Audi A4 Owners & Service Manuals

Audi A4: Brakes

General information

You can apply the vehicle's brakes using the brake pedal.

Operating noise

Noises may occur when braking depending on the speed, braking force, and outside conditions such as temperature and humidity.

Braking effect

The response time from the brakes depends on the weather and environmental conditions. To ensure the optimal braking effect, the brake system is cleaned at regular intervals. This is done by applying the brake pads to the brake rotors for a short period of time when driving at high speeds when the windshield wipers are switched on.

If the brake system becomes damp, for example after driving in heavy rain, the braking effect may be delayed. Other factors that could temporarily increase the response time of the brakes include:

  • Wet conditions
  • Low temperatures, ice, and snow
  • Roads covered in salt
  • Dirty brake pads

Corrosion

Corrosion may form on the brake rotors if there is no heavy braking, if the vehicle is not driven for long periods of time, or if the vehicle is not driven frequently or for long distances. In this case, braking heavily several times while driving at high speeds can clean the brake rotors.

Brake pads

New brake pads do not achieve their full braking effect during the first 250 miles (400 km). They must be "broken in" first. However, you can compensate for the slightly reduced braking force by pressing firmly on the brake pedal. Avoid heavy braking during the break-in period.

Brake pad wear depends largely on the way the vehicle is driven and on operating conditions.

Brake pad wear increases when driving frequently in the city or short distances or when using a very sporty driving style.

Ceramic brakes

Applies to: vehicles with ceramic brakes

Ceramic brakes provide excellent deceleration rates.

The break-in period for new ceramic brakes may be significantly longer than for standard brake rotors. The properties of the material may also cause noise, especially when driving at lower speeds. Ceramic brakes also absorb more moisture in wet conditions. Therefore, there will temporarily be less braking force than when the brakes are dry. You can compensate for this by pressing the brake pedal harder.

Automatic post-collision braking system

The automatic post-collision braking system can help to reduce the risk of sliding and of additional collisions after an accident. If the airbag control module detects a collision, the vehicle is braked by the ESC.

The vehicle does not brake automatically if one of the following occurs:

  • The driver presses the accelerator pedal, or
  • The braking force generated by the pressed brake pedal is greater than the braking force that would be initiated by the system
  • The ESC, the brake system, or the vehicle electrical system is not functioning

WARNING

  • Only apply the brakes for the purpose of cleaning the brake system when road and traffic conditions permit. You must not endanger other road users and increase the risk of an accident.
  • Due to the risk of injury, only have an authorized Audi dealer or authorized Audi Service Facility work on the brake system.

    Incorrect repairs could impair the function.

  • Never let the vehicle roll while the engine is stopped because this increases the risk of an accident.
  • During automatic braking maneuvers, the brake pedal may move downward automatically.

    To reduce the risk of injury, do not place your foot under the brake pedal.

Note

  • Never let the brakes "rub" by pressing the pedal lightly when braking is not actually necessary. This can cause the brakes to overheat and increases braking distance and causes wear.
  • Observe the important information for driving downhill. This especially applies when towing a trailer.

Tips

  • If you retrofit your vehicle with a front spoiler, wheel covers or similar items, make sure that the air flow to the brakes is not obstructed.

    Otherwise the brake system can overheat.

  • Also refer to the information about brake fluid .

Messages

The following messages may appear depending on the vehicle equipment:

Brakes: malfunction! Safely stop vehicle There is a malfunction in the brake system. If and also turn on, there is a malfunction in the ABS, ESC, and braking distribution. If the brake booster is not working, you have to use much more force when braking the vehicle.

Do not continue driving. See an authorized Audi dealer or authorized Audi Service Facility for assistance.

Read and follow the other safety precautions.

Brake pads: wear limit reached. You can continue driving. Please contact Service

The brake pads are worn. Drive to an authorized Audi dealer or authorized Audi Service Facility as soon as possible to have the malfunction corrected.

Brake booster: limited functionality. You can continue driving. Please contact Service

There is a brake booster malfunction. The brake booster is available, but its effectiveness is reduced.

The braking performance may be different compared to the usual performance. Drive to an authorized Audi dealer or authorized Audi Service Facility immediately to have the malfunction corrected.

Brake booster: deactivated. See owner's manual

The brake booster remains active for a brief period of time after switching off the ignition. Secure the vehicle against rolling.

Other indicator lights

When you switch the ignition on, the indicator light turns on briefly to check the function.

If the indicator light does not turn on, there is a system malfunction.

If stays on, there is a malfunction in the brake system.

A high load was placed on the brakes from driving downhill for a long period of time. Follow the instructions in the message to utilize the engine braking effect and to relieve the brakes.

WARNING

If a malfunction occurs in the ABS, ESC, and braking distribution, interventions that stabilize the vehicle will no longer be available.

This could cause the vehicle to swerve, which increases the risk that the vehicle will slide.

Do not continue driving. See an authorized Audi dealer or authorized Audi Service Facility for assistance.

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