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Service bulletin T-TT-0484-18-Rev

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 id10155248
Published by NHTSA2019-03-25
Manufacturer's numberT-TT-0484-18-Rev
Manufacturer's date2019-02-28
NHTSA componentELECTRICAL SYSTEM

NHTSA's summary

TT: Some customers may experience echoing on the line calling the vehicle when using Bluetooth Hands Free. This is caused by the phone Hands Free volume being too low. These settings may need to be reapplied any time the phone is paired to a new head unit, a phone update is applied, or the phone is un-paired and re-paired.

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

Vehicles listed
TOYOTA 4RUNNER2017, 2018, 2019
TOYOTA AVALON2017, 2018
TOYOTA HIGHLANDER2016, 2017, 2018, 2019
TOYOTA PRIUS2016, 2017, 2018, 2019
TOYOTA PRIUS V2016, 2017
TOYOTA PRIUS V2018 (the catalog's model; the bulletin names a series or trim of it)
TOYOTA SEQUOIA2016, 2017, 2018, 2019
TOYOTA SIENNA2016, 2017, 2018, 2019
TOYOTA TACOMA2016, 2017, 2018, 2019
TOYOTA TUNDRA2016, 2017, 2018, 2019
TOYOTA YARIS2018

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

Recalls for the same vehicles and component
20217232021-11-24. Electrical
21V6880002021-09-02. EXTERIOR LIGHTING:HEADLIGHTS; ELECTRICAL SYSTEM:WIRING
20V4100002020-07-15. EXTERIOR LIGHTING:TURN SIGNAL; ELECTRICAL SYSTEM:WIRING
20202842020-06-25. Electrical
19V8760002019-12-11. ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL
20194342019-08-28. Electrical
18V6850002018-10-04. ELECTRICAL SYSTEM:SOFTWARE; AIR BAGS
20184772018-09-05. Electrical
18V5790002018-09-05. ELECTRICAL SYSTEM:WIRING
20181002018-02-21. Electrical

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
T-SB-0106-22 Rev22026-02-11. Service bulletin. OBSOLETE NOTICE January 30, 2026: This bulletin is now obsolete. Please see T-SB-0001-26.
T-SB-0001-262026-02-11. Service bulletin. Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software.
T-TT-0790-252025-09-09. Service bulletin. Some customers may experience echoing on the line calling the vehicle when using Bluetooth Hands Free. This is caused by the phone Hands Free volume being too low.
T-SB-0058-23 Rev12025-07-10. Service campaign. The air conditioning dye injection tool kit has been developed to aid in identifying the location of air conditioning refrigerant leaks. The procedures outlined in this Service Bulletin aid in locating, inspecting, and repairing refrigerant leaks.
T-TT-0780-252025-06-06. Service bulletin. To assist with the early detection and early resolution of audio related concerns you may be asked to recover MMR data from the head unit. The following steps are instructions on how to retrieve the data from the system and are only to be used when requested by FTS and/or FPE.
T-TT-0780-252025-05-15. Service bulletin. To assist with the early detection and early resolution of audio related concerns you may be asked to recover MMR data from the head unit. The following steps are instructions on how to retrieve the data from the system and are only to be used when requested by FTS and/or FPE.
T-SB-0106-22 Rev22025-04-08. Service bulletin. Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software. The SST is used with applicable vehicles to deliver the update, however, the process for generating license keys differs from previous generations.
T-SB-0106-22 Rev22025-03-11. Service bulletin. Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool (SST) USB flash drive to update the map, points of interest, and system software. The SST is used with applicable vehicles to deliver the update, however, the process for generating license keys differs from previous generations.
T-TT-0754-242024-07-06. Service bulletin. Customers have expressed concerns about the performance of Qi Wireless Chargers. Wireless chargers on applicable vehicles are designed to work with Qi Certified devices only. MagSafe devices, that are not Qi Certified, may not charge as expected with Qi Wireless Chargers.
T-TT-0754-242024-07-06. Service bulletin. Customers have expressed concerns about the performance of Qi Wireless Chargers. Wireless chargers on applicable vehicles are designed to work with Qi Certified devices only. MagSafe devices, that are not Qi Certified, may not charge as expected with Qi Wireless Chargers.