Audi A4 2005 - Running Gear; Brake System Specifications; ESP System Features

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Running gear
Brake system
The A4 `05 models with 120 and 147 kW four-cylinder engines have 16-inch brake systems. The Teves FNRG 60
16-inch frame-design caliper brake is already being used in the A6 and A8. This system was optimised for the
A4 and specially adapted for the new vehicle.
The CII-41 floating caliper brake on the rear axle originates from the S4 `04. The brake was adapted for use in
the A4 `05 by reducing the piston diameter to 41mm, and a solid brake disc is used.
The brake control mechanism is unchanged from the previous model.
Units Front suspension Rear suspension
Brake disc
(Ø x thickness)
Brake caliper Brake disc
(Ø x thickness)
Brake caliper
1.6-litre 75 KW 280x22
vented
TRW
C54
245x10
solid
TRW
C38
Four-cylinder
85 - 103 kW
280x25
vented
ContiTeves
FN3-57 15"
245x10
solid
TRW
C38
1.8-litre 120 kW 312x25
vented
ContiTeves
FN3-57 15"
245x12
solid
TRW
C38
All six-cylinder
2.0-litre TFSI
320x30
vented
ContiTeves
FNRG-60 16"
288x12
solid
TRW
CII-41 16"
4.2-litre V8 345x30
vented
ContiTeves
FNRG-60 17"
300x22
vented
TRW
CII-43 17"
ESP
As previously in the A6 `04, the new-generation
system Bosch 8.0 ESP system is also featured on the
A4 `05 (see SSP 324). The fundamental difference in
design between the A4 and A6 systems is the use of
passive wheel speed sensors.
In addition to the familiar subfunctions, the A4`06 has a new function called Hydraulic Fading Compensation
(HFC). By comparing the brake pressures at which ABS system begins to operate, the system can detect brake
fading at an early stage. The greater the fading, the higher the brake pressure needed to activate the ABS
system.
If fading is detected, ESP raises the overall pressure in the system by building up additional brake pressure.
The driver does not need to apply more pressure to the brake pedal, in order to achieve the same braking
effect as with fading-free brakes.
The "hill-holder" function implemented for the A6 `05 models with multitronic transmission is not available for
the A4 `05 from launch.
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