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Removing and installing heat exchanger > < Removing and installing heat exchanger of air conditioning unit

A4 Mk3

Preparation for heat exchanger removal
Preparation for heat exchanger removal
–  Switch on the ignition.
–  Set the air outflow direction on the air conditioner operating and display unit, Climatronic control unit -J255- to „DEF“ (to windscreen).
–  Move the front passenger's seat to the rearmost position.
–  Switch off the ignition.
Vehicles with a high-voltage system (hybrid vehicles)
For all work on vehicles with a high-voltage system, pay attention to the additional warnings for such vehicles → Chapter and → Electrical system; Rep. gr.93.
  WARNING
Danger from unexpected engine starting
When performing general work on vehicles with a high-voltage system, switch off the ignition and remove the ignition key from the passenger compartment.
  WARNING
Working on vehicles with high-voltage wiring:
l  Do not support yourself or tools on high-voltage wiring or associated components --> this can damage the insulation.
l  High-voltage wiring must not be excessively bent or kinked --> this can damage the insulation.
l  The round high-voltage connectors are colour-coded with an external coloured ring and are provided with mechanical coding or guide lugs. It is important to observe this coding when joining up the round high-voltage connectors, otherwise the connectors can be damaged.
  DANGER!
Risk of fatal injury if high-voltage components are damaged.
Observe the following when working in the vicinity of high-voltage components or wiring:
t  It is not permitted to use cutting or forming tools, other sharp-edged tools or heat sources such as welding, brazing, soldering, hot air or thermal bonding equipment.
t  Before starting work, visually inspect the high-voltage components in the areas involved.
t  Before working in the engine compartment, visually inspect the power electronics -JX1-, electric drive motor -V141-, air conditioner compressor -V470- and high-voltage wiring.
t  Before working on the vehicle underbody, visually inspect the high-voltage wiring and covers.
t  Before working on the rear section of the vehicle, visually inspect the high-voltage wiring and the electro-box with the maintenance connector for high-voltage system - TW -.
t  Visually inspect all potential equalisation lines.
Check the following when making the visual inspection:
t  There must be no external damage on any component.
t  The insulation of the high-voltage wiring and potential equalisation lines must not be damaged.
t  There must be no unusual deformation of the high-voltage wiring.
t  All high-voltage components must be identified by a red warning sticker.
As work on the high-voltage system is required for the following sequence of operations, the high-voltage system has to be isolated from the supply → Chapter, → Electrical system; Rep. gr.93 and attention is to be paid to the „General warnings for working on high-voltage system“ → Electrical system; Rep. gr.93
–  Isolate the high-voltage system from the supply → Electrical system; Rep. gr.93
Isolation of high-voltage system from supply
  DANGER!
High voltage can cause fatal injury.
Danger of severe or fatal injuries from electric shock.
t  Voltage levels in the high-voltage system constitute a safety hazard.
t  For reasons of safety, persons with life-preserving or other electronic medical devices in or on their body must not perform any work on the high-voltage system. Such medical devices include internal analgesic pumps, implanted defibrillators, pacemakers, insulin pumps and hearing aids.
t  The high-voltage system may only be de-energised by a suitably qualified person (Audi high-voltage technician).
t  It must be definitely confirmed that the high-voltage system is de-energised. The system may only be de-energised using the vehicle diagnostic tester via „Guided Fault Finding“.
t  The qualified person (Audi high-voltage technician) confirms that the system is de-energised and uses the locking cap -T40262- to ensure that the system cannot be re-energised. The ignition key and the maintenance connector for high-voltage system - TW - should then be stored in a safe place by the qualified person.
t  The qualified person (Audi high-voltage engineer) attaches signs to mark the vehicle accordingly.
  Note
t  Isolation of high-voltage system from supply:
t  Connect the vehicle diagnostic tester
t  Select Guided fault-finding mode
t  Use the Go to key to consecutively select the following menu items
t  Function/component list
t  Body
t  Electrical system
t  Systems with self-diagnosis capability
t  8C - Hybrid battery management -J840
t  8C - Hybrid battery management, functions
t  51 - Isolation of high-voltage system from supply (Rep. Gr. 93)
–  Detach the earth connection from the battery -A- → Electrical system; Rep. gr.27.
   
–  Remove the rubber seal -A- and the plenum chamber cover -B- (different versions) → General body repairs, exterior; Rep. gr.50.
t  After removing the plenum chamber cover -B-, visually inspect the high-voltage components -D- (in this case the power and control electronics for electric drive -JX1-) and the high-voltage cables -E- → Chapter and → Electrical system; Rep. gr.93
–  Remove the scuttle panel trim -C- → General body repairs, exterior; Rep. gr.50
–  Detach the earth connection from the battery -A- → Electrical system; Rep. gr.27.
  A87-11116
–  Unfasten the potential distributor -1- and set down together with the wiring towards the windscreen → Electrical system; Rep. gr.93
–  Detach the high-voltage cables to the electrical air conditioner compressor -V470- and from the drive battery -A2- from the power and control electronics for electric drive -JX1- → Electrical system; Rep. gr.93.
–  Cover -JX1- and the corresponding wiring to guard against damage or contamination → Electrical system; Rep. gr.93
  Note
  A93-10008
For covering the connections at -JX1--A-, use can be made for example of clean size 20 sealing plugs -B- from the engine bung set -VAS 6122-.
  A87-11248
t  When working in the area of high-voltage components -D- and high-voltage cables -E- always make sure that these components are not damaged → Electrical system; Rep. gr.93.
t  On completion of work and before fitting the plenum chamber cover -B-, visually inspect the high-voltage components -D- and the high-voltage cables -E- → Electrical system; Rep. gr.93.
Vehicles with no high-voltage system
–  Remove the plenum chamber cover (not always necessary, different versions) → General body repairs, exterior; Rep. gr.50.
–  Detach the earth connection from the battery -A- → Electrical system; Rep. gr.27.
  Note
  A87-11116
The earth connection of the battery -A- is detached to prevent short circuits with the jump start socket -C- detached.
–  Remove the cover for the jump start socket -C-.
–  Detach the jump start socket -C- from the body brace and lay aside → Electrical system; Rep. gr.27.
All vehicles
–  Remove the air intake box → Chapter.
–  Unplug the connector from the evaporator output temperature sender -G263- → Chapter.
–  Remove the right heater housing → Chapter.
t  Remove the heat exchanger → Chapter.
  A87-10515

Removing and installing heat exchanger > < Removing and installing heat exchanger of air conditioning unit