Volkswagen Golf / Golf GTI / Jetta. Manual - part 1016

- High pressure normal, low 
pressure too low (see graph), 
required cooling output attained. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning. 

- Check activation of 
Compressor Regulator Valve 
N280 . 

 

- Expansion valve or compressor 
malfunctioning. 

- Discharge refrigerant circuit.

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Replace expansion valve and 
receiver. 

- Re-charge refrigerant circuit.

- Repeat test, if function is not OK.

 

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

- Replace A/C compressor.

- Re-charge refrigerant circuit.

- Repeat test. 

Note: 

- For the malfunction "high 
pressure normal, low pressure too 
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 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 problem is with the A/C 
Compressor Regulator Valve 
N280 (regulating valve is not 
actuated but compressor operates 
nevertheless), refrigerant circuit 
does not have to be flushed. It is 
sufficient in this case to replace 
the compressor (adjust quantity of 

Pressures, checking on vehicles

13/2/2005

refrigerant oil in compressor). 

- 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. 

 
 

 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. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning. 

- Too much refrigerant in circuit 

- Check activation of 
Compressor Regulator Valve 
N280 . 

- 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. 

 

- Too much refrigerant in circuit 

- Discharge refrigerant circuit.

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

Pressures, checking on vehicles

13/2/2005

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Re-charge refrigerant circuit.

- Repeat test. 

 

- Expansion valve or compressor 
malfunctioning. 

- Discharge refrigerant circuit.

- Replace expansion valve and 
receiver. 

- Re-charge refrigerant circuit.

- Repeat test, if function is not OK.

- Replace A/C compressor.

 

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

- Replace A/C compressor.

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

- Re-charge refrigerant circuit.

- Repeat test. 

Note: 

- If the problem is with the A/C 
Compressor Regulator Valve 
N280 (regulating valve is not 
actuated but compressor operates 
nevertheless), refrigerant circuit 
does not have to be flushed. It is 
sufficient in this case to replace 
the compressor (adjust quantity of 
refrigerant oil in compressor). 

- 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 

Pressures, checking on vehicles

13/2/2005

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 and low pressure normal. 

- Required cooling output is not 
attained. 

- Activation of A/C Compressor 
Regulator Valve N280 
malfunctioning. 

- Too much refrigerant in circuit 

- Check activation of 
Compressor Regulator Valve 
N280 . 

- 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. 

- Too much refrigerant in circuit 

- Discharge refrigerant circuit.

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Re-charge refrigerant circuit.

- Repeat test. 

 

- Expansion valve malfunctioning  - Replace expansion valve.

Note: 

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

- If expansion valve is 
malfunctioning (permanently 
open), evaporator temperature is 
no longer regulated such that only 
refrigerant in gas form exits from 
the evaporator. Under certain 
usage conditions, liquid droplets 
may then be drawn in by the 
compressor and cause noise 
(liquid cannot be compressed). 

Pressures, checking on vehicles

13/2/2005