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Hissing from vents and slow loss of refrigerant

Q: How to fix Hissing from vents and slow loss of refrigerant in Toyota Tundra?

Stripping the entire dashboard down to nothing. Replacing the wax evaporator with a modernized one AND installing a new chemical-resistant drain hose. Ozonation and carpet drying. It's a workshop nightmare and a mighty TSB (T-SB-0021-23). If you have a 3-year-old RAV4 and water on the mats, don't let yourself get putty on a leaky window. Contact the dealership and refer to the bulletin about evaporator wax while the car is subject to claims.

in Toyota Tundra (2020-2022)

Symptoms

Irregular A/C operation

DTC error codes

Brak

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Technical diagnosis (Premium)

Recognized technical fault:

Auxiliary controller voltage instability detected

Technical analysis

Detailed analysis of HVAC controller operation parameters, CAN bus data readings, and diagnostic signal waveforms. Purchase PRO access or log in to read the full fault analysis.

Confirmed solution

Complete step-by-step repair procedure including module non-volatile memory reset, sensor calibration, and correct wiring routing. Unlock the full report to see the instruction.

Parts needed

Filters ferrite anti-interference / noise suppressor
Auxiliary starting battery (depending on cell status)

Workshop hacks

Important workshop tips for mechanics regarding bypasses without expensive control module replacement and manufacturer software service bulletins.

TSB / TPI service bulletins

TSB-24-HVAC-01TPI-2068943/2

A/C Technical Specifications

Refrigerant specifications for this model are available in the catalog.

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Hissing from vents and slow loss of refrigerant

Symptoms

DTC error codes

A/C Technical Specifications

Other problems in Tundra

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