Volkswagen Golf / Golf GTI / Jetta. Service manual - part 1013

  

Note: 

- Connect service station 

 

00-6, 

Service station, connecting

 . 

- Observe test conditions 

 

00-7, 

Pressures, checking on vehicles

 . 

- Set engine speed to 2000 RPM. 

- Observe pressure gauge of 
service station. 

Note: 

- Switching pressures for actuation 
of A/C Compressor Regulator 
Valve N280 and Coolant Fan V7 
are vehicle-specific. 

 
 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

Specified values:

 

 

High pressure side:

 

Increasing from initial pressure (on 
connecting pressure gauges) to 20 
bar.

 

Low pressure side:

 

Decreasing from initial pressure 
(on connecting pressure gauges) 
to value in graph.

A - Low pressure (measured at 
service connection) in bar 

Pressures, checking on vehicles

13/2/2005

absolute 

B - Control current for A/C 
Compressor Regulator Valve 
N280  

C - Permissible tolerance range. 

Note: 

- Under unfavorable conditions 
(very high ambient temperatures, 
high humidity), pressure on high-
pressure side may increase to 
max. 29 bar. 

- Control current - B - is displayed 
in measured value block. 

- High pressure is displayed in 
measured value block 

 
 

. 

 Repair Manual, , Repair Group 

87, 

- Low pressure settles as a 
function of control current for A/C 
Compressor Regulator Valve 
N280 within compressor output 
range in tolerance range. 

- Under unfavorable conditions 
(very high ambient temperatures, 
high humidity), compressor output 
may not always be sufficient to 
attain the specified value. 

- The specified operating current 
for the regulating valve must be 
greater than 0.3 A in order to 
ensure reliable valve actuation. 

- In the setting "maximum cooling 
output" control current is regulated 
to approx. 0.8 A (displayed in 
measured value block) 

 
 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

Pressures, checking on vehicles

13/2/2005

. 

- At absolute pressure, 0 bar 
corresponds to absolute vacuum. 
Normal ambient pressure equals 1 
bar absolute pressure. 0 pressure 
corresponds to an absolute 
pressure of one bar on most 
pressure gauges (indicated by -1 
bar below 0). 

Possible deviation from 

specification

Possible cause

Corrective action

- High pressure remains constant 
or only increases slightly (above 
pressure with engine stopped), 

- Low pressure quickly drops to 
value in graph or below, 

- Required cooling output is not 
attained. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning 

- Not enough refrigerant in 
refrigerant circuit. 

- Check activation of 
Compressor Regulator Valve 
N280 . 

- Localize leak using leak detector 
and eliminate. 

- Re-charge refrigerant circuit.

- High pressure normal, 

- Low pressure in line with value in 
graph, 

- Required cooling output is not 
attained. 

 

 

- High pressure normal, 

- Low pressure too low (see 
graph), 

- Required cooling output is not 
attained. 

- High pressure normal, 

- Low pressure too low (see 
graph), 

- Required cooling output is not 
attained. 

 

 

Note: 

- If no malfunction is found in 
relation to this complaint, flush 
refrigerant circuit with compressed 
air and nitrogen. 

Pressures, checking on vehicles

13/2/2005

Possible deviation from 

specification

Possible cause

Corrective action

- High pressure only increases 
slightly above pressure with 
engine stopped, 

- Low pressure only drops slightly, 

- Required cooling output is not 
attained. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning 

- A/C compressor malfunctioning. 

- Check activation of 
Compressor Regulator Valve 
N280 . 

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Replace compressor. 

- High pressure increases above 
specification 

- Low pressure only drops slightly, 

- Required cooling output is not 
attained. 

- Constriction or obstruction in 
refrigerant circuit 

- Run hand over refrigerant circuit 
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.

- 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. 

- Moisture in refrigerant circuit 

- Flush refrigerant circuit with 
compressed air and nitrogen.

- High pressure normal, 

- Low pressure too low (see 
graph), 

- The required cooling level is 
obtained. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning 

- A/C compressor malfunctioning. 

- Check activation of 
Compressor Regulator Valve 
N280 . 

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Replace compressor. 

Note: 

- For the malfunction "high 
pressure normal, low pressure too 

Pressures, checking on vehicles

13/2/2005