Honda bulletin A18-090
What it saysThere is a software problem in the PCM, which may cause the MIL to come on with DTC P26A3 (electric water valve malfunction), DTC P100C (electric VTC motor speed signal circuit malfunction) and/or P0010 (variable valve… NHTSA’s full summary ↓
Honda filed this with NHTSA as a service bulletin dated Nov 14, 2023, received Oct 15, 2018, about the electrical system — 3 documents under this number. It names 1 model year (2018). 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 communicationService Bulletin - There is a software problem in the PCM, which may cause the MIL to come on with DTC P26A3 (electric water valve malfunction), DTC P100C (electric VTC motor speed signal circuit malfunction) and/or P0010 (variable valve timing control [VTC] malfunction). There are up to three updates that must be performed on applicable vehicles.
Trouble codes it names: P0010 P100C P26A3 U2600 1 of 4 read from the document itself
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| A18-090 | Service bulletin | Nov 14, 2023 | 10245549 | PDF, 260 KB |
| A18-090 | Service bulletin | Oct 17, 2019 | 10166784 | PDF, 209 KB |
| A18-090 | Service bulletin | Oct 6, 2018 | 10145430 | not found |
What the document itself lists
The manufacturer titles it “Product Update: 2018 Clarity Plug-In Hybrid E-VTC & 3-Way Valve”.
Part the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| 37805-5WJ-A61 | — | — |
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 1225A1 | Update the PCM software | 0.2 hrs |
Read by machine from the document NHTSA serves (2 pages), read Oct 4, 2026. A part number is shown only where it matches Honda’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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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 163 complaints with NHTSA since 2015. 73 of them name Engine, Electrical System, Power Train — 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.
On the 2018 Honda Clarity, the 20 owners who gave an odometer reading for Engine reported it at a median of 4,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
I bought this car used with a governmental help from replace my ride program, since I bough the car form a dealer ) within few days, I took it to the dealer twice for thermostat replacement and spark plugs. and recently, There was an extended warranty from Honda for the ac condenser as this car has a major problem with ac.
2018 Honda Clarity · Visibility/Wiper · filed with NHTSA Jul 13, 2024 · ODI 11601789
The vehicle exhibits a dangerous electrical defect involving uncontrolled power-cycling. After shutting down the car, it automatically restarts itself in a continuous loop. During these episodes, the dashboard flickers, the drivetrain shudders, and the vehicle becomes unresponsive to manual 'Stop' button or brake inputs.
2018 Honda Clarity · Electrical System · filed with NHTSA Jan 3, 2026 · ODI 11708588
The engine revs very high and the car dramatically slows down. This has happened three times (including today) in the two years I have owned the car. Once was extremely dangerous as it happened on an Interstate highway when traffic was at highway speeds. We were able to avoid getting in an accident though.
2018 Honda Clarity · Engine · filed with NHTSA Mar 25, 2023 · ODI 11513787
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 group4 other manufacturer communications filed against the Honda Clarity under the same component group (electrical system), newest first.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| ONL6CK09212022 | Service bulletin | Sep 21, 2022 | Owner's Notification Letter - Product Update - Our records indicate that a Product Update has not been completed on this vehicle… |
| A22090A | Service bulletin | Sep 16, 2022 | Dealer Message - In the event you experience a sub tank wire harness rodent damage on the 2017â2020 Clarity FCV, after repairing / replaci… |
| ONL6PH09152022 | Service bulletin | Sep 15, 2022 | Owner's Notification Letter - Our records indicate that a PRODUCT UPDATE has not been completed on this vehicle… |
| AJA11262 | Service bulletin | Oct 5, 2019 | Job Aid - American Honda has created an instructional video on how to replace the fuel cell stack. When working on or around the fuel cell s… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Honda, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Honda A18-090 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 A18-090 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 Honda warranty extension on file lists the ones Honda has filed.
Which vehicles does A18-090 cover?
The manufacturer filed it against 1 model year: 2018 Honda Clarity. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.