Volkswagen Golf / Golf GTI / Jetta. Manual - part 1011

 

- High and low pressure normal at 
first, after some time,

- High pressure increases above 
specification

- 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 
low" , note the following: 

- This malfunction may cause the 
evaporator to ice up or the A/C 
Refrigerant Low Pressure Switch 
F73 to shut off the compressor 
although the amount of refrigerant 
in the circuit is OK. 

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 

Too much 
refrigerant in 
circuit

- Extract refrigerant from 
refrigerant circuit. 

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

- Replace A/C compressor. 

Pressures, checking on vehicles

13/2/2005

attained. 

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

- Re-charge refrigerant circuit. 

- Repeat test. 

Note: 

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

Expansion valve and 
receiver (with internally 
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 set. 

Note: 

- Switching pressures and 
arrangement of refrigerant circuit 
switches 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 , 

Specified values:

 

 

Pressures, checking on vehicles

13/2/2005

  

 

 

High pressure side:

 

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

 

Low pressure side:

 

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

A - High pressure in bar 

B - Low pressure in bar 

C - Permissible tolerance range. 

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. 

Not enough 
refrigerant in 
circuit or 
expansion valve 
malfunctioning.

- Extract refrigerant from 
refrigerant circuit. 

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

- Replace expansion valve. 

- Re-charge refrigerant circuit. 

- Repeat test. 

- High pressure normal, 

- Low pressure in line with value in 
graph, 

- Required cooling output is not 
attained. 

 

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

- Localize leak using leak detector 
and eliminate. 

- Re-charge refrigerant circuit. 

- Repeat test. 

Note: 

- If no malfunction can be found 
and air conditioner operation is not 
OK when test is repeated, flush 
refrigerant circuit with compressed 
air and nitrogen. 

Possible deviation from 

Possible cause

Corrective action

Pressures, checking on vehicles

13/2/2005

specification

- High pressure increases above 
specification 

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

- Required cooling output is not 
attained. 

- Constriction or obstruction in 
refrigerant circuit 

- Expansion valve malfunctioning 

- 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 and 
replace expansion valve

- If no malfunction can be found:

- Flush refrigerant circuit with 
compressed air and nitrogen.

- Repeat test. 

Note: 

- If operation is not OK after 
refrigerant circuit has been 
flushed, expansion valve must be 
replaced. 

Possible deviation from 

specification

Possible cause

Corrective action

- High and low pressure normal at 
first 

- After some time, high pressure 
increases above specification and 
low pressure drops to value in 
graph or below 

- Required cooling output is no 
longer attained. 

- Expansion valve malfunctioning 

- Moisture in refrigerant circuit 

- Examine expansion valve for dirt 
or corrosion; replace if necessary.

- Flush refrigerant circuit with 
compressed air and nitrogen.

Note: 

- Always replace receiver for this 
malfunction. 

Possible deviation from 

specification

Possible cause

Corrective action

- High pressure normal or too high  - Too much refrigerant in circuit 

- Extract refrigerant from 

Pressures, checking on vehicles

13/2/2005