Toyota Sienna Hybrid 2021 — technical service bulletin
Bulletin T-SB-0016-21 · NHTSA communication 10190469 · issued Mar 31, 2021
Technical service bulletin
communication type
Power Train
component
2021
model years
1
vehicle entries
Official summary
TSB: Some 2021 model year Sienna Hybrid vehicles may exhibit a depleted 12V auxiliary battery when in IG-OFF due to a condition in which the Hybrid Vehicle Electronic Control Unit (HV ECU) does not sleep. The HV ECU may not sleep if any of the following have occurred with the vehicle: ? The vehicle was towed or jump-started after a 12V battery discharge. ? The vehicle?s 12V battery was disconnected and reconnected, as when accessories were installed. ? The 12V battery terminal(s) or power or ground harnesses were removed to repair the vehicle. ? A new 12V battery was put into the vehicle, or t
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.