Checking heating output of air conditioner — AUDI

Audi
Audi Q7
2007
Heating, ventilation, air conditioning system
Heating, air conditioning
Edition
04.2013
Checking heating output of air conditioner
Check operation of the
coolant circulation pump
V50
, the
coolant pump
V36
, the
coolant shut-off valve
N82
and the
supplementary air heater element
Z35
.
Note
As of Model Year 2009 and depending on the applicable emissions standard, certain vehicles with 6-cyl. TDI engine and no
“auxiliary heater”
optional extra are fitted with a
supplementary air heater element
Z35
instead of a fuel-driven supplementary heater (gradual introduction with the corresponding engine)
Chapter
,
Audi Sales Range
and
Auxiliary/supplementary heater
Rep. gr.
82
.
Vehicles with diesel engine and no fuel-driven supplementary heater (or
“auxiliary heater”
as optional extra) are fitted in the area of the heat exchanger with a
auxiliary air heater element
Z35
. The
auxiliary air heater element
Z35
additionally warms the air after leaving the heat exchanger in the front air conditioning unit.
Removing and installing
auxiliary air heater element
Z35
Chapter
; checking
Chapter
If the coolant circuit is not completely bled after filling, air may accumulate in the heat exchangers of the air conditioning unit(s) and thus reduce the heat output of the air conditioner. In addition, noise may occur or complaints may be received about differences in the temperature of the air from the driver's and front passenger's vents despite identical setting. Bleed the coolant circuit if necessary
Chapter
.
Depending on the engine, the coolant circulation for the air conditioner is provided by different pumps, or the engine coolant pump is assisted by these pumps with the engine running. Vehicles with 8-cyl. engine, 6-cyl. TDI engine and 12-cyl. TDI engine are fitted with the
coolant circulation pump
V50
. Vehicles with 6-cyl. petrol engine feature the
coolant pump
V36
. Vehicles with 6-cyl. petrol engine and auxiliary heater as optional extra are fitted with both the
coolant pump
V36
and the
coolant circulation pump
V50
Chapter
and
Auxiliary/supplementary heater
Rep. gr.
82
In the event of customer complaints about poor heat output at certain engine speeds, check the incorporation of the air conditioner into the coolant circuit. If the two coolant hoses (supply and return) from the engine to the heat exchanger via the
coolant circulation pump
V50
(
coolant pump
V36
) have been interchanged, the engine coolant pump works in opposition to the
coolant circulation pump
V50
(
coolant pump
V36
) and at certain engine speeds coolant no longer flows into the heat exchanger(s)
Chapter
,
Auxiliary/supplementary heater
Rep. gr.
82
and
Engine, mechanics
Rep. gr.
19
Vehicles with diesel engine and no fuel-driven supplementary heater / no
“auxiliary heater”
as optional extra are fitted in the area of the heat exchanger with an
auxiliary air heater element
Z35
Chapter
. The
auxiliary air heater element
Z35
additionally warms the air after leaving the heat exchanger. Check actuation and operation of the
auxiliary air heater element
Z35
Chapter
and
"Guided Fault Finding" function of vehicle diagnostic, testing and information system VAS 5051.
From model year 2011 onwards, a start/stop system (optional equipment) is offered for this vehicle in combination with certain engines. In the event of problems with poor heat output with the stop function active on these vehicles, pay attention to the correct version, encoding and adaption of the front operating and display unit,
Climatronic control unit
J255
Electronic parts catalogue
and
"Guided Fault Finding" function of vehicle diagnostic, testing and information system VAS 5051
.
On vehicles with a start/stop system, the
coolant circulation pump
V50
is activated during the stop function by
J255
if heat output is required to heat the passenger compartment. If problems with poor heat output are encountered on such vehicles when the stop function is active, check operation of
V50
"Guided Fault Finding" function of vehicle diagnostic, testing and information system VAS 5051
.
In the event of problems with poor heat output with the stop function active on vehicles with a start/stop system and auxiliary/supplementary heater, additionally pay attention to the correct version, encoding and adaption of the auxiliary/supplementary heater (
supplementary heater control unit
J364
)
Electronic parts catalogue
and
"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051
.
Vehicles as of Model Year 2011 with a diesel engine and a start/stop system, but with no
“auxiliary heater”
as optional extra (with fuel-driven supplementary heater or
supplementary air heater element
Z35
) may additionally be fitted with a
heater coolant shut-off valve
N279
. In the event of problems with lack of heat output on such vehicles, additionally check actuation and operation of
N279
(fitting location
Auxiliary/supplementary heater
Rep. gr.
82
, incorporation into vehicle electrical system and actuation of
N279
Current flow diagrams, Electrical fault finding and Fitting locations
). On vehicles with
Z35
,
N279
is actuated via a relay (e.g. the
coolant shut-off valve relay
J541
) by the front operating and display unit,
Climatronic control unit
J255
Current flow diagrams, Electrical fault finding and Fitting locations
and
"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051
As of Model Year 2014, vehicles with certain engines with no
“auxiliary heater”
as optional extra will be fitted with a
coolant shut-off valve
N82
.
N82
is actuated by the front operating and display unit,
Climatronic control unit
J255
(via the
coolant shut-off valve relay
J541
) if passenger compartment heating is not required
Chapter
and
Current flow diagrams, Electrical fault finding and Fitting locations
. In the event of problems with lack of heat output on such vehicles, additionally check actuation and operation of
N82
"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051
.
Special tools and workshop equipment required
Vehicle diagnostic, testing and information system
VAS 5051 A
(or
Service Information System
VAS 5052
)
"Guided Fault Finding" function of vehicle diagnostic, testing and information system VAS 5051
Battery charger, 60A
VAS 5904
Commercially available thermometer (for temperature measurement; if applicable use thermometer with 2 probes for simultaneous measurement of temperature e.g. on right and left)
Note
On vehicles with an air conditioner of
“deluxe”
type, the given temperatures can either be measured directly or read out by way of the
“Reading measured value block”
function
"Guided Fault Finding" function of vehicle diagnostic, testing and information system VAS 5051.
On vehicles with an air conditioner of
“Basic”
type, the given temperatures have to be measured manually, there are no suitable temperature sensors fitted
"Guided Fault Finding" function of vehicle diagnostic, testing and information system VAS 5051.
Chapter
“
Checking operation of
coolant circulation pump
V50
(
coolant pump
V36
)
”