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A/C cooling is weak and gradually loses performance

Q: How to fix A/C cooling is weak and gradually loses performance in Renault Megane 4?

Nitrogen test with foaming solution around the seal at the bottom. Replacement of the condenser and a new O-ring on the lower cable. This is so common in Qashqai J11s that when one arrives in the driveway without air conditioning, you can blindly order a condenser with new O-rings. Don't solder these coolers, they will rot completely.

in Renault Megane 4 (2013-2022)

Symptoms

A/C cooling is weak and gradually loses performance

DTC error codes

Brak (Brak gazu)

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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 - (BFB)

Refrigerant: R1234yf Amount (g): 430-480g Oil: PAG YF ISO 46 Oil (ml): 120 - 140ml

III

Refrigerant: R134a Amount (g): 480g Oil: SP 10 PAO 68 lub PAG ISO 46 Oil (ml): 120ml

II (XMO) 1,4 i/1,5 D dCi/1,6 i/1,9 D dCi/2,0 i/2,0 dCi

Refrigerant: R134a Amount (g): 550g Oil: Planetelf PAG 488 PAO 68 lub PAG ISO 150 Oil (ml): 150ml

See full specification

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