Audi A4: Heating, Ventilation & Air Conditioning
Audi A4 (B9) 2016-2026 Service Manual / Heating, Ventilation & Air Conditioning
- Warnings when Working on Vehicles with High Voltage System
- A/C System, General Information
- Introduction
- A/C Technology Basic Principles
- Refrigerant R134a
- Refrigerant R134a Characteristics
- Refrigerant Oil
- A/C System Operation
- General Safety Precautions
- A/C System and Refrigerant R134a Safety Precautions
- Refrigerant Circuit, General Precautions
- Refrigerant Circuit General Information
- Vehicles with a High Voltage System (Hybrid Vehicles)
- Refrigerant Circuit Components Allocation, High and Low Pressure Sides
- Refrigerant Circuit
- Connections for Quick-Release Coupling on Refrigerant Circuit
- Switches and Sensors on Refrigerant Circuit and Connections
- Refrigerant Circuit Pressures and Temperatures
- Pressure Gauge, Tests and Measurements
- Service and Recycling Units
- Laws and Regulations
- Refrigerant Circuit
- A/C System Repair Information
- Using Service Station
- Refrigerant Circuit, Flushing with Compressed Air and Nitrogen
- Refrigerant Circuit, Cleaning (Flushing), with Refrigerant R134a
- Refrigerant Circuit, Determining Leaks
- Refrigerant Circuit Complaints
- A/C Service Station, Connecting
- General Information
- Service Station, Connecting with Connections on Low- and High Pressure Side of Refrigerant Circuit
- Service Station, Connecting with No Connection on Low- and High Pressure Side of Refrigerant Circuit
- Pressures, Checking
- General Information
- Refrigerant Circuit, Checking Pressure with Service Station
- Checking Pressures for Vehicles with Restrictor and Reservoir (with Internally Regulated Compressor)
- Checking Pressures on Vehicles with Expansion Valve and Receiver/Dryer (with Internally Regulated Compressor)
- Vehicles with Restrictor, Reservoir and A/C Compressor Regulator Valve -N280- (Externally Regulated A/C Compressor), Checking Pressures
- Vehicles with Restrictor, Receiver/Dryer and A/C Compressor Regulator Valve -N280-, Checking Pressures, Externally Regulated Compressor
- Checking Pressures on Vehicles with Electrically Driven A/C Compressor (Vehicles with Hybrid Drive)
- Refrigerant Circuit Components, Replacing
- General Information
- Leaking or Damaged Components except A/C Compressor, Reservoir or Receiver/Dryer
- Compressor, Replacing without the Need for Flushing Refrigerant Circuit
- Compressor, Replacing on Account of Leakage or Internal Damage
- Receiver/Dryer or Accumulator and Restrictor, Replacing after Cleaning Refrigerant Circuit
- A/C Compressor Regulator Valve -N280-, Removing and Installing
- Refrigerant R134a Capacities, Refrigerant Oil and Approved Refrigerant Oils
- Tools and Equipment
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Warnings when Working on Vehicles with High Voltage System
Vehicles with a High-Voltage System (Hybrid Vehicles)
Working on Vehicles with High-Voltage System (Hybrid Vehicles)
Extremely Dangerous Due to High-Voltage
The high-voltage system is under high-volta
Introduction
The purpose of this repair manual is to provide service
advisors and technicians with the basic knowledge needed to
ensure professional and competent procedures.
Note
Only the careful study
SEE MORE:
Backrest Adjuster, Removing and Installing
Backrest Adjustment Hand Wheel, Removing and Installing
Special tools and workshop equipment required
Assembly Tool -3399-
Removing
- Move the front seat all the way forward into its highest
position.
- Turn the backrest adjustment wheel -1-
until one catch is visible from behind
-ar
A/C Technology Basic Principles
Physical Principles
The four known states of water also apply to air
conditioning system refrigerants.
1 - Gaseous (invisible)
2 - Vapor
3 - Liquid
4 - Solid
When water is heated in a container (heat absorption), water
vapor can be seen to rise. If the vapo
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