# Service bulletin T\-TT\-0571\-19

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.

- Type: Service bulletin
- NHTSA id: 10165994
- Published by NHTSA: 2019\-10\-15
- Manufacturer's number: T\-TT\-0571\-19
- Manufacturer's date: 2019\-09\-05
- NHTSA component: ELECTRICAL SYSTEM

## NHTSA's summary

TT: Some 2020 model year Tundra and Sequoia vehicles may experience a B15DB or intermittent Wi\-Fi inoperative \(Wi\-Fi icon greyed out\). To simplify the diagnosis of the inoperative Wi\-Fi, refer to the procedure below to prevent unnecessary parts replacement.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2019/MC-10165994-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2019/MC-10165994-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system

## Vehicles listed

- 2020 TOYOTA SEQUOIA
- 2020 TOYOTA TUNDRA

## Recalls for the same vehicles and component

- [2021723](/recalls/tc/2021723.md), 2021-11-24: Electrical
- [21V688000](/recalls/nhtsa/21V688000.md), 2021-09-02: EXTERIOR LIGHTING:HEADLIGHTS; ELECTRICAL SYSTEM:WIRING
- [20V410000](/recalls/nhtsa/20V410000.md), 2020-07-15: EXTERIOR LIGHTING:TURN SIGNAL; ELECTRICAL SYSTEM:WIRING

## Other bulletins for the same vehicles and component

- [T\-SB\-0106\-22 Rev2](/bulletins/11028726.md), 2026-02-11, Service bulletin: ELECTRICAL SYSTEM. OBSOLETE NOTICE January 30, 2026: This bulletin is now obsolete. Please see T\-SB\-0001\-26.
- [T\-SB\-0001\-26](/bulletins/11028722.md), 2026-02-11, Service bulletin: ELECTRICAL SYSTEM. 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\-SB\-0058\-23 Rev1](/bulletins/11020657.md), 2025-07-10, Service campaign: ELECTRICAL SYSTEM. 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\-25](/bulletins/11019332.md), 2025-06-06, Service bulletin: ELECTRICAL SYSTEM. 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\-25](/bulletins/11018329.md), 2025-05-15, Service bulletin: ELECTRICAL SYSTEM. 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 Rev2](/bulletins/11016786.md), 2025-04-08, Service bulletin: ELECTRICAL SYSTEM. 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 Rev2](/bulletins/11015500.md), 2025-03-11, Service bulletin: ELECTRICAL SYSTEM. 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.
- [TSB002620](/bulletins/10247828.md), 2023-12-26, Service bulletin: UNKNOWN OR OTHER; EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; ELECTRICAL SYSTEM:SOFTWARE; FORWARD COLLISION AVOIDANCE; AIR BAGS. TSB: All 2020 ? 2023 model year 4Runner, 2018 ? 2022 model year Sequoia, 2018 ? 2023 model year Tacoma, and 2018 ? 2021 model year Tundra vehicles are equipped with Pre\-collision System \(PCS\) and Dynamic Radar Cruise Control \(DRCC\) as part of the Toyota Safety Sense \(TSS\) package. The PCS and DRCC systems are designed to help mitigate a potential collision and maintain a pre\-determined traveling distance. It is recommended to disable the PCS and DRCC systems on vehicles that have been modified \(ride height, oversized wheels/tires, brush bars, etc.\) in a way that potentially disrupts the functionality of these systems. Vehicle owner?s written consent is required before performing the calibration to permanently disable the PCS and DRCC systems. Follow the Repair Procedure in this bulletin to disable the PCS and DRCC systems.
- [T\-SB\-0057\-18](/bulletins/10238157.md), 2023-06-26, Service bulletin: EQUIPMENT; ELECTRICAL SYSTEM. TSB: The Immobilizer and Smart Key Reset is a feature that allows the registration of new keys when all master keys are lost. Once the system is reset, all previously registered keys will be erased. Follow the procedures in this bulletin to reset a vehicle Immobilizer or Smart Key system.
- [T\-TT\-0687\-22](/bulletins/10210373.md), 2022-04-18, Service bulletin: ELECTRICAL SYSTEM:12V/24V/48V BATTERY. TT: When customers have a concern about a discharged battery, no start, or general battery concern, the DCA\-8000 is the only appropriate tool to use for diagnosis

JSON: [/v1/bulletins/10165994](/v1/bulletins/10165994)

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