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A/C cooling is weak and gradually loses performance

Q: What are the symptoms of A/C cooling is weak and gradually loses performance in Renault Megane (II/III)?

Irregular A/C operation. No blowing from vents. Air conditioning does not turn on. Vibrations or humming after turning on A/C

Q: How to fix A/C cooling is weak and gradually loses performance in Renault Megane (II/III)?

Improving the contacts (bending the pins) in the compressor and pressure switch plugs, or cutting off the old plugs and soldering new 'repair kits with cable'. After repair, it is necessary to unlock the BSI Clip. If the car arrives with the air conditioning not working, the factor is normal (e.g. 50-100%), and the computer shows a clutch or pressure switch error: BEFORE you replace the pressure switch or compressor, unplug the plugs, use a needle to bend the 'female' plates inside the plug and spray with the contact. In 80% of cases this solves the problem, but remember that you have to reset the error in the computer (Clip), otherwise the air conditioning will not start anyway!

in Renault Megane (II/III) (2003-2016)

Symptoms

Irregular A/C operation
No blowing from vents
Air conditioning does not turn on
Vibrations or humming after turning on A/C

DTC error codes

Pressure sensor faults (Pressure switch)

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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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