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Servicing refrigerant circuit > < Checking of front seat heating and ventilation

A4 Mk3

Checking air conditioner components on vehicles with a high-voltage system
Checking air conditioner components on vehicles with a high-voltage system
Hybrid vehicles
t  Air conditioner (and refrigerant circuit) components which are identical on vehicles with and without a high-voltage system can be checked, removed and installed as described for vehicles with no high-voltage system (e.g. the control motors at the air conditioning unit) → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051 (for air conditioner).
t  Air conditioner components which are largely identical on vehicles with and without a high-voltage system, but which may differ for example in terms of their function, can be checked, removed and installed as described for vehicles with no high-voltage system (e.g. the air conditioner operating and display unit, Climatronic control unit -J255-) → Electronic parts catalogue and → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051 (for air conditioner).
t  Air conditioner (and refrigerant circuit) components which differ on vehicles with and without a high-voltage system (e.g. the electrical air conditioner compressor -V470- with the control unit for air conditioning compressor -J842-) are to be checked, removed and installed as described for vehicles with a high-voltage system (e.g. -J842- with address word „40“ → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051). The control unit for air conditioning compressor -J842- (and thus the electrical air conditioner compressor -V470-) are supplied with power by the power and control electronics for electric drive -JX1-. -JX1- (address word „51“) is therefore also to be checked in the event of a problem → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051 and → Current flow diagrams, Electrical fault finding and Fitting locations
t  Air conditioner (and refrigerant circuit) components only fitted on vehicles with a high-voltage system (e.g. the electrical components of the battery cooling module, the refrigerant shut-off valve 1 for hybrid battery -N516- and the refrigerant shut-off valve 2 for hybrid battery -N517-) are removed and installed as described for vehicles with a high-voltage system. These components are not actuated directly by the air conditioner operating and display unit, Climatronic control unit -J255-. These components are actuated for example by way of the battery regulation control unit -J840- (with address word „8C“) → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051 and → Current flow diagrams, Electrical fault finding and Fitting locations.
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.
–  To minimise the number of automatic engine starts with READY active during checking and measurement work, the vehicle batteries must be charged e.g. with the Battery charger, 60A -VAS 5904- in battery back-up mode → Electrical system; Rep. gr.27 and → Electrical system; Rep. gr.93
–  Activate READY (with the ignition switched on, heed the display in the control unit in dash panel insert -J285-).
  Note
t  READY is displayed in the control unit in dash panel insert -J285- via the „Powermeter“.
t  Activate READY (and heed the display in the control unit in dash panel insert -J285-) → Owner's manual.
t  The selector lever is also to be set to position „P“ and the parking brake activated for checking and measurement work where the ignition has to be switched on but READY does not have to be active.
   

Servicing refrigerant circuit > < Checking of front seat heating and ventilation