Note. Due to space limitation when the instrument panel is installed, it is not possible to install the factory-installed heat exchanger and clamps -B- and -C- again. If a factory installed heat exchanger (Original part) must be installed again, remove the instrument panel and the air guide leading to the Defrost vent. Coat the O-rings with coolant (as described for installing an exchange part - heat exchanger) and mount them on the coolant pipes -D- and -E-, and then push the coolant pipes -D- and -E- (with the O-rings) from the top into the connections on the heat exchanger -A-. Hold the coolant pipes -D- and -E- in the heat exchanger and install the clamps -B- and -C-. Further assembly is performed as described for installing a replacement part - heat exchanger.

Release pressure in cooling circuit by opening cap on coolant expansion tank. .

Mark the arrangement of coolant hoses -A- (supply to cylinder head) and -B- (return to coolant pump).

Note. The heat exchanger is designed for a specific coolant flow direction. Therefore, coolant hoses must be connected on the correct sides. Bleed the coolant circuit. Refer to A/C UNIT HEAT EXCHANGER .

Clamp the coolant hoses -A- and -B- with hose clamps.

Cover the area beneath connections for coolant hoses -A- and -B- e.g. with absorbent paper.

Remove coolant hoses -A- and -B- from connections to A/C unit heat exchanger. Refer to A/C UNIT HEAT EXCHANGER or refer to Removal and Installation .

Insert one section each of hose -A- and -B- on to both connections to heater core.

Place a container -B- under the other end of the hose -C-.

Using a compressed air gun -D-, carefully blow coolant out of heater core (into container -B-) via hose -A-.

Remove the clamps -B- and -C- from the heat exchanger connectors -A-.

Scheme 397

Loosen both coolant pipes -D- and -E- from the heat exchanger connectors -A-.

Remove the heat exchanger -A- in the direction of the arrow -arrow-.

Note. The upper illustration shows a heat exchanger with connectors as it is installed in production. If the heat exchanger was already exchanged once, then both coolant pipes are held in the replacement heat exchanger with a bracket -A-. Remove the screw -B- in this heat exchanger. Install a longer screw -C- (with a M5 thread) all the way to the end as shown in the illustration and with this screw, loosen the bracket -A- from the connection.

Installing

Installation is carried out in the reverse order, when doing this note the following

Depending on the A/C version, cover the heat exchanger with the foam seal provided -A- through -D-.

Scheme 398

1 - Heat exchanger for a vehicle equipped with a Basis A/C system with left- or right-hand drive.

2 - Heat exchanger for a vehicle equipped with a Comfort A/C system with LHD.

3 - Heat exchanger for a vehicle equipped with a Comfort A/C system with right-hand drive.

Check the seals on the heat exchanger; only install a heat exchanger with seals that are not damaged and are secured glued on.

Note. If the vehicle has the Comfort A/C system, then there are different temperature settings for the right and left sides as well as for the rear. The seals -C- and -D- separate the air guides in the air conditioner from each other. Refer to AIR ROUTING AND DISTRIBUTION IN PASSENGER COMPARTMENT . The heat exchanger has a color mark that shows where to affix the seal -C-. The seal -D- must be applied to the center of the heat exchanger as illustrated. The seal -C- may have different lengths (a short version as illustrated or a long version which reaches all the way around the heat exchanger). If the heat exchanger is delivered with the longer seal -C-, then attach it all the way around the exchanger. Seal may curl up on insertion if not correctly bonded on. If the seal is damaged or installed incorrectly, cold air can flow over the heat exchanger; on vehicles equipped with the Comfort A/C system, it is possible that there is no clear separation between the various areas.

Check the A/C unit and the evaporator -F- with the heat exchanger removed -A- (via heater core opening) for dirt.

Remove any dirt or coolant which has leaked out of the A/C unit (for example, after removing a leaking heat exchanger).

Check both connections -A- and -B- on the heat exchanger -C- for damage and dirt.

Scheme 399

Grease both connections -A- and -B- on the heat exchanger -C- with silicone grease.

Note. The silicone grease part number is G 000 405 A2. Refer to Electronic Parts Information.

Lightly moisten the seals -D- (contained in the heat exchanger delivery) with coolant (or lightly with silicone grease).

Scheme 400

Install the new seals -D- on both heat exchanger coolant pipes -E- and -F-.

Push the heat exchanger -A- into the A/C unit.

Scheme 401

Support the heat exchanger -A-, for example, with a plastic wedge -B- on the center tunnel -C- so that it cannot slip down when attaching the coolant pipes.

Install a longer screw -G- (with a M5 thread) all the way to the stop in the bracket -C- as shown in the illustration.

Install and push both coolant pipes -E- and -F- with each seal -D- into the heat exchanger connector flange all the way. -H-.

Note. Do not bend the coolant pipes -D- and -E- when pushing them into the connections on the heat exchanger.

Make sure the seals -C- between the coolant pipes -D- and -E- and the flange connection -B- on the heat exchanger -A- fit securely.

CAUTION

Seals that are incorrectly installed or jammed -C- will leak. The seals -C- must be installed completely into both the coolant pipe connections -D- and -E- and the flange connections -B-.

Secure both coolant pipes -E- and -F- with the bracket -C- on the heat exchanger flange -H-.

Note. The screw -G- is used to help with the installation and must be removed after the bracket is installed.

Insert the screw -A- and the washer -B- and tighten the screw -A-.

Screw tightening specification -A- 2.5 Nm.

Remove the screw -G-.

Make sure the grommet -H- fits correctly in the back of the plenum chamber.

Properly connect the coolant hoses to the heat exchanger, pay attention to the marking.

A - Supply hose from cylinder head

B - Return to the coolant pump

Connect the coolant hose -A- to the heat exchanger coolant pipe (pay attention to the marking) and secure it with the clamp -D-.

Attach the coolant hose for the heat exchanger -B- onto the coolant pipe -F- just far enough as to not cover the bleed hole -G-.

Remove the hose clamp from the coolant hose -A-.

Fill the coolant overflow reservoir with coolant. Refer to General Information .

Carefully force the coolant out of the coolant overflow reservoir into the heat exchanger using, for example, the hand pump from the V.A.G 1274/.

As soon as the coolant comes out the ventilation hole -G-, install the coolant hose -B- on to the coolant pipe -F- at the marking.

Secure the coolant hose -B- with the clamp -E- on the marked location.

Remove the hose clamp from the coolant hose -D-.

If necessary, add more coolant overflow reservoir with coolant. Refer to General Information .

Note. By this procedure, the cooling system is not completely bled. If, for some other reason, there still should be some air in the cooling system, install all the components and bleed the system once again. Refer to General Information .

Check The Connections On The Heat Exchanger For Leaks As Follows

Carefully increase the pressure in the cooling system by using, for example, the hand pump from the V.A.G 1274/.

Check coolant circuit for leaks, pay particular attention to the connection between coolant hoses and heater core. Refer to General Information .

Note. When bleeding coolant circuit, take special care to ensure complete bleeding of heat exchangers. If there are still air bubbles in the heater core, it may cause the customer to complain of insufficient heating performance in winter or different air temperature from vents at same setting in regulated mode. Refer to HEAT OUTPUT AND TEMPERATURE DOOR ACTIVATION, TESTING REQUIREMENTS . Depending on vehicle equipment and on engine, heat insulation has been applied to coolant hoses, these must not be damaged and must be re-applied after installing.

Install all the components in reverse sequence, refer to PREPARING FOR REMOVAL .

Reconnect the Battery ground connection; when doing this, pay attention to the notes regarding reconnecting the battery. Refer to Removal and Installation .

Perform a basic setting and the output Diagnostic Test Mode (DTM) on the A/C system using the Vehicle Diagnosis, Testing and Information System VAS 5051 under "Guided Fault Finding".

Note. On this vehicle, the control motors are equipped with electronics. During the first basic setting, a new control motor learns its position on the air conditioner and can then be controlled by the Climatronic Control Module -J255- (currently all control motors are identical). Refer to Vehicle Diagnosis, Testing and Information System VAS 5051 under "Guided Fault Finding" During the basic adjustment, the control motors are assigned and adapted corresponding to the switching sequence of the wiring. If this sequence does not conform to the specification, the control motors will adapt incorrectly and the door control will be wrong. Refer to A/C CONTROL MOTOR BLOCK DIAGRAM .

Check the Climatronic Control Module -J255- DTC memory and erase any displayed malfunction if necessary using the Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Adjust and check the air flow direction on the different air ducts via Climatronic control module, if the quantity of air actually changes at each setting.

Special tools and workshop equipment required

Hook 3438

The Climatronic Control Module -J255

Note. In both versions (Basis or Comfort) the Climatronic Control Modules are removed and installed in the same way.

Removing

Check the Climatronic Control Module coding and adaptation using the "Replace Control Unit" function the Guided Fault Finding (if the Climatronic Control Module should be replaced) using Vehicle Diagnosis, Testing and Information System VAS 5051 under "Guided Fault Finding".

CAUTION

To prevent damage to the Climatronic control module and center console, do not pull too hard. Do not damage surface of center console when removing (cover it if necessary).

Switch off ignition.

Attach the 3438 -B- in one of the openings -C- or -D- in the Climatronic control module -A- according to the illustration.

Scheme 402

Carefully pull the Climatronic control module in the -direction of arrow- out of center console.

Note. The Climatronic control module is held in the center control brackets with clamps (left and right).

Disconnect the Climatronic control module connectors

Loosen the harness connector release catch -C- for the connectors -A- and -B- by pulling the direction of the arrow -arrow-.

Scheme 403

Press the connector release catch -D- -arrow- and remove the connectors -A- and -B-.

Installing

Installation is carried out in the reverse order, when doing this note the following.

When replacing the Climatronic control module be sure to pay attention to precise assignment. Refer to «CLIMATRONIC CONTROL MODULE ALLOCATION»(/audi/a4/b8-2007-2012/remont/automatic-hvac-system/#air-conditioning-avant__climatronic-control-module-allocation) and Electronic Parts Information.

Mount the trim to the A/C control head on the Audi Q5.

Clean the adhesive surface -D- on the A/C control head -A- for example with cleaning solution D 009 401 04. Refer to Electronic Parts Information.

Install the Climatronic control module -A-.

Note. The trim piece -B- is supplied with a two-sided adhesive strip already installed -C-. Refer to Electronic Parts Information. If the trim piece -B- is going to be re-used when replacing the Climatronic control module -A-, then remove the adhesive strip -C- from the trim -B-. Clean the adhesive surface on the trim -B- as described in the instructions which came with the adhesive strip. Affix to the trim piece -B- a strip (dimension: 204 mm x 10 mm) of the two-sided adhesive strip -C- with material strength approximately 1.2 mm (for example with adhesive tape D 438 515 A1. Refer to Electronic Parts Information).

Mount the trim piece -B- with the adhesive tape -C- onto the adhesive surface -D- on the A/C control head -A- and the align it -B-.

Press the trim piece -B- onto the surface -D-.

After replacing / installing the Climatronic control module, always perform the following work using the Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

Re-code (or check the coding) of the Climatronic control module.

Perform the basic setting, Climatronic control module.

Check DTC memory of Climatronic control module (correct the cause for any malfunctions displayed) and erase.

Check the adaptation of the Climatronic control module and correct if necessary.

Perform the Output Diagnostic Test, Climatronic control module (depending on the type of complaint).

PREPARING FOR REMOVAL Audi A4 B8