Volkswagen Golf / Golf GTI / Jetta. Manual - part 1015

- 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. 

- Not enough refrigerant in 
refrigerant circuit. 

- Extract refrigerant from 
refrigerant circuit. 

- If quantity of refrigerant extracted 
is substantially less than specified 
capacity. 

- Localize leak using leak detector 
and eliminate. 

- Re-charge refrigerant circuit.

- Repeat test. 

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

 

- Expansion valve malfunctioning  - Replace expansion valve.

- Re-charge refrigerant circuit.

- Repeat test. 

Note: 

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

- Check measured values of 
Evaporator Vent Temperature 
Sensor G263 and activation of A/C 
Compressor Regulator Valve 
N280 . If measured value of High 
Pressure Sensor G65 is not OK, 
evaporator may ice up or cooling 
output is not attained. 

- If the function of the air 
conditioning system is not OK 
when the test is repeated after 
replacing expansion valve, re-
install old expansion valve and 
flush refrigerant circuit with 
compressed air and nitrogen. 
Then replace A/C compressor and 

Pressures, checking on vehicles

13/2/2005

receiver. 

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

- If expansion valve is 
malfunctioning (permanently 
closed or does not open 
sufficiently), A/C Compressor 
Regulator Valve N280 is actuated 
to maximum output and low 
pressure drops to value in graph 
or below (compressor draws off 
refrigerant from low-pressure 
side). As however refrigerant 
cannot flow via expansion valve, 
cooling output is not attained and 
high pressure may also not 
increase or only increase slightly 
due to the absence of energy 
conversion. 

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 

- Check activation of 
Compressor Regulator Valve 
N280 . 

 

- A/C compressor malfunctioning.  - Discharge refrigerant circuit.

- Replace compressor. 

- Re-charge refrigerant circuit.

- High pressure increases above 
specification. 

- 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 

- Check activation of 
Compressor Regulator Valve 
N280 . 

 

- Constriction or obstruction in 
refrigerant circuit 

- Run hand over refrigerant circuit 
to check for differences in 
temperature 

- If difference in temperature is 

Pressures, checking on vehicles

13/2/2005

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 

- Re-charge refrigerant circuit.

- Repeat test. 

- If no malfunction can be found:

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Re-charge refrigerant circuit.

- Repeat test, if function is not OK.

 

- Expansion valve malfunctioning  - Discharge refrigerant circuit.

- Replace expansion valve and 
receiver. 

- Re-charge refrigerant circuit.

Note: 

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

- If expansion valve is 
malfunctioning (permanently 
closed or does not open 
sufficiently), A/C Compressor 
Regulator Valve N280 is actuated 
to maximum output and low 
pressure drops to value in graph 
or below (compressor draws off 
refrigerant from low-pressure 
side). As however refrigerant 
cannot flow via expansion valve, 
cooling output is not attained and 
high pressure may also not 
increase or only increase slightly 
due to the absence of energy 
conversion. 

Possible deviation from 

Possible cause

Corrective action

Pressures, checking on vehicles

13/2/2005

specification

- High and low pressure normal at 
first, after some time high pressure 
increases above specification. 

- After a time, low pressure drops 
to value in graph or below. 

- Required cooling output is no 
longer attained. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning 

- Check activation of 
Compressor Regulator Valve 
N280 . 

- High and low pressure normal at 
first, after lengthy driving time, low 
pressure drops below specification 
(evaporator ices up). 

- Moisture in refrigerant circuit 

- Discharge refrigerant circuit.

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Replace receiver with dryer.

- Evacuate refrigerant circuit for at 
least 3 hours. 

- Re-charge refrigerant circuit.

- Repeat test. 

Note: 

- If problem involving moisture in 
refrigerant circuit only occurs after 
a lengthy operating period or only 
infrequently (low pressure drops 
below specification and evaporator 
ices up), it is sufficient to replace 
the dryer in the receiver. Adjust 
quantity of refrigerant oil. 
Refrigerant circuit is then to be 
evacuated for at least 3 hours. 

- It is not initially necessary to 
flush the refrigerant circuit with 
compressed air and nitrogen when 
this problem occurs since 
normally, there is only a small 
quantity of moisture in the system 
which can be removed by lengthy 
evacuation. 

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

Possible deviation from 

specification

Possible cause

Corrective action

Pressures, checking on vehicles

13/2/2005