Audi A1 2011 - Page 161

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Note
♦ Temperature of refrigerant circuit components should be equal
to ambient temperature. Pressure will deviate from values in
table if individual components of refrigerant circuit are warmer
or colder.
♦ At absolute pressure, 0 bar corresponds to absolute vacuum.
Normal ambient pressure (positive pressure) corresponds to
1 bar absolute pressure. 0 pressure corresponds to an abso‐
lute pressure of one bar on most pressure gauges (indicated
by -1 bar below 0).
♦ On vehicles with High pressure sensor -G65- or A/C pressure/
temperature sensor -G395- for which measured pressure is
displayed in measured value block, pressure measured
should coincide using Vehicle Diagnosis, Testing & Informa‐
tion System -VAS5051B- (“OBD“ or “Guided Fault Finding for
the A/C system“) and ⇒ Heating, Ventilation and Air Condi‐
tioning; Rep. Gr. 87 ; Diagnosis and Testing (vehicle-specific
repair manual).
♦ Pressure is measured in different units: 1 MPa (mega Pascal)
corresponds to 10 bar positive pressure or 145 psi, 1 bar ab‐
solute pressure corresponds to 0 bar positive pressure and
thus to the ambient pressure (atmospheric pressure).
Pressure In Refrigerant Circuit Lower Than Indicated In Table
Not enough refrigerant in refrigerant circuit
– Determine refrigerant circuit leaks. Refer to
⇒ “4.2.1 Refrigerant Circuit, Determining Leaks “, page 143 .
– Check pressure relief valve.
If pressure relief valve has responded:
– Check coolant fan activation.
– Check refrigerant pipes and hoses for cross-section constric‐
tions caused by inadequate bending radii.
– Check refrigerant pipes and hoses for external damage.
– If no fault is found, clean refrigerant circuit (flush using refrig‐
erant R134a, refer to
⇒ “1.4.13 Refrigerant Circuit Flushing With Refrigerant
R134a“, page 32 or blow through using compressed air and
nitrogen, refer to
⇒ “1.4.12 Refrigerant Circuit Flushing With Compressed Air
and Nitrogen “, page 29 ).
Pressure In Refrigerant Circuit In Line With Table Or Higher
– Start the engine.
– Set air conditioning system to maximum cooling output.
Note
If the vehicle has a Compressor regulator valve -N280- control
current can be read out in measured value block using Vehicle
Diagnosis, Testing & Information System -VAS5051B- (“OBD“ or
“Guided Fault Finding for the A/C System“) and ⇒ Heating, Ven‐
tilation and Air Conditioning; Rep. Gr. 87 ; Diagnosis and Testing
(vehicle-specific repair manual).
If compressor is not driven with engine running or regulating valve
is not actuated:
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A2 2001 ➤ , A ...
Refrigerant R134a Servicing - Edition 01.2011
4. Diagnosis and Testing 157