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Service bulletins for the 2018 Honda Clarity

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.

46 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

Bulletins, newest first
A19-0062019-02-21. Service bulletin. FUEL SYSTEM, OTHER:STORAGE:TANK ASSEMBLY. Service Bulletin - The telematics system is reporting deterioration of the fuel cell stack. This deterioration can reduce fuel cell output. Water improperly discharged inside the fuel cell stack mixes with hydrogen and oxygen, generating hydrogen peroxide. The hydrogen peroxide/water combination concentrates in one area, accelerating the deterioration of the electrolyte membrane in the fuel cell.
ABOM011420199012019-02-10. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT:ELECTRICAL. "Dealer message - Today American Honda is notifying dealers of two product updates affecting certain 2017-18 Clarity Fuel Cell vehicles. The first is a software update to the hydrogen tank temperature sensors. The second is a product update to replace the fuel cell stack on a limited number of vehicles due to premature deterioration."
A19-0062019-02-10. Service bulletin. FUEL SYSTEM, DIESEL:STORAGE:TANK ASSEMBLY; ELECTRICAL SYSTEM. "Service bulletin - The telematics system is reporting deterioration of the fuel cell stack. This deterioration can reduce fuel cell output. Water improperly discharged inside the fuel cell stack mixes with hydrogen and oxygen, generating hydrogen peroxide. The hydrogen peroxide/water combination concentrates in one area, accelerating the deterioration of the electrolyte membrane in the fuel cell."
A19-0012019-02-10. Service bulletin. ELECTRICAL SYSTEM. "Service bulletin - The vehicle may incorrectly set DTC P1F76 (main hydrogen tank temperature sensor malfunction) or P1F77 (sub hydrogen tank temperature sensor malfunction). The fuel cell communication control (IR) software is not current."
APaS120520189012018-12-14. Service bulletin. ENGINE AND ENGINE COOLING. "Dealer message - AHM is studying the current replacement need for the ION filter (PN 3H450-5WM-A01). We would like to collect several samples in the field for this study. A supply of bags and identifying labels will be sent to your dealership for this project."
A18110B2018-11-30. Service bulletin. ENGINE AND ENGINE COOLING. "ServiceNews Article - When replacing the fuel cell stack, make sure you bleed the air from the fuel cell insulating system exactly as called out in the fuel cell insulating fluid replacement procedure in the service information. If you don't, you'll get an FC Coolant Low. See Your Dealer message in the driver information interface shortly after your repair and/or will damage the new fuel cell stack."
A18-0972018-11-13. Service bulletin. ELECTRICAL SYSTEM. Service bulletin - The Clarity Plug-In Hybrid and Clarity Electric may not start charging when plugged in or may stop charging before the high-voltage lithium-ion battery is full.
ABOM100420189012018-10-15. Service bulletin. ELECTRICAL SYSTEM. Dealer message - Today, American Honda is announcing several product updates a?ecting certain 2018 Honda Clarity Plug-In Hybrid (PHEV) models. There may be multiple combinations of these campaigns per VIN. To clearly identify each vehicle's needs, be sure to do an iN VIN status inquiry for units in dealer inventory and during customer visits. Also, to help ensure customer satisfaction and reduce inconvenience, make sure all parts and software are available when customers arrive. PROBLEM Climate Control: In certain operating conditions, a software issue with the climate control unit and PCM software may lead to incorrect operation of the coolant 3-way valve, causing DTC P26A3 (electric water valve malfunction) to set. Electric Valve Timing Control (EVTC): In certain operating conditions, an issue with the PCM software may lead to incorrect operation of the EVTC, causing DTC P100C (electric VTC motor signal circuit malfunction) and/or P0010 (variable valve timing control [VTC] malfunction) to set. Driver Information Interface: In certain EV mode driving conditions, a software issue with the driver information interface may lead to the HV range reading unusually high (more than 1,000 miles remaining). Warranty information CD placed in the vehicle did not list the correct warranty coverage for the state of Oregon. This may cause customer confusion regarding coverage.
A18-0962018-10-15. Service bulletin. EQUIPMENT. Service bulletin - During vehicle assembly, the warranty information CD that was placed in the vehicle did not list the correct warranty coverage for the state of Oregon. The failure to include the proper warranty coverage may cause confusion and potential customer dissatisfaction.
A18-0912018-10-15. Service bulletin. ELECTRICAL SYSTEM. Service bulletin - There is a software error in the miles per gallon calculation, which affects the HV range display by reading unusually high.
A18-0902018-10-15. Service bulletin. ELECTRICAL SYSTEM. Service 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).
A18-0892018-10-15. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. Service bulletin - There is a software problem in the climate control unit when running the heater, which may turn the MIL on. There are up to three updates that must be performed on applicable vehicles. Check the iN VIN status inquiry for applicability.
A18-0792018-10-15. Service bulletin. ELECTRICAL SYSTEM. Service bulletin - This bulletin is replaced by S/B 18-089, Product Update: 2018 Clarity Plug-In Hybrid EVTC & 3-Way Valve Software Update (P100C/P0010/P26A3)
A18-0692018-10-15. Service bulletin. ELECTRICAL SYSTEM. Service bulletin - This bulletin is replaced by S/B 18-091, Product Update: 2018 Clarity PHEV Driver Display Software Update (Mileage)
A18-0972018-10-15. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY. Service bulletin - The Clarity Plug-In Hybrid and Clarity Electric may not start charging when plugged in or may stop charging before the high-voltage lithium-ion battery is full. The battery charger software does not start charging or may stop before charging is complete in areas with poor or fluctuating power quality.
A18-0792018-08-06. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. Service bulletin - The MIL comes on with DTC P100C (electric VTC motor speed signal circuit malfunction) and/or P0010 (variable valve timing control [VTC] malfunction).
A18-0792018-07-30. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM). Service bulletin - The MIL comes on with DTC P100C (electric VTC motor speed signal circuit malfunction) and/or P0010 (variable valve timing control [VTC] malfunction).
A17070B2018-07-16. Service bulletin. ENGINE AND ENGINE COOLING. Servicenews article - The Clarity Fuel Cell vehicle has two very different cooling systems. One system cools the fuel cell system; the other one cools the inverter system. The fuel cell system uses a 50% coolant mixture called fuel cell insulating fluid, This fluid can't be mixed with any other fluid. Doing so cuts its insulating properties and will damage the fuel cell system.
ATS 1805032018-07-16. Service bulletin. ELECTRICAL SYSTEM. Tech line summary article - We're getting reports of the HV range shown in the driver information interface reading unusually high (more than 1,000 miles remaining). How high it gets depends on driving style, and it typically happens after many EV trips not using the engine.
A18-0692018-07-02. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. Service bulletin - The HV range display reading is unusually high. There is a software error in the miles per gallon calculation, which affects the remaining HV range display.
A15060D2017-08-25. Service bulletin. STEERING: STEERING WHEEL/HANDLE BAR; STEERING. Service news article - To prevent damage during shipping, leather-wrapped steering wheels come with a protective plastic covering. The easiest way to remove it during PDI is to grab the covering with both hands near the top of the steering wheel and pull it toward you, like you see here. The covering comes right off.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.