Volkswagen Golf / Golf GTI / Jetta. Manual - part 1014

low" , note the following: If 
malfunctioning, evaporator may 
ice-up or cooling output is not 
reached. 

- With this malfunction, evaporator 
may ice up although quantity of 
refrigerant in circuit is OK. 

- Check measured values of 
Evaporator Vent Temperature 
Sensor G263 . 

- Check activation of A/C 
Compressor Regulator Valve 
N280 

 
 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

Possible deviation from 

specification

Possible cause

Corrective action

- High pressure normal or too high 

- Low pressure too high (see 
graph), 

- Compressor noise (particularly 
after switch-on) 

- Required cooling output is not 
attained. 

- Too much refrigerant in circuit 

- Extract refrigerant from 
refrigerant circuit. 

- If quantity of refrigerant extracted 
roughly corresponds to specified 
capacity: 

- Replace A/C compressor.

- If quantity of refrigerant extracted 
is substantially greater than 
specified capacity: 

- Re-charge refrigerant circuit.

- Repeat test. 

- High and low pressure normal 

- Required cooling output is not 
attained. 

- Too much refrigerant in circuit 

- Discharge refrigerant circuit.

- Flush refrigerant circuit with 
compressed air and nitrogen.

- High and low pressure normal 

- Compressor noise (particularly 
after switch-on) 

- The required cooling level is 
obtained. 

 

 

Pressures, checking on vehicles

13/2/2005

Note: 

- Overfilling with refrigerant oil can 
occur if, for example, the 
compressor has been replaced 
without adjusting the quantity of 
refrigerant oil. 

Expansion valve, receiver 
and A/C Compressor 
Regulator Valve N280 
(externally regulated 
compressor), checking 

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. 

- Pressures must be measured at 
service connections; component 
locations of these connections are 
vehicle-specific 

 
 

. 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

 
 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

Specified values:

 

Pressures, checking on vehicles

13/2/2005

  

 

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 
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 measured by High 
Pressure Sensor G65 is displayed 
in measured value block 

 
 

. 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

Pressures, checking on vehicles

13/2/2005

- 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. 0.65 A up to 0.85 A 
(vehicle specific, displayed in 
measured value block) 

 
 

. 

 Repair Manual, Heating & Air 

Conditioning, Repair Group 87 , 

- 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. 

 

 

Pressures, checking on vehicles

13/2/2005