 2019

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
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T-SB-0003-222022-02-14. Service bulletin. TSB This Service Bulletin includes guidelines meant to help determine whether to repair or replace a wire harness assembly based on damage type. This Service Bulletin should be used in conjunction with the applicable model and model year Electronic Wiring Diagram (EWD) and/or Repair Manual.
T-TT-0660-212021-09-13. Service bulletin. TT: During vehicle inspections, when the vehicle under covers are removed, debris is found on the undercover near the end of the hydrogen tank. Upon closer inspection the debris is found to be coming from the end protector of the tank.