Lexus bulletin L-TT-0327-23
What it saysEV Battery ECU Shows Software Update Available "YES", After Health Check NHTSA’s full summary ↓
Lexus filed this with NHTSA as a service bulletin dated Apr 12, 2024, received Jul 6, 2024, about the electrical system — 2 documents under this number: L-TT-0327-23 Rev2 (2 filings). It names 1 model year (2023). 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.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationEV Battery ECU Shows Software Update Available "YES", After Health Check
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| L-TT-0327-23 Rev2 | Service bulletin | Apr 12, 2024 | 11003626 | |
| L-TT-0327-23 Rev2 | Service bulletin | Apr 12, 2024 | 11003571 |
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.
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What owners reported
Source: NHTSA complaint databaseOwners of the 1 model year this bulletin names have filed 11 complaints with NHTSA since 2015. 4 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.
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 group26 other manufacturer communications filed against the Lexus RZ under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Lexus list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| L-TT-0326-23 REV2 | Service bulletin | Aug 19, 2025 | Some customers may experience operational difficulties with some telematics features which they cannot resolve on their own. These resources… |
| 25LC03 | Service campaign | Aug 5, 2025 | A software update has been developed for certain 2023 model year RZ450e vehicles. It is designed to improve DC-charging performance, and enh… |
| L-SB-0043-23 REV1 | Service bulletin | 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… |
| L-TT-0340-25 | Service bulletin | Apr 2, 2025 | 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. T… |
| L-SB-0036-22 REV2 | Service bulletin | Feb 10, 2025 | Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated without replacing the ECU. Flash calibration updates for… |
| L-SB-0013-24 REV1 | Service bulletin | Feb 10, 2025 | 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… |
| L-SB-0021-23 REV2 | Service bulletin | Jan 30, 2025 | Some 2022 – 2025 model year Lexus vehicles may require the download and installation of vehicle specific software or configuration software… |
| L-SB-0035-22 REV2 | Service bulletin | Jan 23, 2025 | When certain vehicle ECUs are replaced, the ECU Security Key must be written in order for that ECU to communicate on the vehicle network. Th… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Lexus, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Lexus L-TT-0327-23 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 L-TT-0327-23 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 L-TT-0327-23 cover?
The manufacturer filed it against 1 model year: 2023 Lexus RZ. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.