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Air conditioning stopped cooling / no response to AC button

Q: What are the symptoms of Air conditioning stopped cooling / no response to AC button in Kia Carnival (KA4)?

Problem visible at standstill or in traffic. Problem appears while driving. Air conditioning does not turn on

Q: How to fix Air conditioning stopped cooling / no response to AC button in Kia Carnival (KA4)?

KDS diagnostics (Max AC for 5 minutes). If the temperature on the evaporator increases/fluctuates - replace the complete compressor according to action SA632. The fault is detected even in cars from the dealership before sale (TSB SA632). New Carnival? Measure the temperature on the grill at the lowest fan speed.

in Kia Carnival (KA4) (2025-2026)

Symptoms

Problem visible at standstill or in traffic
Problem appears while driving
Air conditioning does not turn on

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

Standard

Refrigerant: R134a Amount (g): 775 – 825g Oil: ND8 PAO 68 lub PAG ISO 46 Oil (ml): 110 – 130ml

2,5 i GV6

Refrigerant: R134a Amount (g): 1000g Oil: ND8 PAO 68 lub PAG ISO 46 Oil (ml): 200ml

Standard

Refrigerant: R134a Amount (g): 1150g Oil: PAG PAO 68 lub PAG ISO 46 Oil (ml): 200ml

See full specification

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