Audi A4: 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 of this documentation, practical implementation of the information contained, training on A/C systems and expert knowledge (with or without certificate) can guarantee expertise in the field of motor vehicle A/C systems.

This document is a compact reference work which should be kept at the workplace. It should also be available to the current supervising authority upon request.

Vehicles with a High-Voltage System (Hybrid Vehicles)

Extremely Dangerous Due to High-Voltage

The high-voltage system is under high-voltage. Electrocution can cause death or very serious personal injury from damages high-voltage components and high-voltage cables.

- Perform a visual inspection of the high-voltage components and the high-voltage cables.

- Never use tools that are for cutting, deformed, or sharp edged.

- Never use welding, soldering, thermal adhesive or hot air.

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 work 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".

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

Non-approved tools or materials (such as leak stop additives) can cause damage or malfunctions in the system.

Only use tools and materials approved by the manufacturer.

The warranty is void if non-approved tools or materials are used.

Safety Precautions for Vehicles with Start/Stop System

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.

Additional Information Sources

• Repair manual for model-specific maintenance. Refer to → Heating, Ventilation and Air Conditioning; Rep. Gr.87; Component Location Overview - Air Conditioning (vehicle-specific repair manual) and → Wiring diagrams, Troubleshooting & Component locations.
• Technical Service Handbook outlining action to be taken to rectify current problems
• Self-Study Program, for example Self Study Program 208; A/C Systems in Vehicle
• Video programs for in-dealership training
• Special tools and workshop equipment needed to service the A/C system. Refer to the Parts Catalog (Tools; Special Tools and Equipment: A/C and Heating).
• Repair manual Air Conditioning with Refrigerant R12 (only hard copies of this manual are available for vehicles through MY 1993).

Vehicles with a High Voltage System (Hybrid Vehicles)

For all procedures on vehicles with high-voltage system pay attention to the warning message for vehicles with high-voltage system. Refer to → Chapter "Warnings when Working on Vehicles with High Voltage System".

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