Toyota bulletin T-SB-0021-26
What it saysSome 2020 – 2024 model year Highlander and Highlander Hybrid vehicles may exhibit a condition in which the air conditioner does not cool due to a leak and/or corrosion in the rear underbody air conditioner tube… NHTSA’s full summary ↓
Toyota filed this with NHTSA as a service bulletin dated Mar 18, 2026, received Apr 8, 2026, about the electrical system. It names 5 model years (2020–2024). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
Get the next Toyota Highlander bulletin by email Weekly, only when something new is filed. Nothing else; one-click unsubscribe.
What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationSome 2020 – 2024 model year Highlander and Highlander Hybrid vehicles may exhibit a condition in which the air conditioner does not cool due to a leak and/or corrosion in the rear underbody air conditioner tube and accessory assembly. The anti-corrosion material has been updated to reduce the possibility of this condition.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| T-SB-0021-26 | Service bulletin | Mar 18, 2026 | 11031158 | not found |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themA vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
Email me new Toyota bulletins for the Highlander
A weekly email, sent only in a week when Toyota files something new with NHTSA for the model you pick — service bulletins, campaigns, warranty extensions, over-the-air notices, every model year. Nothing else is sent; one-click unsubscribe in every message. Separate from recall alerts.
What owners reported
Source: NHTSA complaint databaseOwners of the 5 model years this bulletin names have filed 1,395 complaints with NHTSA since 2015. 6 of them name Electrical System — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
The contact owns a 2021 Toyota Highlander Hybrid. The contact stated that upon starting the vehicle, the instrument panel lights were flashing. The vehicle then independently turned off and restarted repeatedly. The vehicle was towed to the dealer, where it was determined that the battery level was low and needed to be replaced.
2021 Toyota Highlander · Electrical System · filed with NHTSA Feb 26, 2026 · ODI 11720641
The contact owns a 2022 Toyota Highlander Hybrid. The contact stated that the second-row seats had been making an abnormal rattling sound. Additionally, the contact stated that there was an abnormally strong foul odor inside the vehicle.
2022 Toyota Highlander · Electrical System · filed with NHTSA Mar 5, 2026 · ODI 11722206
The contact owns a 2023 Toyota Highlander Hybrid. The contact stated that while depressing the brake pedal, there was a hesitation, and the vehicle surged forward before coming to a stop. There were no warning lights illuminated.
2023 Toyota Highlander · Electrical System · filed with NHTSA Aug 28, 2024 · ODI 11611346
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the electrical system
Source: same model, same component group41 other manufacturer communications filed against the Toyota Highlander under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Toyota list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 22TE09 | Warranty extension | May 14, 2026 | Although the HV Floor Under Wire Harness and Rear Traction Motor Cable is covered by Toyota’s New Vehicle Limited Warranty for 3 years or 36… |
| T-SB-0106-22 OBSOLETE | Service bulletin | Jan 30, 2026 | OBSOLETE NOTICE January 30, 2026: This bulletin is now obsolete. Please see T-SB-0001-26. |
| T-SB-0001-26 | Service bulletin | Jan 28, 2026 | Some 2018 – 2024 model year Toyota vehicles equipped with a Premium Audio with Dynamic Navigation System require a Special Service Tool… |
| T-SB-0083-25 | Service bulletin | Nov 7, 2025 | A new head unit software update is available for 2022 – 2025 model year Tundra, and Tundra Hybrid; 2023 – 2025 model year Corolla Cross, Cor… |
| 25TD01 | Service campaign | Sep 25, 2025 | The subject vehicles are equipped with a rear motor unit and an HV Floor Under Wire that provide high voltage to operate the motor. Mud, wat… |
| T-SB-0015-24 REV2 | Service bulletin | Sep 9, 2025 | A new head unit software update is available for 2023 model year Corolla Cross, Corolla Cross Hybrid, Highlander, Highlander Hybrid, and Mir… |
| T-TT-0790-25 | Service bulletin | Aug 20, 2025 | Some customers may experience echoing on the line calling the vehicle when using Bluetooth Hands Free. This is caused by the phone Hands Fre… |
| T-SB-0058-23 REV1 | Service campaign | Jun 13, 2025 | The air conditioning dye injection tool kit has been developed to aid in identifying the location of air conditioning refrigerant leaks. The… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Toyota, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Toyota T-SB-0021-26 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the T-SB-0021-26 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every Toyota warranty extension on file lists the ones Toyota has filed.
Which vehicles does T-SB-0021-26 cover?
The manufacturer filed it against 5 model years: 2024 Toyota Highlander, 2023 Toyota Highlander, 2022 Toyota Highlander, 2021 Toyota Highlander, 2020 Toyota Highlander. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.