spare wheel AUDI A6 ALLROAD 1999 C5 / 2.G Pneumatic Suspension System

17
Air supply
The compressor
The construction and function of the
compressor corresponds largely to the unit
described in the self-levelling suspension of
the A6. The following is a description only of
the differences in the 4-level air suspension
system in the Audi allroad quattro
•The fitting location is outside the vehicle
and without noise insulation (in front of
spare wheel well).
•The operating pressure is increased to
16 bar owing to the pressure accumulator
system.
243_028
•Lower speed for reduced noise.
•Suction and discharge of the air is
performed from the spare wheel well via
an air filter/noise damper (passenger
compartment).
•An additional noise damper in the suction/
discharge line ensures minimal through-
flow noise, particularly during discharge.
•Temperature monitoring is performed via
a temperature sensor at the cylinder head
and a simulation formula in the control
unit (temperature model) (more
information, see Temperature sensor
G290).
CompressorValve unit with
pressure sensor G291
Pneumatic discharge valve
Discharge valve N11 Air dryerTemperature sensor G290Additional noise damperTo the air filter/noise damper
Electric motor
Pressure pipeSuction/discharge line Electrical connector
Compressor drive

18
System components
A special mounting consisting of spiral
springs and rubber damping elements
prevents the transfer of vibrations to the
bodywork.
You can find a description of the design and
function of the compressor as well as the
filling and discharging procedure in SSP 242.
243_008
In normal operation the compressor is
allowed to run only when the engine is
running.
Exceptions:
–Final control diagnosis
–Basic system setting
–In pre-run upon recognition of an
extremely low level
Mounting
243_009
Spiral springDamping element
Air filter/noise damper
Owing to the fitting location of the air filter/
noise damper in the spare wheel well, it
requires no maintenance.