Audi Q7 2007 Repair Manual page 38

Audi Q7 2007 ➤
Heating, Ventilation and Air Conditioning - Edition 04.2013
Note
This illustration shows the connector -B- on an A/C compres‐
♦
sor on a 6-cylinder engine. For the correct allocation for vehi‐
cles with a different engine, refer to
⇒ "16.4 Compressor, Removing and Installing (Vehicles with
8-Cylinder FSI Engine)", page 283
inder FSI or 8-Cylinder TDI, Removing and Installing) or
⇒ "16.3 Compressor, Removing and Installing (Vehicles with
12-Cylinder TDI Engine)", page 280
Cylinder TDI, Removing and Installing)
The A/C Compressor Regulator Valve - N280- activation and
♦
the current flowing through the A/C Compressor Regulator
Valve - N280- measured by the Climatronic Control Module -
N280- front A/C control head is displayed in the Climatronic
Control Module - J255- front A/C control head measured val‐
ues block. Use the Vehicle Diagnostic Tester via the "Guided
Fault Finding" function.
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 valve -N280- . Refer to ⇒ Refrigerant
R134a Servicing; Rep. Gr. 87 ; A/C System General Informa‐
tion (Refrigerant R134a, Servicing; Refrigerant Circuit Com‐
ponents, Replacing).
The A/C compressor regulator valve -N280- is not available as
♦
a replacement part for all A/C compressors. If the A/C com‐
pressor regulator valve -N280- is not available as an individual
A/C compressor part (different versions), then the entire A/C
compressor must be replaced. Refer to the Parts Catalog.
If connectors to the A/C Compressor Regulator Valve - N280-
♦
and to electric engine mount are interchanged, no DTC is
entered in DTC memory (the electrical values of these com‐
ponents are about the same), however the evaporator may
ice-up since the compressor is actuated continuously.
An adapter cable can also be used for this test. To do this, for
♦
example, use one connector each -A- and -B- (part number
1J0 973 702 and 1J0 973 802 and relevant terminal contacts),
two standard sockets for banana connectors -C- and two wires
2
with 0.5 mm diameter.
– Connect DSO Measuring Leads 1 and 2 - VAS5051/8- to
adapter leads.
– Measuring lead (signal wire) to wire to connector terminal
-2-.
– Measuring lead (shielding, Ground) to wire to connector ter‐
minal -1-.
– Set the operating mode Test Instruments: DSO (Digital Stor‐
age Oscilloscope) on the Vehicle Diagnostic Tester.
– Setting 5V/Div = 0.5 ms/Div (5 volts DC and 0.5 milliseconds
per unit)
– Start engine.
– Set temperature preselect on the Climatronic Control Module
- J255- front A/C control head to "Cold" (for example, temper‐
ature preselect "Lo" for driver's and front passenger's side).
32
Rep. Gr.87 - Air Conditioning
(A/C Compressor, 8-Cyl‐
(A/C Compressor, 12-
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