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Removing and installing refrigerant pressure and temperature senderG395, checking signal > < Block diagram of refrigerant circuit components (not for vehicles with a high-voltage system)

A4 Mk3

Block diagram of refrigerant circuit components on vehicles with a high-voltage system
Block diagram of refrigerant circuit components on 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 „Warning notices for working on vehicles with a high-voltage system“ 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.
HD = High-pressure end
ND = Low-pressure end
Arrows show direction of refrigerant flow.
   
1 - Electrically driven air conditioner compressor
q   With control unit for air conditioning compressor -J842- and electrical air conditioner compressor -V470-
q   Detaching air conditioner compressor from holder/re-attaching on vehicles with a 4-cyl. engine → Chapter1)
  Note
t  The type of compressor may differ depending on the production period and engine. → Electronic parts catalogue
t  Not all replacement air conditioner compressors have the same oil capacity. Attention is therefore to be paid to the quantity of oil in the air conditioner compressor and the exact part number → Electronic parts catalogue and → Air conditioner with refrigerant R134a.
t  There may be different refrigeration oil capacities for the refrigerant circuit depending on the type of air conditioner compressor. The reason for the different oil quantities in the air conditioner compressor for an otherwise identical refrigerant circuit is the design of the actual air conditioner compressor. Attention is to be paid to these oil quantities. Too much oil in the refrigerant circuit results in higher pressures and a reduction in the cooling output of the air conditioner. Lubrication problems may be encountered in the air conditioner compressor if there is insufficient oil → Air conditioner with refrigerant R134a.
t  When fitting refrigerant lines and the corresponding holders, pay attention to adequate clearance from other components (such as belts and engine pulleys).
2 - Pressure relief valve
3 - Connection with valve
4 - Refrigerant pressure and temperature sender -G395-1)
q   Removing and installing → Chapter
q   For checking signal, refer to → Vehicle diagnostic, testing and information systemVAS 5051/, "Guided fault-finding" function
  Note
t  The refrigerant pressure and temperature sender -G395- uses a local data bus to exchange information with the onboard supply control unit -J519-. -J519- transmits the data via the data bus to the operating and display unit, Climatronic control unit -J255-. This vehicle is therefore not to be fitted with a high-pressure sender -G65- (only emits square-wave signals) → Electronic parts catalogue.
t  The temperature measured by the refrigerant pressure and temperature sender -G395- differs on account of the design of -G395- and its fitting location from the actual temperature of the refrigerant in the refrigerant circuit. At present this is therefore not evaluated and thus not used for air conditioner regulation.
5 - Condenser
q   Different versions → Electronic parts catalogue
6 - Receiver
q   The receiver is attached directly to the condenser → Chapter (removing and installing receiver)
q   Different versions → Electronic parts catalogue
7 - Cap
q   With seal
q   Always to be screwed on
8 - Service connection on high-pressure end
q   Different versions (with primary sealing valve or Schrader valve) depending on refrigerant line; distinguishing features → Air conditioner with refrigerant R134a
q   For air conditioner service station for measuring pressure and draining and filling refrigerant circuit → Air conditioner with refrigerant R134a
q   Depending on the engine version, certain components may have to be removed for connection of the service coupling.
  WARNING
The refrigerant circuit must be drained before removing the service connections (the connection has no valve).
  Note
Depending on the position of the service connection at the refrigerant line and the vehicle model, it may be necessary to remove the additional body brace stiffener on the left to permit connection of the service coupling of the air conditioner service station → Running gear; Rep. gr.40 and → Air conditioner with refrigerant R134a
9 - Connection to evaporator in battery cooling module
q   High-pressure end
  WARNING
The refrigerant circuit is to be drained before slackening off the bolts at the connection point.
10 - Expansion valve with refrigerant shut-off valve 2 for hybrid battery -N517-
q   At evaporator in battery cooling module
  Note
-N517- is actuated if battery needs to be cooled (closed without activation).
11 - Evaporator in battery cooling module
12 - Refrigerant shut-off valve 1 for hybrid battery -N516-
q   Fitted in area of left suspension strut dome in engine compartment
  Note
-N516- is actuated, for example, if the battery needs to be cooled but the air conditioner is not set to cooling mode for the passenger compartment (valve open without activation).
13 - Quick-release coupling of refrigerant line - high-pressure end
  WARNING
The quick-release couplings are only to be released and unfastened after draining the refrigerant circuit.
14 - Refrigerant line with internal heat exchanger
q   In this refrigerant line, the hot liquid refrigerant flowing on the high-pressure end supplies energy to the cold refrigerant vapour flowing on the low-pressure end, thus enhancing the efficiency of the air conditioner.
15 - Expansion valve
q   For evaporator in air conditioning unit
16 - Evaporator in air conditioning unit
17 - Quick-release coupling of refrigerant line - low-pressure end
  WARNING
The quick-release couplings are only to be released and unfastened after draining the refrigerant circuit.
18 - Connection to evaporator in battery cooling module
q   Low-pressure end
  WARNING
The refrigerant circuit is to be drained before slackening off the bolts at the connection point.
19 - Cap
q   With seal
q   Always to be screwed on
20 - Service connection on low-pressure end
q   Different versions (with primary sealing valve or Schrader valve) depending on refrigerant line; distinguishing features → Air conditioner with refrigerant R134a
q   For air conditioner service station for measuring pressure and draining refrigerant circuit → Air conditioner with refrigerant R134a
q   Depending on the engine version, certain components may have to be removed for connection of the service coupling.
  WARNING
The refrigerant circuit must be drained before removing the service connections (the connection has no valve).
  Note
Depending on the position of the service connection at the refrigerant line and the vehicle model, it may be necessary to remove the additional body brace stiffener on the left to permit connection of the service coupling of the air conditioner service station → Running gear; Rep. gr.40 and → Air conditioner with refrigerant R134a

   

Removing and installing refrigerant pressure and temperature senderG395, checking signal > < Block diagram of refrigerant circuit components (not for vehicles with a high-voltage system)