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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 Mazda 3?

Replacement of the air conditioning evaporator with a new, modified part with an improved design of tube connections. Repair requires complete disassembly of the dashboard (time-consuming procedure). After replacement, top up the compressor oil (approx. 40 ml) and fill the system with fresh refrigerant in accordance with the specifications.

in Mazda 3 (2013-2023)

Symptoms

No cold air from vents

DTC error codes

Low Pressure Fault

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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

(BP)

Refrigerant: R1234yf Amount (g): 420-470g Oil: PAG YF ISO 46 Oil (ml): 110 - 140ml

See full specification

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Hissing from vents and slow loss of refrigerant

Symptoms

DTC error codes

A/C Technical Specifications

Other problems in 3

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