HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION

Special Tools And Workshop Equipment Required

Battery Charger :VAS5904
Battery Charger :VAS5095A

NOTE:

For vehicles with a high-voltage system (Audi A6 Hybrid), there is currently no "Basic" A/C system version offered.

Vehicles with High-Voltage System (Audi A6 e-tron)

Read and follow all of the supplemental warnings for all work performed on vehicles with the high-voltage system. Refer to HIGH VOLTAGE VEHICLES SAFETY PRECAUTIONS .

If it is necessary for the following procedure to perform work in the vicinity of high-voltage components, "perform a visual inspection of the high-voltage components and cables for damages" (Refer to HIGH VOLTAGE VEHICLES SAFETY PRECAUTIONS .) and "always follow the warnings when working on the high-voltage system" .

WARNING:

Risk of engine starting unexpectedly

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.

WARNING:

Working With 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 to the high-voltage connector.

CAUTION:

There is a risk of electrocution from damaged high-voltage components.

Observe The Following When Working Around High-Voltage Components And High-Voltage Cables:

Never work around high-voltage components and cables with cutting, deformed, sharp edged tools, or heat sources such as welding or soldering tools, heated air, and thermal glue.
Perform a visual inspection of the work area before working on the high-voltage components.
Perform a visual inspection of the Electric Drive Power and Control Electronics -JX1-, the Electric Drive Drive Motor -V141-, the Electrical A/C Compressor -V470- and the high-voltage cables when working in the engine compartment.
Perform a visual inspection of the high-voltage cables and covers when working on the underbody.
Perform a visual inspection of the high-voltage cables and the hybrid battery unit 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.

Pay Attention To The Following Items When Performing A Visual Inspection:

Components must not show any signs of external damage.
The high-voltage cable insulation and the potential equalization cables must not be damaged.
The high-voltage cables must not display any abnormal deformations.
Every high-voltage component must be marked with a red warning label.

Working on a high-voltage system when activated or with the ignition turned on

CAUTION:

The engine may start unexpectedly and may cause a toxicity hazard in confined spaces when performing work while the ignition is turned on or when the ready mode is activated. Risk of pinching or pulling parts of the body and clothing.

Perform The Following Steps Before Switching On The Ignition:

Move the selector lever into P position.
Activate the parking brake.
Turn off the ignition.
Open the engine hood.
Connect the charging unit, for example the :VAS5095A , to the battery jump start terminal for the 12V vehicle electrical system
Switch on the ignition.

-- Charge the vehicle battery, for example, using the :VAS5904 in the battery support mode to minimize the number of automatic starts during the test- and measuring procedures while the ready mode is active. Refer to BATTERY, CHARGING and HIGH VOLTAGE VEHICLES SAFETY PRECAUTIONS .

-- For testing and measurement procedures that require the ready mode to be active or the ignition to be switched on, the selector lever must be in the "P" position and the parking brake must be activated. The required tools must be placed so that they do not come into contact with any rotating components in the engine and they must also not go into the vicinity of the rotating components when the engine is running.

NOTE:

Also move the selector lever into the "P" position and activate the parking brake for testing and measurement 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 appropriate service/repair/system information.

For activating and deactivating the ready mode, refer to the appropriate service/repair/system information (while doing so, note the display in the Instrument Cluster Control Module -J285-).

-- Activate the ready mode (observe the display in the Instrument Cluster Control Module -J285-). Refer to appropriate service/repair/system information.

All Vehicles

The test requirements are met. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, TESTING REQUIREMENTS .

-- Close the engine hood.

-- Close the doors, the engine hood, the windows, the sliding sunroof and the rear lid.

-- Open all instrument panel vents and the vents in the rear center console.

-- Turn on the ignition and prepare the ready mode, the engine starts automatically as needed (on vehicles with a Start/Stop System and on Audi A6 e-tron).

-- Start the engine (not for the Audi A6 e-tron).

NOTE:

The Rear Temperature Selection Potentiometer -G538- is installed in the rear center console only for certain market specific vehicles.

The rear vent temperature control doors are activated (by the Rear Temperature Control Door Motor -V137-) via a characteristic curve stored in the Climatronic Control Module -J255- control head. If the setting between the left and right side in the Climatronic Control Module -J255- and/or the setting on the Rear Temperature Selection Potentiometer -G538- greatly differs, then the temperature doors for the rear vents are no longer set in the end stops. The activation of the temperature doors for the temperature of the air coming out of the rear vents depends on the setting on the Rear Temperature Selection Potentiometer -G538-, which has a tendency to be somewhat warmer or cooler than the air for the front vents.

The following is set on the Climatronic Control Module -J255- control head:

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"Auto" operating mode - the indicator lamp in the AUTO button -1- illuminates.
Temperature preset "Cold" - both dials -2 and 5- set at stop "cold".
A/C compressor turned on - The indicator lamp in the AC -button -6- illuminates.
Preset for the fresh air blower -4- "maximum speed".
Set the air flow direction via the buttons -7- to "footwell" and "instrument panel vent".
The Rear Temperature Selection Potentiometer -G538- -1- is all the way on "cold", if applicable.

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NOTE:

The indicator lamp in the AUTO button goes out when manually changing the airflow direction and/or the fresh air blower speed.

The maximum possible fresh air blower speed depends on various ambient influences (electrical system voltage, etc.)

The instrument panel vent and the rear center console vents are open.

-- Select the function "read measured value" from the A/C system on the Climatronic control module -J255- using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

-- Let the A/C system run for several minutes at the maximum cooling output.

The A/C compressor is turned on - the indicator lamp illuminates in the AC -button.

-- Compare the measured value of the Evaporator Vent Temperature Sensor -G263- with the measured values of the Left Vent Temperature Sensor -G150- Right Vent Temperature Sensor -G151-, Left Footwell Vent Temperature Sensor -G261- and Right Footwell Vent Temperature Sensor -G262-.

Specified Values

Target value: Measured temperature sensor (according to the heater core) Left Vent Temperature Sensor -G150-, Right Vent Temperature Sensor -G151-, Left Footwell Vent Temperature Sensor -G261-, Right Footwell Vent Temperature Sensor -G262- and the measured air temperature from the vents in the rear center console may be a maximum of 9 °C (48.2 °F) greater than the value for the Evaporator Vent Temperature Sensor -G263- after five minutes.

NOTE:

Due to the design of the A/C unit and the air routing in the vehicle, a certain increase in air temperature always occurs on the way from the evaporator to the vents.

-- If the required values for the front temperature sensor are not reached, perform a fault finding at the temperature increase after the evaporator. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION .

NOTE:

If the measured value at one or two temperature sensors deviates from the measured values of the other temperature sensors, check this temperature sensor and the actuator which activates the temperature control door that is upstream from this temperature sensor. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

-- If the required values for the air flowing through the rear center console vents are not reached, determine the cause of the malfunction. Refer to DETERMINING MALFUNCTION IF COOLING OUTPUT OF FRONT A/C SYSTEM IS OK BUT REQUIRED VALUES ARE NOT ACHIEVED IN "Basic" VERSION .

The following is set on the Climatronic Control Module -J255- control head:

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Temperature preset "warm" - both dials -2 and 5- are set at stop "warm".

The Rear Temperature Selection Potentiometer -G538- -1- is all the way on "warm", if applicable.

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-- Read the displayed measured values for the various temperature sensors: Left Vent Temperature Sensor -G150-, Right Vent Temperature Sensor -G151-, Left Footwell Vent Temperature Sensor -G261- and Right Footwell Vent Temperature Sensor -G262-.

Specified Values

The measured temperature for all temperature sensors increases to above 50 °C (122 °F) (depending on the engine temperature at the time).

NOTE:

For vehicles without the Coolant Recirculation Pump -V50- / Recirculation Pump -V55-, the motor speed must be accelerated as necessary and marginally to at least 1400/min in order to reach the necessary refrigerant flow through the heater core for the heater in the air distribution housing.

The required values are achieved at all temperature sensors:

Continuation of the test - Separation for the temperature control between the left and right side in the A/C unit. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION .

If the required values are not reached on any of the temperature sensors (and also not at a higher speed):

If equipped, check the activation and function of the Coolant Recirculation Pump -V50- and the Coolant Shut-Off Valve -N82- (the Thermal Management Coolant Pump 2 -V618- on the Audi A6 e-tron). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
On vehicles with a parking heater, check the activation and the function of the Recirculation Pump -V55- and the Heater Coolant Shut-Off Valve -N279-. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
Check the incorporation of the A/C system into the coolant circuit. Refer to COMPONENT LOCATION OVERVIEW - ENGINE COOLANT CIRCUIT .
Check the coolant circuit bleeding .
Check the heating output of the A/C system at an engine speed of 1500 to 2000 RPM (repeat the test at a higher engine speed). If the required heating output is reached at this engine speed, the fault is not in the A/C unit but rather in the coolant circuit (incorporation of the A/C system into the coolant circuit, engine coolant pump delivery rate, the coolant flowing through the heater core in the A/C unit, incorporation of the Coolant Recirculation Pump -V50- / Coolant Shut-Off Valve -N82- or Recirculation Pump -V55- / Heater Coolant Shut-Off Valve -N279- into the coolant circuit, etc.). Refer to COMPONENT LOCATION OVERVIEW - ENGINE COOLANT CIRCUIT .
Check the thermostat for the coolant temperature in the engine (the engine coolant may not heat properly if the thermostat is malfunctioning) .
Check the engine coolant pump for proper function (if the coolant pump is faulty or a Coolant Recirculation Pump -V50- / Recirculation Pump -V55- or the Thermal Management Coolant Pump 2 -V618- on the Audi A6 e-tron is incorrectly integrated, there may be too little coolant flowing through the heater core for the heater in the air distribution housing) .

If the required values are not reached at only one or two temperature sensors:

Check the coolant circuit bleeding .
Check the activation and function of the various actuators for the temperature control doors in the A/C unit. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
Check the measured values of the various temperature sensors. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
In the event that the determined temperatures are too high at the "cold" setting, perform a Guided Fault Finding if there is a temperature increase after to the evaporator. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION .
In the event that the determined temperatures are too low on the "warm" setting or that there is too big of a difference between the right and left, check the foam seal on the air distribution housing heater core for the heater. Refer to HEATER CORE, REMOVING AND INSTALLING .
In vehicles with an Auxiliary Heater Heating Element -Z35-, check the separation between the left and right side in the air distribution housing via the installation shaft for the auxiliary heater heating element -Z35-. Refer to Auxiliary Heater Heating Element -Z35-, REMOVING AND INSTALLING .

Continuation Of The Heating Output Test For A/C Units - Checking The Separation For The Temperature Control Between The Left And Right Side In The A/C Unit.

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-- Set the temperature setting for the passenger side (front and rear) to "cold" via the dial -5- on the Climatronic Control Module -J255- control head.

-- The temperature setting for the driver side (front and rear) remains on "warm".

-- Select the function "read measured value" from the A/C system on the Climatronic Control Module -J255- using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.

-- Let the A/C system run for several minutes at this setting.

The A/C compressor is turned on and the indicator lamp illuminates in the AC -button -6-.

-- Compare the measured value of the Evaporator Vent Temperature Sensor -G263- with the measured values of the Left Vent Temperature Sensor -G150-, Right Vent Temperature Sensor -G151-, Left Footwell Vent Temperature Sensor -G261- and Right Footwell Vent Temperature Sensor -G262-.

NOTE:

At the temperature setting "warm" for one side (the driver or front passenger side), the target outflow temperature at the evaporator is regulated to a higher value (up to approximately 10 °C (50 °F)) by the control head, the Climatronic Control Module -J255-.

The temperature of the air flowing from the rear vents is regulated by the Climatronic Control Module -J255- control head.

Specified Values

On the Left Vent Temperature Sensor -G150- and Left Footwell Vent Temperature Sensor -G261-, the temperature remains above 45 °C (113 °F) (depending on the current engine temperature).
On the Right Vent Temperature Sensor -G151- and Right Footwell Vent Temperature Sensor -G262-, the temperature drops to a value which may be a maximum of 15 °C (59 °F) higher than the measured value of the Evaporator Vent Temperature Sensor -G263- within 5 minutes.
When setting one side to "warm" and for the other side to "cold" on the control head, the air from the vent in the rear center console is no longer regulated and is maximally heated.
The temperatures of the temperature sensors on one side (Left Vent Temperature Sensor -G150- and Left Footwell Vent Temperature Sensor -G261-) and (-G151- and Right Footwell Vent Temperature Sensor -G262-) displayed in the "read measured values" function equalize within five minutes (the particular temperature difference is less than 9 °C (48.2 °F)).

If the target values are reached, the test is finished for vehicles without a Rear Temperature Selection Potentiometer -G538-.

Vehicles With Rear Temperature Selection Potentiometer -G538- :

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-- Set the temperature for the right side on the Climatronic control module -J255- to "warm" wait several minutes.

-- Measure the temperature of the air flowing from the rear center console vent.

-- Set the thumbwheel -1- to "cold" at the Rear Temperature Selection Potentiometer -G538-.

The temperature of the air flowing from the rear center console vent decreases.

-- Set the thumbwheel to "warm" at the Rear Temperature Selection Potentiometer -G538-.

The temperature of the air flowing from the rear center console vents rises again.

NOTE:

The temperature of the air flowing from the rear center console vent is regulated depending on the Rear Temperature Selection Potentiometer -G538- and the Climatronic Control Module -J255- setting, the air temperature tending only "colder" or "warmer" than that coming from the instrument panel vents.

-- Check the function of the Rear Temperature Selection Potentiometer -G538- using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function of the Climatronic Control Module -J255-.

If the specified values are reached, the test is complete.

Continuation For All

NOTE:

If the temperature for the driver side is set to "cold" and the temperature for the front passenger side is set to "warm", this test can be performed again using opposite measured values.

If the target values are not reached, check the following:

Check the activation and function of the various adjustment motors for the temperature doors in the A/C unit (depending on where the target values were not reached). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
Check the foam seal on the A/C system heater core for the heater (depending on where the target values were not reached). Refer to HEATER CORE, REMOVING AND INSTALLING .
Check the coolant circuit bleeding .
In vehicles with an Auxiliary Heater Heating Element -Z35-, check the separation between the left and right side in the A/C unit via the installation shaft for the Auxiliary Heater Heating Element -Z35-. Refer to Auxiliary Heater Heating Element -Z35-, REMOVING AND INSTALLING .
If equipped: check the activation and function of the Coolant Recirculation Pump -V50- and the Coolant Shut-Off Valve -N82-. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
On vehicles with a parking heater, check the activation and the function of the Recirculation Pump -V55- and the Heater Coolant Shut-Off Valve -N279-. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
Check the engine coolant pump for proper function (if the coolant pump is faulty or a Coolant Recirculation Pump -V50- / Recirculation Pump -V55- or Thermal Management Coolant Pump 2 -V618- on the Audi A6 e-tron is incorrectly integrated, there may be too little coolant flowing through the heater core for the heater in the front and rear A/C unit) .
Check the incorporation of the A/C system into the coolant circuit. Refer to COMPONENT LOCATION OVERVIEW - ENGINE COOLANT CIRCUIT .

Fault Finding In The Event Of A Temperature Increase After The Evaporator - In The A/C Unit

-- Clamp off both coolant hoses to the heater core, for example with :3093 . Refer to HEATER CORE, REMOVING AND INSTALLING .-- Repeat the heating output test and the activation of the temperature doors with the setting on "cold" on the control head. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION .-- Compare the measured value of the Evaporator Vent Temperature Sensor -G263- with the measured values of the Left Vent Temperature Sensor -G150-, Right Vent Temperature Sensor -G151-, Left Footwell Vent Temperature Sensor -G261- and Right Footwell Vent Temperature Sensor -G262-.-- Do the measured values of the temperature sensors match when the coolant hoses are clamped off, and are the required values reached?
↓ Yes ↓	↓ No ↓
-- Remove the :3093 from both coolant hoses.	-- Check the sensor with the deviating measured value for correct installation and check its electrical connections for contact resistance using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and Refer to the Appropriate Wiring Diagram.
↓
-- Check the activation and function of the Left Temperature Control Door Motor -V158- / Right Temperature Control Door Motor -V159-, the Rear Temperature Control Door Motor -V137- and the activation of each temperature door. Refer to AIR INTAKE AND OUTLET OPENINGS .	-- Correct the cause for the incorrect measured value, and if necessary, replace the defective sensor.
↓
Is the activation and functionality of the temperature control doors OK?
↓ Yes ↓	↓ No ↓
-- Check the function of the temperature door responsible for a temperature increase with setting at "cold". Refer to OVERVIEW - AIR DISTRIBUTION HOUSING DOORS AND PARTITIONS .-- Repeat the heating output test and the activation of the temperature doors. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION .	-- Correct the cause of the malfunction using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and the Approriate Wiring Diagram.-- Repeat the heating output test and the activation of the temperature doors. Refer to HEATING OUTPUT AND TEMPERATURE DOOR ACTIVATION, CHECKING, "Basic" VERSION .