Toyota bulletin 23TC05
What it saysDP: A software update has been developed for certain 2023 model year bZ4X vehicles. NHTSA’s full summary ↓
Toyota filed this with NHTSA as a service bulletin dated Oct 4, 2023, received Aug 28, 2023, about the electrical system — 3 documents under this number: 23TC05_FAQ_10.04, 23TC05_Dealer Pa and 1 more. 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 communicationDP: A software update has been developed for certain 2023 model year bZ4X vehicles. It is designed to improve DC-charging performance, and enhance visualization of the remaining range, current state of charge (SOC), and real-life energy consumption.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 23TC05_FAQ_10.04 | Service bulletin | Oct 4, 2023 | 10245449 | not found |
| 23TC05_Dealer Pa | Service bulletin | Oct 4, 2023 | 10245448 | not found |
| 23TC05 | Service bulletin | Jul 27, 2023 | 10241408 | 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.
Doing the repair yourself, or pricing it before the shop does? Search the part by fitment on eBay Motors — the listing and the price are the seller’s.
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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 21 complaints with NHTSA since 2015. 3 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.
UNKNOWN , 11/26/2024 car in garage would not start, car was tow to Toyota and Toyota replaced the battery. then on 02/06/2025 vehicle was in garage and would not start and vehicle was tow again to Toyota dealer. Where dealer replaced 12 volt battery at 5,283 miles. And told us to put a battery charger on the battery
2023 Toyota bZ4X · Electrical System · filed with NHTSA Jun 10, 2025 · ODI 11666165
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 group25 other manufacturer communications filed against the Toyota bZ4X 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 |
|---|---|---|---|
| 26TC01 | Service campaign | Sep 8, 2026 | An electrical connection for the rear window defogger may not have been installed correctly during vehicle assembly. Overtime, this can caus… |
| 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… |
| T-TT-0779-25 | 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… |
| T-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… |
| T-SB-0120-20 REV2 | Service bulletin | Jan 30, 2025 | OBSOLETE NOTICE January 30, 2025: This bulletin is now obsolete. Please see T-SB-0015-25. |
| T-SB-0015-25 | Service bulletin | Jan 29, 2025 | Some 2021 – 2025 model year Toyota vehicles may require the download and installation of vehicle specific software or configuration software… |
| T-SB-0111-20 REV2 | Service bulletin | Jan 23, 2025 | OBSOLETE NOTICE January 23, 2025: This bulletin is now obsolete. Please see T-SB-0011-25. |
| T-SB-0011-25 | 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 Toyota, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Toyota 23TC05 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 23TC05 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 23TC05 cover?
The manufacturer filed it against 1 model year: 2023 Toyota bZ4X. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.