Audi A4: 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.

• For all procedures on vehicles with high-voltage system pay attention to the additional warning message for these vehicles. Refer to → Chapter "Warnings when Working on Vehicles with High Voltage System".
• If procedures are necessary near components of the high-voltage system "perform a visual inspection of the damage of the high-voltage components and lines". Refer to → Chapter "Performing a Visual Inspection of Damage to High Voltage Components and Cables".
• If work on the components of the high-voltage system is necessity, de-energize the high-voltage system. Refer to → Rep. Gr.93; High-Voltage System, De-Energizing or → Electrical Equipment; Rep. Gr.93; High-Voltage System, De-Energizing.

- 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; Battery, Charging and → High Voltage Vehicle General Information; Rep. Gr.93; High-Voltage System General Warnings.

- For testing and measurement procedures that require the ready mode to be active or the ignition to be switched on, the selector lever must be in the "P" position and the parking brake must be activated. The required tools must be placed so that they do not come into contact with any rotating components in the engine and they must also not go into the vicinity of the rotating components when the engine is running.

  Note

• Also move the selector lever into position "P" and activate the parking brake for testing and measuring procedures which require the ignition to be on, but do not require the ready mode to be active.
• The ready mode is displayed in the Instrument Cluster Control Module -J285- above the "power meter". Refer to Owner's Manual
• For activating and deactivating the ready mode, refer to the Owner's Manual (while doing so, note the display in the Instrument Cluster Control Module -J285-).

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

  WARNING

There is a risk of freezing.

Refrigerant may leak out if refrigerant circuit is not discharged.

Refrigerant must be extracted before opening the refrigerant circuit. If refrigerant circuit is not opened within 10 minutes of extraction, pressure may form in refrigerant circuit due to evaporation. Extract the refrigerant again.

• All components of the refrigerant circuit submitted for quality observation are always to be sealed (use original sealing caps of replacement part).
• To date, the following replacement parts (A/C compressor, reservoir, receiver/dryer, evaporator and condenser) have been filled with nitrogen gas. This charging stops gradually or the charging pressure is so low that gas does not escape noticeably when opening.
• On vehicles installed with a compressor with no A/C clutch, the engine is only to be started following complete assembly of the refrigerant circuit (compressor always in operation as well) .
• When the refrigerant circuit is empty, the A/C compressor with A/C Compressor Regulator Valve -N280-(without A/C clutch) is switched to internal lubrication with the result that only a minimal amount of oil is pumped from the compressor into the circuit.

  Note

• As parts are sometimes stored for lengthy periods and at different locations within the spare parts organization, it is entirely possible that gas will escape from some parts and not from others on initial opening (even in the case of identical spare part numbers). Sealing caps at replacement part connections are therefore to be removed carefully and the nitrogen gas allowed to escape slowly.
• The refrigerant circuit is equipped either with a restrictor and a reservoir, or with an expansion valve and receiver/dryer.
• The dryer cartridge or components with dryer bag (reservoir, receiver/dryer) are always to be replaced after cleaning the refrigerant circuit by flushing with 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". In doing so, leave sealed as long as possible to minimize absorption of moisture.
• The dryer cartridge or components with dryer bag (reservoir, receiver/dryer) are to be replaced if it is required for certain repair manual operations or if the refrigerant circuit has been open for a lengthy period and moisture has penetrated (for example, following an accident). Refer to → Chapter "Leaking or Damaged Components except A/C Compressor, Reservoir or Receiver/Dryer".
• The period of time which a refrigerant circuit may be left open without having to replace a component with the dryer bag (reservoir, receiver/dryer) depends on ambient influences to a large extent. Given a high ambient temperature and a high humidity level or if the vehicle, for example, has been standing in the open or driven (in wet, foggy weather conditions), the period will be considerably shorter than for a vehicle which has been standing in a heated dry area. The size of the opening through which moisture may ingress into the circuit also influences the period for which a refrigerant circuit can be left open without having to replace the component with the dryer bag. Refer to → Chapter "Leaking or Damaged Components except A/C Compressor, Reservoir or Receiver/Dryer".
• Seal open connections and pipes (to prevent absorption of moisture).
• Always replace the restrictor.

  Caution

Dispose of dirty or used oils of unknown origin paying attention to local regulations.

READ NEXT: