Audi Q7 2007 Repair Manual page 69

Note
Depending on the composition of the windshield washer fluid,
♦
the Air Quality Sensor - G238- can determine impurities in the
air and request for "automatic air recirculation".
If no changeover to recirculating air mode occurs when oper‐
♦
ating switch for windshield wiper/washer system, check func‐
tion (the information "Wash Windshield" is received via
Comfort CAN-Bus system). Use the Vehicle Diagnostic Tester
via the "Guided Fault Finding" function.
If the Air Quality Sensor - G238- functionality is OK for this test
and there is a customer complaint, continue as follows:
– Check dust and pollen filter for dirt. Refer to
⇒ "9.35 Dust and Pollen Filter, Removing and Installing", page
169 .
– Connect the scan tool and select the "read measuring values
block". Use the Vehicle Diagnostic Tester via the "Guided
Fault Finding" function.
– Since the displayed values are read out while vehicle is driven,
a second mechanic is required (observe safety precautions
found here. Use the Vehicle Diagnostic Tester via the "Guided
Fault Finding" function).
– Select the display group with the measured values for the Air
Quality Sensor - G238- and for the recirculating/fresh air door
position. Use the Vehicle Diagnostic Tester via the "Guided
Fault Finding" function.
– Start by driving vehicle into an area with a relatively clean at‐
mosphere (A/C system is working in fresh-air mode).
– Then drive vehicle into an area where the atmosphere is pol‐
luted (for example, onto an uphill road with truck traffic).
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– Read the display with the measured value for the Air Quality
with respect to the correctness of information in this document. Copyright by AUDI AG.
Sensor - G238- and for the recirculating/fresh air door position.
The display must change, for example when driving through a
diesel gas cloud (for example, from fresh air mode to "Auto‐
matic Air Recirculation"). Use the Vehicle Diagnostic Tester
via the "Guided Fault Finding" function.
– Also note descriptions of the dust and pollen filter (refer to
⇒ "9.36 Dust and Pollen Filter with Activated Charcoal Filter
Unit", page 170 ) and Air Quality Sensor - G238- function.
Refer to
⇒ "5.5 Air Quality Sensor G238 Functionality", page 58
Heating, Ventilation and Air Conditioning - Edition 04.2013
5. A/C System Control and Regulation Components Outside Passenger Compartment
.
Audi Q7 2007 ➤
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