Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
A/C refrigerant system, checking pressures: Notes
Safety measures, see A/C SYSTEM, SAFETY PRECAUTIONS .
Before checking refrigerant system pressures, check A/C system cooling performance. See A/C SYSTEM COOLING PERFORMANCE, TESTING .
Use high pressure service valve for checking system pressures.
Test requirements
- Condenser and radiator clean and free of obstructions (clean if necessary)
- Drive belts for compressor and generator in good condition and properly tensioned
- All air ducts, covers and seals OK and correctly installed
- Check DTC memory using VAG 1551 scan tool and eliminate/repair any malfunctions indicated (not affecting A/C system)
- All air distribution flaps reach end positions Engine at normal operating temperature
- Evaporator housing and heater box do not leak air (draw in secondary air) at high fresh air blower speed
- Outside (ambient) temperature must be between 15-45° C (59-113° F)
- Engine running and system set to maximum cooling (AUTO operating mode with LO temperature setting selected):
- Switch compressor on (warning light in ECON button does not light up)
- Temperature selection LO (for driver and passenger side) If the compressor is activated (A/C clutch is switched on):
- Fresh air blower -V2- runs
- Coolant fan -Ml- runs (at least in 1st speed)
- Air flow flap closes and fresh air/recirculated air flap opens (within 1 minute after starting vehicle)
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.