Audi Q3: Checking Pressures for Vehicles with Restrictor and Reservoir (with
Internally Regulated Compressor)
General Information
Note
- Connect the A/C service station. Refer to
→ Chapter "A/C Service Station, Connecting".
- Observe the test requirements. Refer to
→ Chapter "Pressures, Checking".
- With the ignition switched off, check the pressure in the
refrigerant circuit (using the service station). Refer to
→ Chapter "Refrigerant Circuit, Checking Pressure with Service
Station".
The pressures with the ignition turned off meet the
specifications.
- Start the engine.
- Bring the engine speed up to 2000 RPM.
- Observe the pressure gauge of the service station.
Note
- The switch pressures for refrigerant circuit switches are
vehicle-specific.
- The connection with valve for low-pressure switch or at
evaporator is only to be used for vehicles with no service
connection on low-pressure side and inaccessible connection at
compressor or accumulator (measurement accuracy). Only applies
to specific vehicles. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
Specified Values for the Refrigerant Circuit Pressures
High-Pressure Side:
Increasing from initial pressure (when connecting the
pressure gauges) to a maximum of 20 bar (290 psi).
Low-Pressure Side:
Decreasing from initial pressure (when connecting pressure
gauges) to the value in the graph.
A - High pressure (measured at service connection) in bar (psi)
B - Low pressure (measured at connection with valve at
compressor or accumulator) in bar
C - Permissible tolerance range
D - Low pressure (measured at connection with valve for
low-pressure switch or at service connection) in bar (psi)
E - Permissible tolerance range
Note
If no fault is found with this malfunction, clean the refrigerant
circuit (flush using refrigerant R134a. Refer to
→ Chapter "Refrigerant Circuit, Cleaning (Flushing), with Refrigerant
R134a"; or blow through using compressed air and nitrogen.
Refer to
→ Chapter "Refrigerant Circuit, Flushing with Compressed Air and
Nitrogen").
Note
- If problem involving moisture in refrigerant circuit only occurs
after a lengthy operating period or only infrequently (low pressure
drops below specification and evaporator ices up), it is sufficient to
replace the dryer (adjust quantity of refrigerant oil). Refrigerant
circuit is then to be evacuated for at least three hours.
- It is not initially necessary to clean the refrigerant circuit
(flush using refrigerant R134a. Refer to
→ Chapter "Refrigerant Circuit, Cleaning (Flushing), with Refrigerant
R134a". Or blow through using compressed air and nitrogen.
Refer to
→ Chapter "Refrigerant Circuit, Flushing with Compressed Air and
Nitrogen" when this problem occurs since normally there is
only a small quantity of moisture in the system which can be removed by
lengthy evacuation.
Note
- For the malfunction "high pressure normal, low pressure too low",
note the following: This fault may cause the evaporator to ice up or the
A/C Refrigerant Low Pressure Switch -F73- to shut off the compressor
although the amount of refrigerant in the circuit is OK.
- On the Audi 100, Audi A6 (through MY1997) and Audi V8, this fault
may result in compressor being shut off by the control head (if the
temperature at fresh-air blower drops below -3 ºC (27 ºF) ). Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview
- Refrigerant Circuit or
→Heating, Ventilation and Air Conditioning; Rep. Gr.87
(vehicle-specific repair manual).
Note
- Overfilling with refrigerant oil can occur if, for example, the
compressor has been replaced without adjusting the quantity of
refrigerant oil.
- If there is too much refrigerant oil in the circuit, the compressor
must be drained and the accumulator must be replaced. After cleaning the
refrigerant circuit (flushing with refrigerant R134a. Refer to
→ Chapter "Refrigerant Circuit, Cleaning (Flushing), with Refrigerant
R134a"; or blowing through using compressed air and nitrogen.
Refer to
→ Chapter "Refrigerant Circuit, Flushing with Compressed Air and
Nitrogen"), the correct quantity of refrigerant oil is filled
into the circuit. Refer to
→ Chapter "Approved Refrigerant Oils and Capacities".
READ NEXT:
General Information
Note
Connect the A/C service station. Refer to
→ Chapter "A/C Service Station, Connecting".
Observe the test requirements. Refer to
→ Chapter "Pres
Specified Values for the Refrigerant Circuit Pressures
Note
Connect the Air Conditioning (A/C) service station. Refer to
→ Chapter "A/C Service Station, Connecting".
Observe th
General Information
Note
Connect the Air Conditioning (A/C) service station. Refer to
→ Chapter "A/C Service Station, Connecting".
Observe the test requirements. Refer to
→
SEE MORE:
Connector Component Location Overview
1 - Right Front Door Cut-Off Connector
Disconnecting. Refer to
→ Chapter "Left Door Cut-Off Connector, Disconnecting".
2 - Right Rear Door Cut-Off Connector
Disconnecting. Refer to
→ Chapter "Left Door Cut-Off
Snow chains improve both driving and braking in
winter road conditions.
Only install snow chains on the front wheels.
Check and correct the seating of the snow
chains after driving a few feet, if necessary. Follow
the instructions from the manufacturer.
Note the maximum speed of 30 mph
(50 km