Volkswagen Golf 1999 Service Manual page 4052

Pressures, checking on vehicles
Possible deviation from
specification
- High pressure only increases
slightly above pressure with
engine stopped,
- Low pressure only drops slightly,
- Required cooling output is not
attained.
- High pressure increases above
specification
- Low pressure only drops slightly,
- Required cooling output is not
attained.
- High and low pressure normal at
first, after some time high pressure
increases above specification and
- Low pressure quickly drops to
value in graph or below,
- Required cooling output is no
longer attained.
- High pressure normal,
- Low pressure too low (see
graph),
- The required cooling level is
obtained.
Note:
- For the malfunction "high
pressure normal, low pressure too
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Possible cause
- Activation of A/C Compressor
Regulator Valve N280
malfunctioning
- A/C compressor malfunctioning.
- Constriction or obstruction in
refrigerant circuit
- Moisture in refrigerant circuit
- Activation of A/C Compressor
Regulator Valve N280
malfunctioning
- A/C compressor malfunctioning.
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Corrective action
- Check activation of
Compressor Regulator Valve
N280 .
- Flush refrigerant circuit with
compressed air and nitrogen.
- Replace compressor.
- Run hand over refrigerant circ
to check for differences in
temperature
- If difference in temperature is
found at one component:
- If hose or pipe is kinked or
constricted, replace this
component.
- In the event of an obstruction
flush refrigerant circuit with
compressed air and nitrogen
- If no malfunction can be found
- Flush refrigerant circuit with
compressed air and nitrogen.
- Flush refrigerant circuit with
compressed air and nitrogen.
- Check activation of
Compressor Regulator Valve
N280 .
- Flush refrigerant circuit with
compressed air and nitrogen.
- Replace compressor.
13/2/2005