General Information
Vehicles with a high-voltage system (hybrid vehicles)
Extremely Dangerous Due to High-Voltage
The high-voltage system is under high-voltage. Death or serious bodily injury by electric shock.
- Individuals with electronic/medical life- and health sustaining machines in or on their person cannot perform any work on high-voltage systems. Life- and health sustaining machines are for example pain killer pumps, implanted defibrillators, pacemakers, insulin pumps, and hearing aids.
- Have the high-voltage system de-energized by a qualified person.
There is a Risk of Injury from the Engine Starting Unexpectedly
On electric - hybrid vehicles an active ready mode is difficult to identify. Parts of the body can be clamped or pulled.
- Turn off the ignition.
- Place the ignition key outside of the vehicle interior.
Risk of Damaging the High-Voltage Cables
Misuse can damage the insulation of high-voltage cables or high-voltage connectors.
- Never support objects on the high-voltage cables and the high-voltage connectors.
- Never support tools on the high-voltage cables and the high-voltage connectors.
- Never sharply bend or kink the high-voltage cables.
- When connecting pay attention to the coding of the high-voltage connectors.
- Charge the vehicle battery, for example, using the Battery Charger -VAS5904- in the battery support mode to minimize the number of automatic starts during the test- and measuring procedures while the ready mode is active. Refer to → Electrical Equipment General Information; Rep. Gr.27; Battery; Charging the Battery and → Electrical Equipment; Rep. Gr.93; General Notes for Working on the High Voltage System.
- Move the selector level into position "P", activate the parking brake and arrange the necessary tools for testing and measuring procedures that require the ready mode to be active or that require the ignition to be on, so that they cannot come into contact with the turning components in the engine and so that they are not in the vicinity of the turning components of a running engine.
Note
Vehicles with Start/Stop System
There is a Risk of Injury from the Engine Starting Unexpectedly
The engine can start unexpectedly on vehicles with an activated Start/Stop System. A message appears in the instrument cluster indicating whether the Start/Stop System is activated.
- Deactivate the Start/Stop System: Turn off the ignition.
All Vehicles
Caution
Note
If the refrigerant circuit gets filed with a chemical material (stop leak additive) to seal any leaks (or if there is a suspicion of this) and if it then necessary to perform a repair to the refrigerant circuit, then it is necessary to inform the customer of the following:
Service Station, Important Usage Information
Observe the following with regard to service station operation. Refer to the Parts Catalog (Tools; Special Tools and Equipment: A/C and Heating).
- The filters and dryers installed must be replaced at the latest on completion of the service life specified in the relevant operating instructions.
- If a service station is also used for cleaning (flushing) the refrigerant circuit, dryer and filter must be replaced in shorter intervals. Refer to → Chapter "Refrigerant Circuit, Flushing with Compressed Air and Nitrogen".
- Only refrigerant oils which have been approved for the refrigerant circuit in that vehicle may be added (if necessary, fill refrigerant oil directly into refrigerant circuit). Refer to the Parts Catalog.
Extracted refrigerant is not to be reused if there is any doubt about the composition of the refrigerant extracted, even after cleaning in the service station.
- The service station is to be drained in all these cases. Refer to → Chapter "A/C Service Station, Connecting"). The system is cleaned if necessary and the filters, dryers and refrigerant oil are replaced.
- For example, within Germany, contaminated refrigerant can be returned to the supplier in recycling containers for recycling or for environmentally safe disposal. Other or additional regulations may apply in other countries.
Commercially available service stations can be classified in two groups:
A/C Service Station, Connecting for Measuring and Testingv
Note
The work procedure is always to be performed as described in the operating instructions for the A/C service station.
The charging hoses are to be connected as follows to prevent the ingress of air or moisture into the refrigerant circuit:
- Turn off the ignition.
- Connect the service station to the power supply.
- Remove the caps from the service connections or connections with valve. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; System Overview - Refrigerant Circuit (vehicle-specific repair manual).
- Evacuate the charging hoses if necessary.
- Connect the quick-release coupling to the refrigerant circuit service connection.
WARNING
Never open valves on low or high-pressure side with the engine running. Otherwise, compressor or service station could be destroyed by a short circuit between high and low-pressure sides of refrigerant circuit if air conditioning system is switched on.
- Only tighten the handwheel in the quick-release coupling just enough so the service connection is open. Watch the pressure gauge and do not place too much pressure on the valve.
- Start the engine and perform the planned tests and measurements.
- Compare values determined to specified measured values. Refer to → Chapter "Pressures, Checking".
- Before disconnecting the quick-release coupling, close it by screwing out the hand wheel.
Vehicles with Only One Service Connection:
Note
Install the A/C Adapter Set - Adapter 9 -VAG1785/9-, A/C Adapter Set - Adapter 10 -VAG1785/10- or A/C Adapter Set -VAG1786- onto the connections with the refrigerant circuit valve and bleed the charging hoses while connecting to the adapters (faintly audible escape of refrigerant gas is permitted). Refer to → Chapter "A/C Service Station, Connecting".
- The charging hose must be installed with a valve opener for opening valve in valve adapter.
On vehicles with high-voltage system and additional functions of the A/C system (for example on Audi Q7 e-tron):
Note
On vehicles with the "heat pump" function and/or "high-voltage battery cooling" in not all operating conditions is the A/C system high pressure on the service connection of the high pressure side. The refrigerant circuit pressure on the high pressure side can on these vehicles depending on the operating conditions of the A/C system, can only be measured via the pressure/temperature sensor installed in the refrigerant circuit. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; Refrigerant Circuit; System Overview - Refrigerant Circuit and use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
To check the different functions of these A/C systems
- Select the respective function ("cooling the vehicle interior", "heat pump operation" or "cooling the high-voltage battery") via the Vehicle Diagnostic Tester and perform the respective specifications using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
- Select the measured values of the different pressure/temperature sensor installed in the refrigerant circuit and read out. Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.