High Priority 90% confidence

Hissing from vents and slow loss of refrigerant

Q: How to fix Hissing from vents and slow loss of refrigerant in Kia Sorento IV?

Dismantling the entire cockpit with the dashboard and replacing the evaporator (10 hours' work). Terrible news for workshops and your wallet (outside the warranty, about PLN 3-4,000). Without a camera with a UV lamp under the passenger footwell, you wouldn't even guess that dye is leaking there.

in Kia Sorento IV (2021-2023)

Symptoms

Irregular A/C operation

DTC error codes

Low Pressure

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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

IV - (MQ4)

Refrigerant: R1234yf Amount (g): 550-600g Oil: PAG YF ISO 46 Oil (ml): 140 - 170ml

III (UM)

Refrigerant: R1234yf Amount (g): 650g Oil: PAG YF PAO 68 AA1 lub PAG ISO 46 YF Oil (ml): 130ml

III (UM)

Refrigerant: R134a Amount (g): 700g Oil: PAG PAO 68 AA1 lub PAG ISO 46 Oil (ml): 130ml

See full specification

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