A/C System Temperature Door Heat Output Activation, Checking
Special tools and workshop equipment required
- Battery Charger VAS5903
- Vehicle Diagnostic Tester.
- A standard thermometer (for temperature measurements, if necessary a thermometer with two measuring probes for simultaneous measurement, for example, for temperature on the right and left)
On vehicles with a high voltage system (hybrid vehicles)
Observe all of the additional warnings for all work performed on vehicles with the high voltage system. Refer to HIGH VOLTAGE VEHICLES SAFETY PRECAUTIONS and HIGH VOLTAGE SYSTEM GENERAL WARNINGS .
If it is necessary for the following procedure to perform work near high voltage components, "perform a visual inspection of the high voltage components and cables for damages" (refer to PERFORMING A VISUAL INSPECTION OF DAMAGE TO HIGH VOLTAGE COMPONENTS AND CABLES ) and "always follow the warnings when working on the high voltage system". Refer to HIGH VOLTAGE SYSTEM GENERAL WARNINGS .
Risk of unintended engine start
The ignition must be turned off and the ignition key must remain outside of the vehicle when working on vehicles with a high voltage system.
Handling high voltage cables:
- Do not stand on or place tools on high voltage cables and their components as it may damage the cable insulation.
- Never bend or kink high voltage cables forcefully as it may damage the cable insulation.
- The round high voltage connectors are color coded with an external color ring and are mechanically coded using the guide- or code tabs. Always make certain that the coding matches when connecting the round connector in order to avoid any mechanical damage the high voltage connector.
There is a risk of electrocution from damaged high voltage components.
Observe the following when working around high voltage components and high voltage wires:
- Never work around high voltage components and cables with cutting, deformed, or sharp edged tools, or heat sources such as welding or soldering tools, heated air, and thermal glue.
- Inspect the high voltage components visually before beginning.
- Perform a visual inspection of the Electric Drive Power and Control Electronics -JX1-, the Electro-Drive Drive Motor -V141-, the Electrical A/C Compressor -V470- and the high voltage lines when working in the engine compartment.
- Perform a visual inspection of the high voltage lines and covers when working on the underbody.
- Perform a visual inspection of the high voltage lines and the Electrobox with the High Voltage System Maintenance Connector -TW- when working in the luggage compartment.
- Perform a visual inspection on all of the potential equalization cables.
Observe the following items when performing the visual inspection:
- The components do not display any signs of external damage.
- The high voltage cable insulation and the potential equalization cables are not damaged.
- The high voltage cables do not display any abnormal deformations.
- Every high voltage component is marked with a red warning label.
Working on a high voltage system when activated or with the ignition turned on
The engine may start unexpectedly when performing work while the ignition is turned on or when the ready mode is activated and may cause poisoning in enclosed spaces. Be aware of body limbs and/or clothing when clamping or pulling.
Perform the following steps before turning on the ignition:
- Move the selector lever into position P.
- Activate the parking brake.
- Switch off ignition.
- Open the engine hood.
- Connect the charging unit for example Battery Charger VAS5903 to the battery jump start terminal for the 12V vehicle electrical system
- Switch on the ignition.
-- Charge the vehicle battery, for example, using the Battery Charger VAS5903 in the battery support mode to minimize the number of automatic starts during the test- and measuring procedures when the ready mode is active. Refer to Battery Charger VAS5900 SUPPORT MODE and HIGH VOLTAGE SYSTEM GENERAL WARNINGS .
-- Move the selector level into position "P", activate the parking brake and arrange the necessary tools for testing and measuring procedures that require the ready mode to be active or that require the ignition to be on, so that they cannot come into contact with the turning components in the engine and so that they are not in the vicinity of the turning components of a running engine.
Also move the selector lever into position "P" and activate the parking brake for testing and measuring procedures which require the ignition to be on, but do not require the ready mode to be active.
The ready mode is displayed in the Instrument Cluster Control Module -J285- above the "power meter". Refer to Owner's Manual.
Activate and deactivate the ready mode. Refer to Owner's Manual (consult the display in the Instrument Cluster Control Module -J285-).
The engine may start unexpectedly when performing work while the ignition is turned on or when the ready mode is activated and may cause poisoning in enclosed spaces. Be aware of body limbs and/or clothing when clamping or pulling.
Perform the following steps before turning on the ignition:
- Move the selector lever into position P.
- Activate the parking brake.
- Switch off ignition.
- Open the engine hood.
- Connect the charging unit for example Battery Charger VAS5903 to the battery jump start terminal for the 12V vehicle electrical system
- Switch on the ignition.
If the ignition is turned on and the ready mode is active, the engine runs or starts only, when heated coolant is necessary to reach the temperature setting in the passenger compartment or, for example, the Traction Battery -A2- (hybrid battery) has not been charged enough.
The coolant flow through is maintained by the heater core for the A/C system via the Coolant Recirculation Pump -V50- when the ignition is turned on and the drive ready mode is active (the engine is not running). Refer to COMPONENT GROUP "3" . Also, refer to the appropriate CONNECTION DIAGRAM - COOLANT HOSES -item 5- for CALB, CONNECTION DIAGRAM - COOLANT HOSES -item 10- for CPNB, CONNECTION DIAGRAM - COOLANT HOSES -item 11- for CTUC and CTUD, COOLANT HOSE, CONNECTION DIAGRAM, NON-HYBRID VEHICLES WITH ALL ENGINE CODES EXCEPT CDZA -item 7- for CAEB, CPMB, CPMA, or CONNECTION DIAGRAM, COOLANT HOSE, HYBRID VEHICLES -item 3- for CHJA, . Depending on the vehicle version, the Coolant Recirculation Pump -V50- is activated directly by the Climatronic Control Module -J255- A/C display and control head or at the request of the Climatronic Control Module -J255- from the respective engine control module. Refer to appropriate SYSTEM WIRING DIAGRAM.
-- Activate the ready mode (observe the display in the Instrument Cluster Control Module -J285-). Refer to Owner's Manual.
All vehicles
If coolant circuit is not completely bled after filling, air may accumulate in heater core of A/C unit, thus reducing heating output of A/C system, additional noises may occur or customer may complain of different air temperatures flowing out of vents at driver side and front passenger's side at the same setting.
Corrective measure:
-- Perform a longer road test at a higher engine RPM with the setting "A/C system maximum heating output" (at least for 10 minutes, engine RPM higher than 2, 500). Select a low gear during the test to prevent excessive vehicle speed.
-- If the customer complains of poor heating output at certain engine speeds, check the incorporation of the A/C heater core in the coolant circuit. If both coolant hoses (supply and return) of the engine are interchanged, the coolant flows through the heater core in the wrong direction. Refer to CONNECTION DIAGRAM - COOLANT HOSES for CALB, CONNECTION DIAGRAM - COOLANT HOSES for CPNB, CONNECTION DIAGRAM - COOLANT HOSES for CTUC and CTUD, COOLANT HOSE, CONNECTION DIAGRAM, NON-HYBRID VEHICLES WITH ALL ENGINE CODES EXCEPT CDZA for CAEB, CPMB, CPMA, or CONNECTION DIAGRAM, COOLANT HOSE, HYBRID VEHICLES for CHJA, .
If a different air temperature is coming out of the vents during A/C system control mode, it may be caused by the following.
- One or more of the temperature flaps in the radiator housing do not close completely or do not reach their end position.
- There is air in the heat exchanger (fluctuating flow through heat exchanger and heat is not distributed uniformly).
- A foam seal has loosened during installation of heater core and air may flow past at heater core. Refer to HEATER CORE, REMOVING AND INSTALLING .
- If, when installing the Auxiliary Heater Heating Element -Z35- /honeycomb, a foam seal has become loose, air can flow out where the seal has separated. Refer to Auxiliary Heater Heating Element -Z35-, REMOVING AND INSTALLING .
- The A/C system refrigerant circuit is not filled with the correct quantity of refrigerant (perform a cooling output test). Refer to COOLING OUTPUT, CHECKING .
From MY 2010, this vehicle has a Start/Stop System for specific engines as optional equipment. The setting on the Climatronic Control Module -J255- A/C display and control head can prevent the stop function. If, for example, "defrost" is selected, the stop function is not possible or will be interrupted and the engine will start. The same applies in the case of heating and cooling. The difference between the selected and actual temperature exceeds a certain value using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
For vehicles with the Start/Stop System, an additional Coolant Recirculation Pump -V50- (Water Pump -V36-) is installed for the Start/Stop System, depending on the vehicle equipment level and vehicle version. Refer to COMPONENT GROUP "3" . Also, refer to the appropriate CONNECTION DIAGRAM - COOLANT HOSES -item 5- for CALB, CONNECTION DIAGRAM - COOLANT HOSES -item 10- for CPNB, CONNECTION DIAGRAM - COOLANT HOSES -item 11- for CTUC and CTUD, COOLANT HOSE, CONNECTION DIAGRAM, NON-HYBRID VEHICLES WITH ALL ENGINE CODES EXCEPT CDZA -item 7- for CAEB, CPMB, CPMA, or CONNECTION DIAGRAM, COOLANT HOSE, HYBRID VEHICLES -item 3- for CHJA, and using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
Depending on the vehicle version, the Coolant Recirculation Pump -V50- (Water Pump -V36-) is activated not only when the "Stop function" is active, but also when the engine is running (when, for example, the "warm" temperature preset is selected on the Climatronic Control Module -J255- A/C display and control head ("HI" in the display on the A/C display and control head and the display in the MMI). The Coolant Recirculation Pump -V50- (Water Pump -V36- is activated to support the engine coolant pump using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
The Coolant Recirculation Pump -V50- (Water Pump -V36-) version and activation differ depending on the vehicle version and production period. From MY 2012 as a running change, the pumps installed from the start of production, which were activated via a 500 Hertz signal (500 pulses per second), are being replaced by pumps that are activated by a variable (100 to 500 Hertz) signal depending on the engine. Pumps that are activated by a variable signal are also equipped with a diagnostic function and are activated mostly via the respective engine control module. Therefore, ensure the correct allocation (only the allocated pump can be activated) using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function, refer to appropriate SYSTEM WIRING DIAGRAM .
The actuation of the temperature doors differs between the "Basis" A/C system and the "Convenience" A/C system. Refer to TEMPERATURE DOORS IN THE LEFT AND RIGHT RADIATOR HOUSING .
-- On the "Convenience" A/C system, the right front temperature door is actuated by the Right Temperature Door Motor -V159- and left front temperature door by the Left Temperature Door Motor -V158-. Both temperature doors for the rear right footwell vents and the rear left footwell vent, as well as the vent in the rear center console are connected by a connecting rod; they are actuated by the Rear Temperature Door Motor -V137-
-- On the "Basis" A/C system, the upper and lower temperature doors (for the front right vents and the right footwell vents) as well as the upper and lower temperature doors (for the front left vents and the left footwell vents) are connected to each other by the shafts. The right and left temperature door shafts are connected to each other by a connecting rod; they are both actuated by the Temperature Regulator Door Motor -V68-.
Information for vehicles with a parking heater
If there are complaints that there is poor or insufficient heating output on a vehicle with a "parking heater", then check the activation and function of the Heater Coolant Shut-Off Valve -N279- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function (parking heater).
- On the Audi Q5, the Heater Coolant Shut-Off Valve -N279- can be actuated only up to an engine RPM of approximately 1, 200. If the Heater Coolant Shut-Off Valve -N279- is actuated at a higher engine RPM, it may not open when the activation is switched off due to the increased flow of coolant (and not warmed up coolant is flowing into the A/C heater core).
If, for vehicles with an optional "parking heater", there are complaints that there is poor or insufficient heating output at lower engine RPMs, check the activation and function of the Recirculation Pump -V55- for the parking heater (the request is made by the Climatronic Control Module -J255- A/C display and control head, the activation is carried out by the Auxiliary Heater Control Module -J364-).
- The Climatronic Control Module -J255- sends the request to activate the Recirculation Pump -V55- so that it can support the engine coolant pump at specific engine RPMs, depending on the version of the vehicle, of the engine, of the parking heater and when the vehicle was manufactured. This function must be properly adapted in the Auxiliary Heater Control Module -J364- so that the request to activate the Recirculation Pump -V55- by the Auxiliary Heater Control Module -J364- can be performed.