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– If customer complains of poor heating performance at specific
engine speeds, check incorporation of heater core in A/C sys‐
tem in the coolant circuit. If both coolant hoses (supply and
return) of engine are interchanged, coolant is flowing in the
wrong direction through the heater core. Refer to⇒ Engine
Mechanical; Rep. Gr. 19 ; Description and Operation .
♦ Requirements for performing the heat output test, refer to
⇒ “4.6.2 Heat Output Test Requirements“, page 94
♦ Heating performance, checking
⇒ “4.6.3 Heating Performance, Checking“, page 94
4.6.2
Heat Output Test Requirements
♦ Coolant circuit has been bled according to specifications. Re‐
fer to⇒ Engine Mechanical; Rep. Gr. 19 ; General Informa‐
tion .
♦ All air ducts, covers and seals OK and properly installed
♦ Air flow through dust and pollen filter not obstructed by dirt.
♦ Engine is warm
♦ Climatronic control module -J255- DTC memory was checked
and erased, basic setting was performed and Climatronic con‐
trol module coding was checked. Refer to Vehicle diagnosis,
testing and information system -VAS5051B- under "Guided
Fault Finding".
♦ The Climatronic control module was checked. Refer to Vehicle
diagnosis, testing and information system -VAS5051B- under
"Guided Fault Finding".
♦ Vehicle not exposed to sunlight.
4.6.3
Heating Performance, Checking
The heat output test requirements are met. Refer to
⇒ “4.6.2 Heat Output Test Requirements“, page 94
.
– Close hood.
– Close doors, windows and rear lid.
– Open all dash panel vents.
– Perform OBD on the A/C system. Refer to Vehicle diagnosis,
testing and information system -VAS5051B- under "Guided
Fault Finding".
– Start engine and let it run a few minutes with maximum cooling
output (A/C compressor is switched on, indicator light on
AC
button lights up).
– In “read measured values block“ read the display for the A/C
compressor regulator valve -N280- actuation and refrigerant
circuit pressure. Refer to Vehicle diagnosis, testing and infor‐
mation system -VAS5051B- under "Guided Fault Finding" (the
A/C compressor will be actuated and the refrigerant circuit
pressure is OK. Refer to
⇒ “4.2.2 Cooling Output, Checking“, page 81
– Turn the Climatronic control module -J255- temperature rotary
switch to “cold“.
– Adjust air output direction via the air distribution rotary switch
on the Climatronic control module to “footwell“.
– Read the measured values from the left footwell vent temper‐
ature sensor -G261- , from the right footwell vent temperature
sensor -G262- and from the evaporator vent temperature sen‐
sor -G263- . Refer to Vehicle diagnosis, testing and informa‐
tion system -VAS5051B- under "Guided Fault Finding".
Audi TT 2007 ➤
Heating, Ventilation and Air Conditioning - Edition 01.2011
94
Rep. Gr.87 - Air Conditioning
