Toyota Tundra 2018–2021 — technical service bulletin
Bulletin T-TT-0661-21 · NHTSA communication 10201395 · issued Jul 21, 2021
Technical service bulletin
communication type
Equipment
component
2018–2021
model years
4
vehicle entries
Official summary
TT: Customer complaint of HVAC compressor ?Bang? type noise upon initial compressor engagement when air conditioning has not been operated for an extended period (~24 hrs. or longer). The noise is caused by compressor oil collecting in the compressor and upon initial compressor engagement, the compressor must pump the oil out causing the ?Bang? noise. Compressor engagements thereafter are normal and less audible as the collected oil has been pumped out.
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.