2006 Alfa Romeo 156 sensor

GETTING TO KNOW YOUR CAR
180
The heart of the VDC system is the VDC
control unit which with the data supplied by
the sensors installed on the car, calculates
the centrifugal forces generated when the
car is cornering. The yawing sensor detects
the rotations of the car around its own ver-
tical axis. The centrifugal forces generated
when the car is cornering are detected by
a highly sensitive lateral acceleration sensor.
The stabilising action of the VDC system is
based on calculations made by the
system’s electronic control unit which
processes the signals received from the
steering wheel rotation, lateral acceleration
and individual wheel rotation sensors. These
signals allow the control unit to recognise
the manoeuvre the driver intends to do
when turning the steering wheel.
The control unit processes the information
received from the sensors and is therefore
capable of detecting the position of the car
and comparing it with the trajectory the dri-
ver would like to follow instant by instant.
In the event of a discrepancy, the control
unit chooses and commands the most suit-
able action to bring the car back to the re-
quired course within a fraction of a second:
braking one or more wheels at a different
braking force and, if necessary it reduces the
power transmitted by the engine. The corrective actions are changed and con-
trolled continuously until the car returns to
the required course.
The action of the VDC system considerably
increases the active safety of the vehicle un-
der many critical situations and it is partic-
ularly useful also when the road surface grip
conditions change.
For the VDC, ASR and ABS
systems to work correctly,
the tyres must be of the same
brand and type on all wheels, in
perfect conditions and above all of
the specified type, brand and size.
WARNING
During use of the compact
spare wheel, the VDC sys-
tem continues working. It should be
borne in mind that the spare wheel
is smaller than a normal tyre,
therefore its grip is lower than that
of the other tyres of the car.
WARNING
VDC SYSTEM OPERATIONThe VDC system turns on automatically
when the car is started and cannot be
switched off. It is however possible to cut
off operation of the ASR system pressing the
corresponding button on the centre console.
The main components of the VDC system
are:
– an electronic control unit which
processes the signals received from the var-
ious sensors and brings about the most ap-
propriate strategy;
– a sensor that detects the position of the
steering wheel;
– four sensors that detect the rotation
speed of each wheel;
– a sensor that detects rotation of the car
around the vertical axis;
– a sensor that detects lateral acceleration
(centrifugal force).

GETTING TO KNOW YOUR CAR
187
ENVIRONMENTAL
PROTECTIONThe design and construction of the vehi-
cle have not only been developed with the
traditional aspects of performance and
safety in mind, but also take into account
the increasingly pressing problems tied to
protecting the environment.
The choice of materials, techniques and
particular parts are the result of work which
has made it possible to drastically reduce
the harmful effects on the environment and
guarantee respect for the severest interna-
tional norms.USE OF NON-TOXIC
MATERIALSNone of the components of the vehicle con-
tains asbestos. The padding and the climate
control system do not contain CFCs which
are held to be responsible for the depletion
of the ozone layer.
The colouring agents and the corrosion in-
hibitors used on the nuts, screws and bolts
do not contain cadmium any more, which
could pollute the atmosphere or water tables.
PARKING SENSORS
(WHERE PROVIDED)(optional for versions/markets
where applicable)
The parking system detects and informs
the driver (through an intermittent acoustic
signal) about the presence of obstacles in
the rear part of the car (fig. 179). ACTIVATIONThe sensors are automatically activated
when the reverse gear is engaged.
The sound produced by the acoustic alarm
becomes continuous when the distance be-
tween the car and the obstacle is less that
30 cm.
ACOUSTIC SIGNALWhen the reverse gear is engaged an in-
termittent acoustic signal is automatically
activated.
The acoustic signal:
– raises with the reduction of distance be-
tween the car and the obstacle;
– becomes continuous when the distance
between the car and the obstacle is less that
30 cm and stops if the distance raises.
– is constant if the distance is unvaried.
If this situation takes place for side sensors,
the signal is stopped after about 3 seconds
to prevent sound indications when per-
forming manoeuvres near walls.fig. 179
A0B0609m

GETTING TO KNOW YOUR CAR
188
EMISSION REDUCING DEVICES
(petrol engines)Trivalent catalytic converter
(catalytic silencer)
The exhaust system is fitted with a cat-
alyzer formed of alloys of noble metals. It
is housed in a stainless steel container which
is able to resist the high operating temper-
atures.
The catalyzer converts the unburnt hydro-
carbons, carbon monoxide and nitrogen ox-
ides present in the exhaust gas (even if in
small quantities thanks to the electronic in-
jection and ignition system) into harmless
compounds.Lambda probe
A sensor (lambda probe) measures the
content of oxygen present in the exhaust
gas. The signal transmitted by the lambda
probe is use by the injection and ignition
electronic control unit to adjust the air-fuel
mixture.
Anti-evaporation system
As it is impossible, even when the engine
is switched off, to prevent the formation of
fuel vapours, a system has been devised
which imprisons the vapours in a special ac-
tivated carbon container.
During operation of the engine, these
vapours are sucked up and sent to com-
bustion.
EMISSION REDUCING DEVICES
(JTD engines )Oxidising catalytic converter
Converts the polluting substances present
in the exhaust gases (carbon monoxide, un-
burned hydrocarbons and particulate) into
harmless substances, thus reducing the
fumes and smell that are typical of diesel
engines.
The catalytic converter consists of a stain-
less steel case that houses a ceramic hon-
eycomb body coated with noble metal used
as a catalyst.
Exhaust gas recirculation system
(E.G.R.)
This system recycles, i.e. re-uses, a vary-
ing percentage of the exhaust gases, de-
pending on engine operating conditions.
It is used, when necessary, to control ni-
tric oxides.
Due to the high tempera-
tures reached during oper-
ation of the catalytic converter, the
vehicle should not be parked over
inflammable materials (paper, fuel
oils, grass, dry leaves, etc.).
WARNING

IN AN EMERGENCY
239
69
69
69
69
71
71
69
71
69
69
69
69
72
69
69
69
69
69
69
71 10
11
13
5
4
5
3
7
15
13
15
9
1
4
12
2
15
12
12
10
SERVICES FUSE AMPERES FIGUREWindscreen wiper, windscreen washer/Rearscreen wiper/Rain sensor (optional)HornsGSM Box for Connect/Navigator-electronic warning systemFront power windowsLeft rear power windowRight rear power windowDoor locking system - Boot lightBoot electric openingRearscreen heatingWing mirror adjustmentWing mirror defrostingCigar lighter/Odour sensorHeadlamp washerHeadlamp aiming deviceInstrument clusterMain-beam headlamp warning lightRearscreen heating warning lightSound system/Diagnosis socketElectronic alarm system Supplementary electrical socket in the boot (Sportwagon versions)20A
20A
10A
30A
20A
20A
20A
30A
30A
10A
30A
15A
20A
10A
10A
10A
30A
10A
10A
20A

CAR MAINTENANCE
265
DIESEL FILTERDRAINING CONDENSATION
WATER
Water in the supply circuit
can seriously damage the
whole injection system and
cause malfunctions to engine oper-
ation. Should the warning lamp
c
turn on, available for the provid-
ed versions/markets, contact as
soon as possible the Alfa Romeo
Authorised Service for drainage op-
erations.
When the car is habitual-
ly driven in dusty areas,
the cleaner should be
changed at shorter intervals than
those given in the Programmed
Maintenance Schedule.Any attempt to clean the
air cleaner may cause se-
rious engine damage.
AIR FILTERThe air cleaner is connected to the tem-
perature and air flow sensors which send the
electrical signals needed for correct opera-
tion of the injection and ignition system to
the control unit.
It must therefore always be in perfect con-
ditions to ensure correct operation of the en-
gine, low consumption and exhaust emis-
sion levels.
If they are not carried out
correctly and with the due
precautions, the operations
involving cleaner replacement de-
scribed herein may compromise the
safety of the car.
This operation should be carried
out by Alfa Romeo Authorized Ser-
vices.

ALFA 156 SPORTWAGON
282
LUGGAGE
COMPARTMENTThe boot lid can be opened from outside
the vehicle (pressing the button on the key)
and from inside the vehicle.
WARNINGIf the tailgate is not shut
properly, this will be shown by the corre-
sponding warning light
´
and warning mes-
sage on the Infocenter display.
OPENING FROM INSIDE (fig. 13)
To open the tailgate from inside the pas-
senger compartment pull the lever (A) at
the side of the driver’s seat.fig. 13
A0B0042m
Lifting the tailgate is facilitated by the ac-
tion of the gas springs.
The gas springs are cali-
brated to ensure correct
lifting of the tailgate with
the weights foreseen by the man-
ufacturer. The addition of objects
(spoiler, etc.) may adversely affect
correct operation and safety in use
of the tailgate.
OPENING WITH REMOTE
CONTROL
(fig. 14)
The boot can be opened by remote control
pressing the button (C) on the key, also
when the electronic alarm (where fitted) is
engaged.
In this case the alarm system switches off
volumetric protection and the tailgate con-
trol sensor. The system also sounds two
beeps and the direction indicators light up
for three seconds (with the exception of ver-
sions for certain markets).
Closing the boot again the control functions
are restored, the system sounds two beeps
and the direction indicators light up for three
seconds (with the exception of versions for
certain markets).
fig. 14
A0B9000m
Only use the tailgate open-
ing lever with the car sta-
tionary.
WARNING

TECHNICAL SPECIFICATIONS
305
SPARK PLUGClean, intact spark plugs are determinant
with regard to engine efficiency and for re-
ducing the emission of pollutants.Spark plugs should be re-
placed at the intervals
specified in the Scheduled
Maintenance Programme. Only use
spark plugs of the specified type: if
the thermal capacity is inadequate
or if the envisaged life is not guar-
anteed inconveniences may ensue.BRAKESService brakes:
– front
– rearParking brake
If examined by an expert eye, the ap-
pearance of a spark plug is a sound clue
for locating a fault, even if not involving the
ignition system. Therefore if you are expe-
riencing any engine problems, it is impor-
tant to have the spark plugs checked by Al-
fa Romeo Authorized Services.
STEERING
1.6 T.SPARK 1.8 T.SPARK 2.0 JTS 2.0 JTS 2.5 V6 24V 2.5 V6 24V JTD JTD 20V
Selespeed Q-System JTD 16V Multijet
MultijetSelf-ventilated Self-ventilated Self-ventilated Self-ventilated Self-ventilated Self-ventilated Self-ventilated Self-ventilated
disk disk disk disk disk disk disk disk
Disk Disk Disk Disk Disk Disk Disk Disk
Wheel anti-look system (ABS) with electronic braking distribution.
Servo-brake. Electronic control with brake pad wear sensors. Gasket of ecological type.
Controlled by hand lever operating rear brakes.
Type Turning radius(between pavements)
1.6 T.SPARK 1.8 T.SPARK 2.0 JTS 2.0 JTS 2.5 V6 24V 2.5 V6 24V JTD-JTD 16V JTD 20V
Selespeed Q-System Multijet Multijet
Rack and pinion.
Hydraulic power steering with liquid reservoir in engine compartment
11.1 m 11.1 m 11.1 m 11.1 m 11.6 m 11.6 m 11.1 m 11.1

ALPHABETICAL INDEX
331
N
umber plate lights
– changing bulbs ................ 229-296
O
ddment recesses
– in the boot ........................... 285
– on centre console ................... 165
– on dashboard ........................ 165
Odometer ................................... 59
Paintwork (maintenance) ............ 275
– colour label ........................... 301
Parking....................................... 191
Parking sensors............................ 187
Partial odometer .......................... 63
Performance................................ 314
Pockets and compartments
on front doors ........................... 165
Pollen filter ................................ 266
Power steering
– checking fluid level
and topping up ..................... 262
Power windows ........................... 27
Pre-tensioning devices ................... 32
Protecting emission reducing
devices ....................................... 198
Q
-system automatic gearbox........ 152
– acoustic warning .................... 159
– automatic operation ............... 154
– checking the oil level .............. 260
– fault signalling ....................... 158
– manual operating mode/
Q-System activation................ 157
– moving off ............................ 152
– push starting ......................... 159
– selecting automatic/
manual gearshifting................ 153
– selecting the driving modes ..... 156
– starting the engine ................. 152
– stopping the car ..................... 157
– towing the car ....................... 160
R
adio transmitters and cellular
telephones ............................... 167
Rain sensor ................................. 51
Rear fog guards
– changing bulbs ............... 227-294
– switching on.......................... 136
Rear light units
– bulb replacement ................... 227
Rear roof lights ............................ 163
– changing bulbs ...................... 231
Rear seats................................... 23– centre armrest ................. 23-280
– headrests ....................... 24-279
– ski compartment.............. 24-280
Rear suspensions
(automatic geometry control) ..... 293
Rearscreen heating................. 26-133
Rearscreen washer ....................... 281
– spray jet ............................... 281
Rearscreen wiper
– blade replacement ................. 281
– operation .............................. 281
Reducing running costs
and environment pollution .......... 197
Refilling ..................................... 319
Remote control ............................ 7-12
– additional remote controls ...... 12
– alarm system ........................ 11
– boot opening ......................... 8
– changing the battery .............. 10
– door opening-closing ............... 7
– ministerial homologation ......... 325
– remote door locking/
unlocking .............................. 16
Rev counter................................. 62
Reversing lights
– changing bulbs ................ 227-294