Volkswagen Golf / Golf GTI / Jetta. Manual — part 1010

caused by inadequate bending
radii.

- Check refrigerant pipes and
hoses for external damage.

- If no fault is found, flush
refrigerant circuit with compressed
air and nitrogen.

Pressure in refrigerant circuit in
line with table or higher.

- Start engine.

- Set air conditioning system to
maximum cooling output.

Note:

- If the low pressure switch was
removed to connect the service
station, bridge the electrical
connections in the corresponding
connector for the pressure
measurement.

- A/C compressor is driven by the
engine via A/C Clutch N25 .

- A/C Compressor Regulator Valve
N280 is activated by Climatronic
Control Module J255 .

Repair Manual, Heating & Air

Conditioning, Repair Group 87 ,

If compressor is not driven with
engine running or regulating
valve is not actuated:

- Establish and eliminate cause
e.g. by checking air conditioner
DTC memory.

- Observe test conditions.

- Check voltage supply for A/C
Clutch N25 , if this is OK, repair
A/C clutch.

- Check activation of A/C

Pressures, checking on vehicles

13/2/2005

Compressor Regulator Valve
N280 .

.

Repair Manual, Heating & Air

Conditioning, Repair Group 87 ,

Continuation of pressure
testing

- Checking pressures for vehicles
with restrictor and reservoir (with
internally regulated compressor)

00-7, Restrictor and reservoir

(with internally regulated
compressor), checking

.

- Checking pressures for vehicles
with expansion valve and receiver
(with internally regulated
compressor)

00-7, Expansion

valve and receiver (with internally
regulated compressor), checking

.

- Checking pressures for vehicles
with expansion valve and receiver
(without internally regulated
compressor)

00-7, Expansion

valve and receiver (without
internally regulated compressor),
checking

.

- Checking pressures for vehicles
with restrictor, reservoir and A/C
Compressor Regulator Valve
N280 (externally regulated
compressor)

00-7, Restrictor,

reservoir and A/C Compressor
Regulator Valve N280 (externally
regulated compressor), checking

.

Restrictor and reservoir
(with internally regulated
compressor), checking

Note:

- Connect service station

00-6,

Service station, connecting

.

Pressures, checking on vehicles

13/2/2005

- 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
refrigerant circuit switches are
vehicle-specific.

- Connection with valve for low-
pressure switch or at evaporator is
only to be used for vehicles with
no service connection on low-
pressure side and an inaccessible
connection at compressor or
reservoir (measurement
accuracy). Only applies to certain
vehicles.

Repair Manual, Heating & Air

Conditioning, Repair Group 87 ,

Specified values:

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 (measured at
service connection) in bar

B - Low pressure (measured at
connection with valve at
compressor or reservoir) in bar.

C - Permissible tolerance range.

Pressures, checking on vehicles

13/2/2005

D - Low pressure (measured at
connection with valve for low-
pressure switch or at service
connection) in bar.

E - 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
refrigerant circuit.

- 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.

Note:

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

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.

A/C compressor
malfunctioning.

- Flush refrigerant circuit with
compressed air and nitrogen.

- Replace compressor.

- High pressure increases above
specification

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

- Required cooling output is not
attained.

Pressures, checking on vehicles

13/2/2005