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Service bulletins for the 2021 Toyota Sienna

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.

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

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Only bulletins with component: Electrical system are shown. Show all

Bulletins, newest first
TSB0018232024-04-01. Service bulletin. ELECTRICAL SYSTEM:PROPULSION SYSTEM:HYBRID MANAGEMENT:POWER CONTROL UNIT/MODULE (HPCU); ELECTRICAL SYSTEM; ELECTRICAL SYSTEM:INSTRUMENT PANEL:FUEL GAUGE. TSB: Some 2021 ? 2023 model year Sienna Hybrid vehicles may exhibit a MIL ON condition with Diagnostic Trouble Code (DTC) P060694 (Hybrid/EV Powertrain Control Module Processor Unexpected Operation) present. The Hybrid Vehicle Control Computer logic has been modified to reduce the possibility of this DTC setting incorrectly. Follow the Repair Procedure in this bulletin to address this condition.
TSB0104212024-04-01. Service bulletin. SERVICE BRAKES, HYDRAULIC; ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING:COOLING SYSTEM; LANE DEPARTURE. TSB: Some 2018 ? 2024 model year Toyota vehicles equipped with an A25A-FKS, A25A-FXS, M20A-FKS, or M20A-FXS engine may exhibit one or more of the following conditions: ?Milky/discolored engine oil. ?An ?Oil Pressure Low? warning message on the Multi-information Display (MID). ?A MIL ON condition with Diagnostic Trouble Codes (DTCs) P05202A (Engine Oil Pressure Sensor/Switch ?A? Signal Stuck in Range) and/or P052477 (Engine Oil Pressure Too Low [Severe]) present. Moisture from blow-by gases condenses and accumulates in the engine oil during short trips in extreme cold weather. When the moisture in the oil freezes, the oil pressure may drop, and the aforementioned warning indicators may display. Follow the procedures in this bulletin to address these conditions.
TTT0716222023-12-26. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. TT: Vehicle option selection during identification process when connecting Techstream for diagnosis/repair.
TSB008523A2023-12-26. Service bulletin. ELECTRICAL SYSTEM:PROPULSION SYSTEM:HYBRID MANAGEMENT; ELECTRICAL SYSTEM. TSB: Some 2016 ? 2023 model year Toyota vehicles may exhibit a hybrid system warning lamp occurring in below-freezing temperatures (below 32°F or 0°C). After performing a Health Check, one or both of the following Diagnostic Trouble Codes (DTCs) may be present: ?P1C8449 ? (High Voltage Power Resource Circuit Short during Ready ON) ?P300449 ? (High Voltage Power Resource Circuit Short during Pre-Charge) Follow the Repair Procedure in this bulletin to address this condition.
TSB0085232023-12-26. Service bulletin. ELECTRICAL SYSTEM. TSB: Some 2016 ? 2023 model year Toyota vehicles may exhibit a hybrid system warning lamp occurring in below-freezing temperatures (below 32°F or 0°C). After performing a Health Check, one or both of the following Diagnostic Trouble Codes (DTCs) may be present: ?P1C8449 ? (High Voltage Power Resource Circuit Short during Ready ON) ?P300449 ? (High Voltage Power Resource Circuit Short during Pre-Charge) Follow the Repair Procedure in this bulletin to address this condition.
T-SB-0083-232023-11-27. Service bulletin. ELECTRICAL SYSTEM:INSTRUMENT PANEL:FUEL GAUGE; ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE (ECU/ECM):SOFTWARE; ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL. TSB: Some 2021 ? 2022 model year Sienna Hybrid vehicles may exhibit a condition in which the fuel gauge reading changes when the vehicle is driven up or down an incline and left at an angle of up to 15° for five minutes or longer. The combination meter assembly ECU logic has been modified to reduce the possibility of this condition. Follow the Repair Procedure in this bulletin to reprogram the combination meter assembly ECU.
T-TT-0678-21 Rev2023-11-27. Service bulletin. ELECTRICAL SYSTEM:SOFTWARE. TT: Some 19CY LG DCM equipped vehicles may not be able to complete the firmware update due to not having an active account or waived services during the trial. Follow the steps below to enable ?Temp DCM Activation?.
T-SB-0018-232023-05-15. Service bulletin. ELECTRICAL SYSTEM; ELECTRICAL SYSTEM:PROPULSION SYSTEM:HYBRID MANAGEMENT. TSB: Some 2021 ? 2023 model year Sienna Hybrid vehicles may exhibit a MIL ON condition with Diagnostic Trouble Code (DTC) P060694 (Hybrid/EV Powertrain Control Module Processor Unexpected Operation) present. The Hybrid Vehicle Control Computer logic has been modified to reduce the possibility of this condition.
TT0697222023-05-01. Service bulletin. ELECTRICAL SYSTEM; HYBRID PROPULSION SYSTEM. TT: MIL ON with DTC(s) present for Hybrid/EV Battery Cooling Fan Circuit.
T-SB-0049-21 Rev2023-01-17. Service bulletin. ELECTRICAL SYSTEM; FUEL SYSTEM, GASOLINE. TSB: Some 2020 ? 2022 Highlander and Highlander Hybrid and 2021 ? 2022 Sienna Hybrid vehicles may exhibit a MIL ON condition with Diagnostic Trouble Codes (DTCs) P0087 (Fuel Rail/System Pressure ? Too Low) and/or P107A2A (Fuel Rail Pressure Sensor (Low) Signal Stuck in Range) present. This condition may occur when the vehicle is operated at high altitude and high temperature; typically, above 3,300 feet (1,000 meters) and ambient temperature above 85°F (30°C). The Engine Control Module (ECM) (SAE term: Powertrain Control Module/PCM) logic has been modified to reduce the possibility of this condition occurring. Follow the Repair Procedure in this bulletin to address this condition
TSB008921Rev22022-10-17. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM:BODY CONTROL MODULE/BCM. TSB: Some 2020 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles may exhibit one or more of the following conditions: ?Diagnostic Trouble Code (DTC) B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App does not accept the activation code. ?Toyota App is inoperative. ?SOS call center does not receive the vehicle?s location in a timely manner. ?Toyota App shows an error 42 when trying to execute a command. ?Unable to remote start the vehicle with the key fob (if equipped). ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Destination Assist is inoperative. Some 2020 ? 2021 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles and some 2021 model year Avalon, Avalon Hybrid, Corolla, Corolla Hybrid, Sienna Hybrid, and Venza Hybrid vehicles may exhibit one or more of the following conditions: ?DTC B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App is inoperative. ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Depleted 12V vehicle battery when in IG-OFF. ?Unable to reconnect out of network. A DCM reset and firmware update is now available to address these conditions. Follow the DCM Reset and Firmware Update Procedure in this bulletin to update the firmware.
TSB008921Rev22022-09-15. Service bulletin. ELECTRICAL SYSTEM. TSB: Some 2020 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles may exhibit one or more of the following conditions: ?Diagnostic Trouble Code (DTC) B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App does not accept the activation code. ?Toyota App is inoperative. ?SOS call center does not receive the vehicle?s location in a timely manner. ?Toyota App shows an error 42 when trying to execute a command. ?Unable to remote start the vehicle with the key fob (if equipped). ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Destination Assist is inoperative.
T-SB-0107-20 Rev2022-08-15. Service bulletin. ELECTRICAL SYSTEM. TSB: Flash reprogramming allows the Electronic Control Unit (ECU) software to be updated without replacing the ECU. Flash calibration updates for specific vehicle models/ECUs are released as field-fix procedures described in individual Service Bulletins. This bulletin details the Techstream ECU flash reprogramming process and outlines use of TIS and the Calibration Update Wizard (CUW). To ensure the correct ECU software is installed, ECUs will require a Security Signature before the ECU will initialize the flash reprogramming sequence. This bulletin also details the process for acquiring a Security Signature from TIS during the Techstream ECU flash reprogramming process
T-SB-0110-20 Rev2022-06-13. Service bulletin. ELECTRICAL SYSTEM:PROPULSION SYSTEM:TRACTION BATTERY; EQUIPMENT. TSB: This bulletin includes basic procedures for performing a rescue charge at battery on high voltage (HV) Ni-MH and Li-ion batteries. This bulletin should be used in conjunction with the applicable model and model year Repair Manual while performing the battery rescue charge. The GRX-5100 should be used wherever the Repair Manual references the Toyota Hybrid System (THS) charger
T-TT-0694-222022-05-16. Service bulletin. ELECTRICAL SYSTEM. TT: After jump-starting, the vehicle may experience a no-start condition and multiple DTCs including U010087. Upon investigation, it is found that the engine ECU has been damaged and needs to be replaced (Fig 1). In several cases, it was found that the cause of the ECU damage was improper jump starting. Further investigation found that ECU damage may occur if the jumper cables are hooked up on or around the engine ECU or ECU mounting bracket
T-SB-0003-222022-02-14. Service bulletin. ELECTRICAL SYSTEM:WIRING. TSB This Service Bulletin includes guidelines meant to help determine whether to repair or replace a wire harness assembly based on damage type. This Service Bulletin should be used in conjunction with the applicable model and model year Electronic Wiring Diagram (EWD) and/or Repair Manual.
T-TT-0593-20 Rev2022-02-14. Service bulletin. ELECTRICAL SYSTEM:ADAS:DRIVER MONITORING:SOFTWARE; ELECTRICAL SYSTEM. TT: Some customers may experience the inability to activate Remote Connect or Remote Connect becoming inoperative when attempting to send commands to the vehicle. To simplify the diagnosis of this system and prevent the unnecessary replacement of parts, please refer to the procedure below.
T-TT-0678-212022-01-18. Service bulletin. EQUIPMENT:ELECTRICAL; ELECTRICAL SYSTEM. TT: Some 19CY LG DCM equipped vehicles may not be able to complete the firmware update due to not having an active account or waived services during the trial. Follow the steps below to enable ?Temp DCM Activation?.
T-SB-0104-212022-01-18. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT; ENGINE. TSB: Some 2018 ? 2022 model year Toyota vehicles equipped with an A25A-FKS, A25A-FXS, or M20A-FKS engine may exhibit one or more of the following conditions: ?Milky/Discolored engine oil. ?An ?Oil Pressure Low? warning message on the Multi-information Display (MID). ?A MIL ON condition with Diagnostic Trouble Codes (DTCs) P05202A (Engine Oil Pressure Sensor/Switch "A" Signal Stuck in Range) and/or P052477 (Engine Oil Pressure too low [Severe]). Moisture from blow-by gases condenses and accumulates in the engine oil during short trips in extreme cold weather. When the moisture in the oil freezes, the oil pressure may drop, and the aforementioned warning indicators may display. Follow the procedures in this bulletin to address these conditions.
T-SB-0031-212021-06-21. Service bulletin. ENGINE; ELECTRICAL SYSTEM. TSB: Some 2021 model year Sienna Hybrid LE vehicles may exhibit a condition of inoperative remote functions from the app or key fob, such as remote engine start or door lock/unlock functions. Registering either, or both, the ?Remote Engine Starter Registration Status? and ?Remote Door Lock Function? may be necessary using Techstream to address this condition. Follow the Repair Procedure in this bulletin to address this condition.
T-TT-0650-212021-06-21. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. TT: Some vehicles equipped with Premium Audio systems may experience an inoperative condition that consists of displaying a ?Loading?? then a blank screen when pressing the MAP button. When performing the Storage Check in the Radio Diagnostic Menu, the MEU Storage Check displays: NG.
T-TT-0611-20 Rev2021-06-21. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT:ELECTRICAL:NAVIGATIONAL SYSTEM(GLOBAL POSITIONING SYSTEM). TT: To assist with the early detection and early resolution of audio related concerns, it may be requested as part of the remanufactured head unit return to recover MMR data from the head unit. The following steps are instructions on how to retrieve the data from the system and are only to be used when requested by audio suppliers, FTS, and/or FPEs.
T-TT-0599-20 Rev2021-04-19. Service bulletin. ELECTRICAL SYSTEM; BACK OVER PREVENTION. TT: Vehicle control apps might not operate as expected at times due to preconditions (normal operating parameters) not being established, vehicle settings and/or network/cellular coverage concerns.
T-SB-0095-20 Rev2021-02-16. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY. TSB: Some 2020 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles may exhibit one or more of the following conditions: ?Diagnostic Trouble Code (DTC) B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App does not accept the activation code. ?Toyota App is inoperative. ?SOS call center does not receive the vehicle?s location in a timely manner. ?Toyota App shows an error 42 when trying to execute a command. ?Unable to remote start the vehicle with the key fob (if equipped). ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Destination Assist is inoperative Some 2020 ? 2021 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles and some 2021 model year Avalon, Avalon Hybrid, Corolla, Corolla Hybrid, Sienna Hybrid, and Venza Hybrid vehicles may exhibit one or more of the following conditions: ?DTC B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App is inoperative. ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Depleted 12V vehicle battery when in IG-OFF. Some 2020 ? 2021 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles and some 2021 model year Avalon, Avalon Hybrid, Corolla, Corolla Hybrid, Sienna Hybrid, and Venza Hybrid vehicles may exhibit the following condition: ?Depleted 12V vehicle battery when in IG-OFF. A DCM reset and firmware update is now available to address these conditions. Follow the DCM Reset and Firmware Update Procedure in this bulletin to update the firmware.
T-SB-0095-20 Rev2021-02-16. Service bulletin. ELECTRICAL SYSTEM:12V/24V/48V BATTERY. TSB: Some 2020 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles may exhibit one or more of the following conditions: ?Diagnostic Trouble Code (DTC) B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App does not accept the activation code. ?Toyota App is inoperative. ?SOS call center does not receive the vehicle?s location in a timely manner. ?Toyota App shows an error 42 when trying to execute a command. ?Unable to remote start the vehicle with the key fob (if equipped). ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Destination Assist is inoperative. Some 2020 ? 2021 model year Camry, Camry Hybrid, Corolla Hatchback, RAV4, and RAV4 Hybrid vehicles and some 2021 model year Avalon, Avalon Hybrid, Corolla, Corolla Hybrid, Sienna Hybrid, and Venza Hybrid vehicles may exhibit one or more of the following conditions: ?DTC B15A804 is present in current or history. ?Red SOS LED stays on after bulb check. ?Toyota App is inoperative. ?Unable to subscribe to remote services. ?Unable to activate Wi-Fi. ?Depleted 12V vehicle battery when in IG-OFF. A DCM reset and firmware update is now available to address these conditions. Follow the DCM Reset and Firmware Update Procedure in this bulletin to update the firmware.

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