Heating Output And Temperature Control Door Activation, Checking: Notes
For these vehicles (For example the Audi A4) there are different versions of the A/C system depending on the equipment. Make sure to use the correct version and pay attention to the allocation of different components. Refer to HEATING AND A/C SYSTEM VERSIONS and Parts Information.
For vehicles with a "Low" A/C system a Front A/C Display Control Head -E87- -A- is installed in the rear and not a Rear A/C Display Control Head -E265-.
For vehicles with a "High" A/C system a Front A/C Display Control Head -E87- -B- (upper illustration) and a Rear A/C Display Control Head -E265- -A- is installed.
-- 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, if equipped, the vents in the rear center console.
-- Close the vent for glove compartment cooling (in the glove compartment) (If equipped).
-- Turn on the ignition and activate the ready mode. The engine starts automatically as needed (on vehicles with a Start/Stop System).
-- Start the engine.
Set The Following On The Front A/C Display Control Head -E87- :
By selecting the "SYNC" function on the Front A/C Display Control Head -E87- (only for version -B-) the settings of the front driver side and the front passenger side and also on the Rear A/C Display Control Head -E265- are transferred.
- If equipped, adjust the SYNC mode on the Front A/C Display Control Head -E87-.
- Select "Auto" mode (for the driver side and the front passenger side) (the indicator lamp in the AUTO button(s) turns on).
- "Cold" temperature preset (16 °C (60.8 °F) for the "Low" A/C system).
- "Cold" temperature preset for the driver and front passenger side ("LO" display for the driver and front passenger side for the "High" A/C system and the MMI).
- The A/C compressor is on (the indicator lamp in the A/C MAX button turns on).
- Preset for the fresh air blower "maximum speed".
- Set the airflow direction of the air via the knob on the Front A/C Display Control Head -E87-, to "footwell" and "instrument panel vent" (on a "Low" A/C system).
- Set the airflow direction of the air via the knob or button on the Front A/C Display Control Head -E87- for the driver and front passenger side to "footwell" and "instrument panel vent" (on "High" A/C system) (appears in the display or the button from the Front A/C Display Control Head -E87-).
For a "High" A/C system, the following is set on the Rear A/C Display Control Head -E265- :
- "Cold" temperature setting ("LO").
For these vehicles (For example the Audi A4) there are different versions of the A/C system depending on the equipment. Make sure to use the correct version and pay attention to the allocation of different components. Refer to HEATING AND A/C SYSTEM VERSIONS and Parts Information.
On vehicles with a "High" A/C system the air temperature and amount of air that is calculated and regulated by the Front A/C Display Control Head -E87- is also influenced by the setting on the Rear A/C Display Control Head -E265-. On this Rear A/C Display Control Head -E265- only one temperature is adjustable. Refer to REAR A/C DISPLAY CONTROL HEAD -E265-, REMOVING AND INSTALLING, "HIGH" A/C SYSTEM, A4 AND A5 .
On vehicles with a "High" A/C system the temperature of the air to the vents in the front area is measured via the Left Rear Footwell Vent Temperature Sensor -G637- (installed in the left rear footwell air duct) and the Rear Upper Body Vent Temperature Sensor -G537- (installed in the intermediate piece in the air duct to the vent in the rear center console).
Continuation For All Versions
The indicator lamps in the AUTO buttons turn off 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 (coolant temperature, electrical system voltage, etc.)
The instrument panel vent and the rear center console vents are open.
-- Initiate Guided Fault Finding for the heating and A/C system and select the "Read measured values" function. Use the Vehicle Diagnostic Tester.
-- Let the A/C system run a few minutes at maximum cooling output (A/C compressor is switched on, indicator lamp in the A/C MAX button comes on).
-- Compare the measured value of the Evaporator Vent Temperature Sensor -G263- with the measured values of the Left Front Upper Body Vent Temperature Sensor -G385-, the Left Footwell Vent Temperature Sensor -G261- on a "Low" A/C system.
-- Additionally on a "Low" A/C system measure the temperature from the left and right instrument panel vent air coming out using a thermometer.
The Left Front Upper Body Vent Temperature Sensor -G385- is installed on a "Low" A/C system in the air duct to the instrument panel vent "center". To determine the temperate of the air from the right and left instrument panel vent, it is helpful to measure the temperature of these vents with the thermometer.
-- On vehicles with a "Low" A/C system: compare the measured value of the Evaporator Vent Temperature Sensor -G263- with the measured values of the Left Front Upper Body Vent Temperature Sensor -G385- and the Left Footwell Vent Temperature Sensor -G261- and the temperature measured with the thermometer.
-- On vehicles with a "High" A/C system: compare the measured value of the Evaporator Vent Temperature Sensor -G263- with the measured values of the Left Front Upper Body Vent Temperature Sensor -G385-, the Right Front Upper Body Vent Temperature Sensor -G386-, the Left Footwell Vent Temperature Sensor -G261-, the Right Footwell Vent Temperature Sensor -G262-, the Left Rear Footwell Vent Temperature Sensor -G637- and the Rear Upper Body Vent Temperature Sensor -G537-.
-- Additionally on a "High" A/C system measure the temperature of the air coming out from the right rear footwell vent using a thermometer.
The Rear Upper Body Vent Temperature Sensor -G537- and Left Rear Footwell Vent Temperature Sensor -G637- are only installed on vehicles with a "High" A/C system (with a Rear A/C Display Control Head -E265-).
SPECIFIED VALUES:
- The measured values of the temperature sensor (after the heat exchanger), Left Front Upper Body Vent Temperature Sensor -G385-, Left Footwell Vent Temperature Sensor -G261- and the temperature measured with the thermometer on a "Low" A/C system must after 5 minutes be a maximum 10 °C greater than the value of the Evaporator Vent Temperature Sensor -G263-.
- The measured values of the temperature sensor (after the heat exchanger), Left Front Upper Body Vent Temperature Sensor -G385-, Right Front Upper Body Vent Temperature Sensor -G386-, Left Footwell Vent Temperature Sensor -G261-, Right Footwell Vent Temperature Sensor -G262-, Left Rear Footwell Vent Temperature Sensor -G637-, Rear Upper Body Vent Temperature Sensor -G537- and the temperature measured with a thermometer on a "High" A/C system after 5 minutes must be a maximum 10 °C (50 °F) greater than the value of the Evaporator Vent Temperature Sensor -G263-.
Due to the design of the heater and A/C unit and the air routing in the vehicle, there is always a certain increase in air temperature.
- If the required values on a "Low" A/C system are not reached, perform a fault finding at a temperature increase on the evaporator. Refer to FAULT FINDING IN THE CASE OF A TEMPERATURE INCREASE DOWNSTREAM FROM THE EVAPORATOR (IN THE HEATER AND A/C UNIT) .
- If the required values on a "High" A/C system on the temperature sensors Left Front Upper Body Vent Temperature Sensor -G385-, Right Front Upper Body Vent Temperature Sensor -G386-, Left Footwell Vent Temperature Sensor -G261-, Right Footwell Vent Temperature Sensor -G262- are not reached perform a Fault Finding downstream from evaporator. Refer to FAULT FINDING IN THE CASE OF A TEMPERATURE INCREASE DOWNSTREAM FROM THE EVAPORATOR (IN THE HEATER AND A/C UNIT) .
If the measured value at one or more temperature sensors or a vent 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.
-- "Warm" temperature preset (28 °C (82.4 °F) for a "Low" A/C system).
-- "Warm" temperature preset for the driver and front passenger side on the Front A/C Display Control Head -E87- ("Hi" display on the "High" A/C system).
-- For a vehicle with a "High" A/C system, set the temperature to "warm" using the buttons on the Rear A/C Display Control Head -E265- ("Hi" in the display for the Rear A/C Display Control Head -E265-).
-- Let the A/C system run for several minutes at the maximum heating output.
For these vehicles (For example the Audi A4) there are different versions of the A/C system depending on the equipment. Make sure to use the correct version and pay attention to the allocation of different components. Refer to HEATING AND A/C SYSTEM VERSIONS and Parts Information.
On vehicles with a Front A/C Display Control Head -E87- the version -B- the settings on the front driver side are applied to the front passenger side and also to the Rear A/C Display Control Head -E265- by selecting the "SYNC" function. The display for the preselected temperature changes for all vents (the driver and front passenger side and for the rear) from "LO" to "HI".
-- In the function "read measured values" of the Guided Fault Finding from the Front A/C Display Control Head -E87- displayed measured values, reads out the different temperature sensors. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
-- For vehicles with a "Low" A/C system: compare the measured values of the Left Front Upper Body Vent Temperature Sensor -G385-, Left Footwell Vent Temperature Sensor -G261- and the temperature measured with the thermometer.
-- For vehicles with a "High" A/C system: compare the measured values of the Left Front Upper Body Vent Temperature Sensor -G385-, Right Front Upper Body Vent Temperature Sensor -G386-, Left Footwell Vent Temperature Sensor -G261-, Right Footwell Vent Temperature Sensor -G262-, Left Rear Footwell Vent Temperature Sensor -G637-, Rear Upper Body Vent Temperature Sensor -G537- and the temperature measured using a thermometer.
Specified Values:
- The measured temperature for all temperature sensors increases to above 50 °C (122 °F) (depending on the engine temperature at the time).
The Left Front Upper Body Vent Temperature Sensor -G385- is installed on a "Low" A/C system in the air duct to the instrument panel vent "center". To determine the temperate of the air from the right and left instrument panel vent, it is helpful to measure the temperature of these left and right vents with the thermometer.
For vehicles with a Start/Stop System, the Coolant Recirculation Pump -V50- / Recirculation Pump -V55- maintains the coolant flow through the heater core for the heater in the heater and A/C unit when the engine is not running.
The component location of the Coolant Recirculation Pump -V50- varies. It is installed in the plenum chamber on the majority of vehicles with a 4-cylinder engine, and installed in the engine compartment on the majority of vehicles with a 6-cylinder engine (for example, under the right fender). Refer to COOLANT CIRCUIT and ELECTRIC COOLANT PUMP, REMOVING AND INSTALLING .
The activation of the Coolant Recirculation Pump -V50- is different. In most vehicles, it is activated by the respective Engine Control Module -J623- at the request of the Front A/C Display Control Head -E87-. Refer to Vehicle Diagnostic Tester in the "Guided Fault Finding" function and refer to the appropriate Wiring Diagram(s).
The Required Values Are Achieved At All Temperature Sensors:
- On vehicles with a "Low" A/C system (Front A/C Display Control Head -E87- version -A-) the test is ended.
- Continuation for checking on vehicles with a "High" A/C system the version -B- Front A/C Display Control Head -E87- (see the upper illustration) and a version -A- Rear A/C Display Control Head -E265-. Refer to CONTINUATION FOR ALL VEHICLES WITH A "HIGH" A/C SYSTEM, CHECK THE SEPARATION FOR THE TEMPERATURE CONTROL BETWEEN THE LEFT AND RIGHT SIDE IN THE HEATER AND A/C UNIT. . (Check the separation for the temperature control between the left and right side in the heater and A/C unit).
For vehicles with a "Low" A/C system no Rear A/C Display Control Head -E265- is installed.
For vehicles with a "High" A/C system a Rear A/C Display Control Head -E265- -A- is installed. Refer to Rear A/C Display Control Head -E265-, REMOVING AND INSTALLING, "High" A/C SYSTEM, A4 AND A5 .
If the required values are not reached on any of the temperature sensors:
- Check the activation and function of the Coolant Recirculation Pump -V50- (of the Recirculation Pump -V55-) and of the Coolant Shut-Off Valve -N82- (of the Heater Coolant Shut-Off Valve -N279-). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
- Check the incorporation of the A/C system into the coolant circuit. Refer to INCORPORATING THE HEATING AND A/C SYSTEM IN THE COOLANT CIRCUIT .
- Check the coolant circuit bleeding. Refer to COOLANT, DRAINING AND FILLING .
- Check the heating output of the A/C system at an engine speed of approximately 1500 to 2000 RPM (repeat the test at a higher engine speed). If the required heating output is reached at this engine speed, the malfunction is not in the heater and 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 heater core in the heater and A/C unit, incorporation of the Coolant Recirculation Pump -V50- into the coolant circuit, etc.). Refer to INCORPORATING THE HEATING AND A/C SYSTEM IN THE COOLANT CIRCUIT and COOLANT, DRAINING AND FILLING .
- Check that the engine coolant pump is functioning correctly (if a coolant pump is faulty or a Coolant Recirculation Pump -V50- is incorporated incorrectly, there may not be enough coolant flowing through the heater core for the heater in the heater and A/C unit). Refer to OVERVIEW - ELECTRIC COOLANT PUMP .
For vehicles with an engine with a regulated coolant circuit (for example, with a regulated coolant pump and a Cylinder Head Coolant Valve -N489-), there is currently no Coolant Shut-Off Valve -N82- installed. On an engine with a regulated coolant pump, the engine control module activates the coolant pump, and in doing so regulates the coolant circulation.
If the required values are not reached at only one or two temperature sensors:
- Check the activation and function of the various actuators for the temperature control doors in the heater and 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.
- Perform Fault Finding if there is an increase in temperature after the evaporator. Refer to FAULT FINDING IN THE CASE OF A TEMPERATURE INCREASE DOWNSTREAM FROM THE EVAPORATOR (IN THE HEATER AND A/C UNIT) .
- Check the foam seal on the heat core for the heater for the heater and A/C unit. 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 heater and A/C unit via the installation shaft for the Auxiliary Heater Heating Element -Z35-. Refer to Auxiliary Heater Heating Element -Z35-, REMOVING AND INSTALLING .
- Check the coolant circuit bleeding. Refer to COOLANT, DRAINING AND FILLING .