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.

  Note

The procedure for finding leaks in the refrigerant circuit using an electronic leak detector or a UV-leak detection lamp can be performed on most high-voltage system components without needing to disable the high-voltage system.

- 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.

  Note

• Minor leaks can be detected using an electronic leak detector or UV leak detector lamp.
• This repair manual describes two different methods for detecting leaks in the refrigerant circuit. These methods have been tested and result in success when used correctly.
• Many methods for detecting leaks in the refrigerant circuit are offered in the open market. These methods do not always have optimum results and if they are not performed exactly to the specification and may result that several components in the refrigerant circuit have leaks. Also, refrigerant circuit components can be damaged by some methods.
• Do not repair components with leaks; always replace them.
• Do not charge a leaking refrigerant circuit with refrigerant. Evacuate the circuit and check it for leaks before charging. Refer to → Chapter "Refrigerant Circuit, Discharging with Service Station".

  Caution

• Audi does not approve the use of chemicals to seal leaks in the refrigerant circuit (leak stop additives).
• Chemicals that seal leaks in the coolant circuit form deposits that affect the function of the A/C system and lead to A/C system failure (and failure of the A/C service station).

  Note

Chemical materials (leak stop additives) to seal leaks in the refrigerant circuit react with air or the moisture in the air and form deposits in the refrigerant circuit (and in the A/C service station) that lead to malfunctions in the valves and other components that come into contact with such chemicals. These deposits cannot be removed completely from the components, even by flushing. It is only possible to service the refrigerant circuit by replacing all the components which come in contact with this material.

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