Service bulletin T-TT-0746-24

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)
Type	Service bulletin
NHTSA id	10251071
Published by NHTSA	2024-03-04
Manufacturer's number	T-TT-0746-24
Manufacturer's date	2024-01-23
NHTSA component	ENGINE AND ENGINE COOLING

NHTSA's summary

TT: Some 2017-2020MY and 2022-2024MY 86 vehicles may experience metallic knocking noise from the engine at all speeds. Should this condition occur, please contact TAS and your FTS to document repair information.

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

Vehicles listed
TOYOTA 86	2017, 2018, 2019, 2020
TOYOTA redundant 86	2022 to 2024

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
T-PANT-2024-004-	2024-04-15. Service bulletin. This is to advise of various price adjustments that will affect Toyota Genuine Motor Oil and Long Life Coolant, effective March 1, 2024. These products are ordered through the Toyota Complete Maintenance Care (TCMC) website.
T-TT-0628-20	2020-11-30. Service bulletin. TT: HVAC drain tube is found to be blocked/clogged.
T-SB-0156-19 Rev	2020-08-24. Service bulletin. TSB: Some 2017 - 2020 model year 86 vehicles with automatic transmissions may exhibit one or both of the following conditions: ?MIL ON condition with Diagnostic Trouble Code (DTC) P0300. ?Rough idle at cold start noticeable when engine coolant temperature is around 50°F (10°C). Follow the Repair Procedure in this bulletin to address this condition.
T-TT-0468-17 Rev	2020-08-17. Service bulletin. TT: HVAC drain tube is found to be blocked/clogged.
T-SB-0156-19	2019-12-16. Service bulletin. TSB: Some 2017 ? 2020 model year 86 vehicles with automatic transmissions may exhibit one or both of the following conditions: ? MIL ON condition with Diagnostic Trouble Code (DTC) P0300. ? rough idle at cold start noticeable when engine coolant temperature is around 50°F (10°C). Follow the Repair Procedure in this bulletin to address this condition.
T-SB-0134-16-Rev	2019-09-03. Service bulletin. TSB: REVISION NOTICE July 01, 2019 Rev2: ? Applicability has been updated to 2019 ? 2020 model year Toyota vehicles. ? The Techstream Preparation and Process Overview sections have been updated. October 30, 2017 Rev1: ? Applicability has been updated to include 2018 model year vehicles. Any previous printed versions of this bulletin should be discarded. SUPERSESSION NOTICE The information contained in this bulletin supersedes SB No. T-SB-0012-13. Service Bulletin No. T-SB-0012-13 is obsolete and any printed versions should be discarded. Be sure to review the entire content of this bulletin before proceeding. Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated without replacing the ECU. Flash calibration updates for specific vehicle models/ECUs are released as field-fix procedures described in individual Service Bulletins. This bulletin details the Techstream ECU flash reprogramming process and outlines use of the Technical Information System (TIS) and the Calibration Update Wizard (CUW). Flash calibration updates can only be applied to the vehicle/ECU combination for which they are intended. ECUs have internal security that will not allow them to be programmed with another ECU?s information. NOTE ECU is a Toyota term used to describe integrated computerized devices responsible for managing the operation of a system or subsystem. For the purposes of this bulletin, the term ?ECU? is used as a generic label for the following SAE J1930 standard references: ? Powertrain Control Module (PCM) ? Engine Control Module (ECM) ? Transmission Control Module (TCM) ? Any other Toyota specific control unit
T-SB-0154-18	2019-02-19. Service bulletin. TSB: Some 2017 ? 2019 model year 86 vehicles may exhibit a MIL ON condition with Diagnostic Trouble Codes (DTCs) P219A and P119F. The Engine Control Module/ECM (SAE Term: Powertrain Control Module/PCM) logic has been updated, in addition to valve adjustment to prevent this condition. Follow the Repair Procedure in this bulletin to address this condition.
T-SB-0134-16	2018-11-26. Service bulletin. TSB: Supersession Notice. Flash reprogramming allows the ECU software to be updated without replacing the ECU. Flash calibration updates for specific vehicle models/ECUs are released as field-fix procedures described in individual Service Bulletins. This bulletin details the Techstream ECU flash reprogramming process and outlines use of the Technical Information System (TIS) and the Calibration Update Wizard (CUW). Flash calibration updates can only be applied to the vehicle/ECU combination for which they are intended. ECUs have internal security that will not allow them to be programmed with another ECU?s information.