Audi Q7: A/C Compressor Regulator Valve -N280-, Removing and Installing
Note
- Certain functions on the A/C Compressor Regulator Valve
-N280- (for example, a stuck valve or a disruption in the coil)
can lead to a complaint regarding the A/C compressor (A/C system
doesn't cool, the evaporator ices over, etc.). If the cause is
with the A/C Compressor Regulator Valve -N280- (and not the A/C
compressor itself), the A/C compressor can be serviced by
replacing the A/C Compressor Regulator Valve -N280--C
and D-.
- The A/C Compressor Regulator Valve -N280--C
and D- is not available as a replacement part for all A/C
compressors. If the A/C Compressor Regulator Valve -N280- is not
available as an individual A/C compressor part, then the entire
A/C compressor must be replaced. Refer to the Parts Catalog.
- The A/C Compressor Regulator Valve -N280- is available in
different versions and settings. Refer to the Parts Catalog. On
the A/C compressor -A- (shown is an
A/C compressor manufactured by "Denso" without an A/C Clutch
-N25-), the connector for the vehicle wiring harness connection
is attached with a short wiring harness to the A/C Compressor
Regulator Valve -N280--C-. On the
A/C compressor -B- (shown is an A/C
compressor manufactured by "Sanden"), the connector for the
vehicle wiring harness connection is mounted directly on the A/C
Compressor Regulator Valve -N280--C-.
The removal and installation of the A/C Compressor Regulator
Valve -N280--C and D- on other A/C
compressors (other type and manufacturer) is basically the same
and only slightly deviates from the procedure described below.
- The A/C Compressor Regulator Valve -N280- is available in
different versions and settings. Refer to the Parts Catalog. On
an A/C Compressor with an A/C Clutch -N25- (shown is an A/C
compressor manufactured by "Denso"), the connector for the
vehicle wiring harness connection is mounted directly on the A/C
Compressor Regulator Valve -N280--A-.
On another A/C compressor, the connector for the vehicle wiring
harness connection is combined in a 3-pin connector
-E- for the A/C Clutch -N25- and
the A/C Compressor Regulator Valve -N280-.
- For version -B- of the A/C
Compressor Regulator Valve -N280-, the wire connection may be
directly connected to the A/C Compressor Regulator Valve -N280-,
or there is an additional connector on the A/C Compressor
Regulator Valve -N280-.
- Removing and installing the A/C Compressor Regulator Valve
-N280--A and B- is essentially the
same on both versions. It only deviates slightly from the
procedure described below. On an A/C compressor with a 3-pin
connector -E-, disconnect the
respective wires to the A/C Compressor Regulator Valve -N280-
from the A/C Compressor Regulator Valve -N280-, remove from the
connector -E- or cut at a suitable
location (and reattach using wire connectors from the Wiring
Harness Repair Set -VAS1978B-).
- If the A/C Compressor Regulator Valve -N280- malfunction was
found to be caused by dirt, shavings or abraded A/C compressor
material after the removal of the A/C Compressor Regulator Valve
-N280-, clean the refrigerant circuit and replace the A/C
compressor. Refer to
→ Chapter "Compressor, Replacing on Account of Leakage or
Internal Damage" and
→ Chapter "Refrigerant Circuit, Cleaning (Flushing), with
Refrigerant R134a".
Removing
- Discharge the refrigerant circuit. Refer to
→ Chapter "Using Service Station".
Caution
There is a risk of damaging the A/C compressor if
the refrigerant circuit is empty.
Do not start the motor if the refrigerant circuit is
empty.
- Depending on the version of the A/C Service Station,
the pressure of the refrigerant circuit may be less than
1 bar (14.5 psi) absolute pressure after it has been
discharged.
- Depending on the version of the A/C compressor, it
may be damaged if the pressure in the refrigerant
circuit is too low.
- Do not start the engine while the refrigerant
circuit pressure is less than the ambient pressure.
- Depending on the vehicle and installed location of the A/C
compressor, remove the components that prevent access to the A/C
Compressor Regulator Valve -N280-. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
On vehicles where at least one of the two refrigerant lines
and the A/C Compressor Regulator Valve -N280- cannot be
disconnected and removed while the A/C compressor is attached to
the engine.
- Remove the A/C compressor. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; A/C
Compressor (vehicle-specific repair manual).
Note
A refrigerant line must be removed on an installed A/C
compressor so that it is assured, that the pressure in the A/C
compressor is the same as the ambient pressure.
On a vehicle, where at least one of the two refrigerant
lines and the A/C Compressor Regulator Valve -N280- can be
disconnected and removed while the A/C compressor is attached to
the engine (the A/C compressor is not removed).
WARNING
There is a danger of ice-up.
- Before removing the A/C Compressor Regulator Valve
-N280-, connect the service station and extract the
refrigerant. Refrigerant circuit must be empty to avoid
possible injury.
- Refrigerant and refrigerant oil will leak out if the
refrigerant circuit is not discharged.
- The refrigerant is extracted before removing the A/C
Compressor Regulator Valve -N280-. If the A/C Compressor
Regulator Valve -N280- is not removed within 10 minutes
after extraction, pressure may build up in the
refrigerant circuit by renewed evaporation. Extract the
refrigerant once more.
- Check the pressure in the refrigerant circuit once more via
the A/C service station pressure gauge.
- If the displayed pressure is larger than the ambient
pressure (larger than approximately 1 bar (14.5 psi) absolute
pressure), turn on the A/C service station and extract the
refrigerant that is building up the pressure.
- Disconnect one of the two refrigerant lines from the A/C
compressor. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
Note
A refrigerant line must be removed on an installed A/C
compressor so that it is assured, that the pressure in the A/C
compressor is the same as the ambient pressure.
All vehicles
- Before removing the A/C Compressor Regulator Valve -N280-
check again if the A/C compressor is actually being driven by
the belt pulley/drive unit. If the belt pulley or the drive unit
overload protection has triggered, the cause for the fault is
not the regulator valve but rather the A/C compressor (for
example does not move easily).
Note
- This illustration shows the A/C Compressor Regulator Valve
-N280--B- on a A/C compressor
manufactured by "Sanden" type "PXE 14". On these A/C compressors
the connector to the vehicle wiring harness connection is
mounted directly on the A/C Compressor Regulator Valve -N280--B-.
The removal and installation of the A/C Compressor Regulator
Valve -N280--B- on other A/C
compressors (other type and manufacturer, for example "Denso",
the A/C Compressor Regulator Valve -N280- with a short wiring
harness, for example) can differ. The procedure for removal and
installation is however the same, as described in the following
for the A/C compressor manufactured by "Sanden" type "PXE 14".
- This illustration shows an A/C Compressor Regulator Valve
-N280--B- with an O-ring
-E- (not available on all
versions).
- On a A/C Compressor Regulator Valve -N280--B-
without an O-ring -E-, dirt can
penetrate into the A/C Compressor Regulator Valve -N280--C-
mount up to the O-ring -F-.
- If applicable, loosen the wire connection from the A/C
Compressor Regulator Valve -N280--B-
to the connection to the vehicle wire harness from the A/C
compressor.
Note
- On an A/C compressor with an A/C Clutch -N25- where the A/C
Clutch -N25- is activated via the same connector as the A/C
Compressor Regulator Valve -N280--B-,
remove the applicable wires from the connector (for example,
using an extractor from the Wiring Harness Repair Set
-VAS1978B-). Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
- If a connector should be installed on an A/C compressor with
an A/C Clutch -N25- where the wires cannot be removed, cut the
wires to the A/C Compressor Regulator Valve -N280- (or to the
A/C Clutch -N25-) at a suitable location and reattach using wire
connectors from the Wiring Harness Repair Set -VAS1978B- (or
replace the connector itself. Refer to the Parts Catalog). Refer
to
→ Electrical Equipment; Rep. Gr.97; Connectors; Wiring Harnesses
and Connectors, Repairing.
- Clean the A/C compressor near the circlip
-A- and the A/C Compressor
Regulator Valve -N280--B-
thoroughly.
Caution
The pressure in the A/C compressor must be equal to
the ambient pressure.
- Refrigerant and refrigerant oil can leak out if
there is excess pressure in the A/C compressor.
- Dirt can be absorbed into the A/C compressor if
there is a vacuum in the A/C compressor.
- Make sure there is pressure equalization before
removing the A/C Compressor Regulator Valve -N280--B-.
- Remove the circlip -A-.
- Carefully remove the A/C Compressor Regulator Valve -N280--B-
from the A/C compressor mount -C-,
using a suitable screwdriver -D-,
for example.
- Check the removed A/C Compressor Regulator Valve -N280--B-
and A/C compressor mount -C- for
dirt.
Note
- If the strainer -D-, A/C
Compressor Regulator Valve -N280--B-
up to the O-ring -F- or the A/C
compressor mount -C- are heavily
contaminated in this area (with shavings or dark, sticky abraded
material, for example), this indicates damage on the A/C
compressor. In this case, the refrigerant circuit is to be
cleaned and the A/C compressor is to be replaced. Refer to
→ Chapter "Compressor, Replacing on Account of Leakage or
Internal Damage" and
→ Chapter "Refrigerant Circuit, Cleaning (Flushing), with
Refrigerant R134a".
- If the strainer -D- on the A/C
Compressor Regulator Valve -N280--B-
and the A/C compressor mount -C- up
to the O-ring sealing surface -F-
are only lightly contaminated in this area (with gray deposits
from normal A/C compressor operation, for example), a
malfunction at the A/C Compressor Regulator Valve -N280--B-
can cause the A/C compressor malfunctioning.
- On an A/C Compressor Regulator Valve -N280--B-
without an O-ring -E-, dirt can
penetrate into the mount -C- up to
the O-ring -E- during operation.
Remove the dirt carefully and completely using, for example, a
lint-free cloth (do not work with compressed air).
Installing
- Check the A/C compressor mount -C-
and the circlip groove for dirt, and if necessary, clean them
carefully and thoroughly with a clean, lint-free cloth.
Caution
Danger of another A/C Compressor Regulator Valve
-N280--B- or A/C compressor
failure due to dirt in the A/C compressor or damage to
the sealing surfaces in the mount.
- If necessary, carefully clean the A/C compressor
mount -C- using only a
clean, lint-free cloth (do not use compressed air).
- Make sure while cleaning the mount
-C- that no dirt gets into
the area underneath the O-ring sealing surface
-F- or the existing
channels and none of the mount sealing surfaces become
damaged.
- Check the A/C compressor mount -C-
for damage (also pay attention to small scratches on the
surface, if there is damage, replace the A/C compressor).
- Check the O-rings -F,G and H-
and -E- (if applicable) of the A/C
Compressor Regulator Valve -N280--B-
for damage.
- Coat the O-rings -F, G and H-
and -E- (if applicable) of the A/C
Compressor Regulator Valve -N280--B-
lightly with refrigerant oil and check for proper seating.
- Insert the A/C Compressor Regulator Valve -N280--B-
until the stop in the A/C compressor mount
-C-.
- Install the new circlip -A- and
check for proper seating in the groove.
- Install the removed parts in the opposite order.
- Evacuate and refill the refrigerant circuit. Refer to
→ Chapter "Using Service Station".
Note
Should refrigerant oil escape with the A/C Compressor
Regulator Valve -N280--B- removed,
add this amount of refrigerant oil while filling the refrigerant
oil with the A/C service station. Refer to
→ Chapter "Using Service Station".
- Check the A/C function. Refer to
→ Chapter "Pressures, Checking" and
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
READ NEXT:
Approved Refrigerant Oils and Capacities
Note
As PAG (polyalkylene glycol) oil is highly hygroscopic
(attracts water), opened containers are to be immediately
resealed so as to be air-tigh
Testing Equipment, Tools and Materials
General Information
Note
This list outlines the testers, tools and materials required
for expert refrigerant circuit repair work.
For tools and materi
SEE MORE:
Preparation
You should only perform the steps that follow if
you have the necessary tools and technical expertise.
If the engine does not start because the vehicle
battery is drained, you can jump start your vehicle
using another vehicle. Jump start cables are
needed to do this.
Both vehicle batter
Note
Depending on vehicle equipment, there are different versions
of the A/C system for the Audi Q7. Make sure to use the correct
version and pay attention to the allocation of different
components. Refer to
→ Chapter "A/C System Versions" and Parts Catalog.
For this vehicle, t