ECO mode AUDI A6 ALLROAD 1999 C5 / 2.G Pneumatic Suspension System

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243_023
243_024
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Other button functions
Automatic switching
The so-called “manual mode” can be
switched on or off by pressing the “raise” or
“lower” button for at least 3 sec. The yellow
LED marked “man” indicates to the driver that
the vehicle is in manual mode.
The automatic “parking level control” and
“motorway mode” functions are deactivated
in manual mode.
Switching off control system
The control system is switched on or off by
pressing both level buttons for longer than
5 seconds.
When the control system is switched off, the
LEDs in the operating unit for manual mode,
both level buttons and the warning lamp K134
are illuminated.
The level-indicating LEDs show the level set.
The corresponding LED is continuously
illuminated.
A control system that has been switched off
will be automatically switched back on again
when the driving speed exceeds approx.
10 km/h (unless the lifting platform mode is
recognised).
The control system can also be switched off
using the diagnostic testers (see Workshop
Manual).
It is often advisable to switch off the
system during repair work (e.g. during
axle measurement or if the pressure
lines have been detached) in order to
prevent the compressor from running
unnecessarily.
Display example: Manual mode and NL
Display example: Raising from LL to HL1
Display example: Raising from HL1 to HL2
Display example: Lowering from NL to LL

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If the vehicle is at high level 2, it will lower
automatically to high level 1 at a speed of
> 35 km/h. The system will respond to a
request to shift to high level 2 only up to a
speed of < 30 km/h.
At a speed of > 80 km/h in high level 1, the
system will automatically lower the vehicle to
normal level.. The system will respond to a
(manual) request to shift to high level 1 only
up to a speed of < 75 km/h.
During driving operation, no automatic
raising to high level 1 or 2 is performed. It
must be selected manually by the driver.
The parking level is an exception. In this
mode the vehicle automatically rises to high
level 1 once it has been parked and locked
(see parking level control). There are two control units currently in use,
depending on the country.
The control strategies described below relate
to the control unit 4Z7 907
553A.
The differences in control units with part
numbers 4Z7 907
553B
are described
subsequently.
See also page 34, “Self-levelling control unit
J197”.
Control strategies
4Z7 907 553A
Automatic lowering
As mentioned previously, the driver can select
the appropriate level by actuating the “raise”
or “lower” buttons.
The following preconditions relating to
driving speed apply for high level 1 and high
level 2.
Control strategies
0 35 80 120
0
5 35 70 120

Automatic lowering
Lowering processes
after 30 seconds
after 30 seconds
Raising processes
after 120 seconds
Raising to parking level
Immediate raising Speed km/h
Speed km/h
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LL NL HL1HL2
LL NL HL1HL2

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Motorway mode
If the vehicle travels for longer than
30 seconds at over 120 km/h (vehicle is
already at normal level), it will automatically
be lowered to low level.
This reduces air resistance (saves fuel) and
lowers the vehicle’s centre of gravity
(improved driving dynamics).
PL (=HL1) is only cancelled when a
driving speed of 80 km/h is exceeded
(see automatic lowering) or when
switching to a lower level manually.
If the vehicle is already in HL2 it is not
lowered to parking level.
Manual mode
The motorway mode and parking level
control functions are deactivated in
manual mode (see Automatic
switching page 9).
The vehicle rises automatically to normal level
at the following speeds and time thresholds:
Vehicle speed Time
<70 km/h >120 seconds
<35 km/h >30 seconds
<5 km/h immediately

Parking level control
The parking level ensures that the vehicle is
maintained at a suitable level after parking for
a long period of time (normal volumetric
reduction due to cooling or diffusion).
It also facilitates entering and loading the
vehicle and optimises the appearance of the
stationary vehicle.
The parking level corresponds to high level 1
(HL1).
The vehicle is set to parking level
–when the system is in run-on mode and the
vehicle is locked from the outside.
–when sufficient pressure is present in pres-
sure accumulator.
–when the system is not switched to manual
mode.

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Control strategies
The vehicle rises automatically to high level 1
at the following speeds and time thresholds:
If the system has lowered the vehicle to low
level (motorway mode), it will automatically
raise it to high level 1 when its speed drops
below 60 km/h for longer than 30 seconds.Vehicle speed Time
<60 km/h >30 seconds
<30 km/h immediately
Control unit strategies
4Z7 907 553B
Variations to the description of control unit
4Z7 907 553A are outlined below:
•No parking level control
•Automatic raising to high level 1
Preconditions for automatic raising to high
level 1:
•The system must not be switched to
manual mode.
•Between ignition ON and OFF, the driver
must select high level 1 or high level 2
once.
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Automatic lowering
Lowering processes
after 30 seconds
Automatic raising to HL1 after
30 seconds
Raising processes
Immediate raising Speed km/h
Speed km/h LL NL HL1HL2
LL NL HL1HL2

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Level change process:
Raising - rear axle first, then front axle
Lowering - front axle first, then rear axle
Modes
Height mode/driving mode
Reaction times upon level deviation
Control characteristics during level change
Level change is basically performed axle by
axle, whereby level differences between the
left and right sides are compensated (e.g. if
loaded on one side).Driving speed Reaction time
<5 km/h
Height modeapprox. 5 seconds
approx. 1 second at
extremely low level
>10 km/h
Driving modeapprox. 50 seconds or
15 minutes
depending on the level
deviation
Run-on mode/run-up mode
The run-on mode enables the compensation
of level deviations after the vehicle has been
parked (e.g. caused by passengers leaving the
vehicle or unloading the vehicle) and before
driving off (e.g. caused by intense cooling,
leakage or loading).
In this mode, delay times before commencing
a journey are kept to a minimum.After “Ignition OFF”, the control unit is in the
so-called run-on mode. The control unit
remains active for a maximum of 15 minutes
(via terminal 30) until it goes into sleep mode.
Due to the limited energy available when the
engine is switched off, control limits are
extended and controls are limited in both
number and duration.

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Control concepts
The system can switch between sleep mode
and run-on/run-up mode, triggered via the
door contact signal, a maximum of 15 times.
For the 15 subsequent wake-up procedures,
the system switches to sleep mode after only
1 minute.
The system can then only be activated via
terminal 15 and/or the speed signal. Sleep mode
To minimise electricity consumption the
control unit switches to “system idle” (sleep
mode) after 15 minutes.
There is no level adjustment in sleep mode.
“Wake-up” is primarily triggered by the door
contact signal. If the door contact signal fails,
the system is activated when the ignition is
switched “ON” or by the driving speed signal.
The vehicle should be raised as quickly
as possible in order for the control unit
to recognise the lifting-platform mode.
It is often advisable to switch off the
system during repair work (e.g. during
axle measurement or if the pressure
lines have been detached, in order to
prevent the compressor running
unnecessarily).
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Lifting platform mode
The control unit evaluates the level signals
while a stationary vehicle is being lowered
and thereby initiates lifting platform
operating mode.
The aim of the lifting platform mode is to
prevent excessive discharge of the air springs
when the vehicle is completely raised.

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In trailer operation, normal mode must
always be selected and care must be
taken that the system is switched to
manual mode (e.g. no automatic
switching to manual mode if trailer
operation signal fails).
In difficult driving conditions, high
level 1 or high level 2 can be selected,
however, normal level must be selected
before a driving speed of 35 km/h is
exceeded.
Driving at low level or in automatic
mode is not permitted.
Trailer operation
The correct position of the tow bar on the
trailer attachment during trailer operation is
indicated in normal mode.
Contact switch F216 in the 13 pin trailer
socket is used to signal that the trailer plug is
inserted, i.e. indicates trailer operation (see
description “Trailer operation signal”.
If trailer operation is recognised, the manual
mode is automatically activated (LED “man”
lights up) whereby the automatic raising
process is stopped.
Normal level is set by the driver via control
unit E281.
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Normal level

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Allroad quattro control strategies
4-level air suspension + additional shift stage
0203580 60
5100 120 130 200
30
General overview
Control unit 4Z7 907 553A/B
ESP safety-switching
Automatic lowering
Parking level
control
v >70 km/h: Engine intervention
v >50 km/h: Acoustic and visual warning in low range
Air supply: control primarily via
pressure accumulator <36 km/hVehicle speed v
in km/h
v <30 km/h: shift to low range possible
Additional shift stage
Air supply: control primarily via compressor >36 km/h
Pressure accumulator filled >36 km/h
Motorway mode:Lowering: >120 km/h >30 seconds
Raising: <70 km/h >120 seconds
<35 km/h >30 seconds
<5 km/h immediately
Manual mode:- no parking level control
- no motorway mode
- automatic lowering from HL2
and HL1; ESP safety-
switching remains active
Automatic mode:- parking level control (HL1)
- motorway mode:
- automatic lowering from HL2 and HL1.
- ESP safety-switching
LL NL HL1 HL2243_040
Control unit 4Z7 907 553B: Automatic mode:- no parking level control
- automatic raising to HL1
<60 km/h >30 seconds
<30 km/h immediately