2007 Alfa Romeo 166 sensor

The heart of the VDC system is a sensor
that originates from the field of aeronau-
tics, which detects rotations of the car
around its vertical axis. The centrifugal
forces generated when the car runs on a
bend 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 accelera-
tion and individual wheel rotation sen-
sors. These signals allow the control unit
to recognise the manoeuvre the driver in-
tends to do when turning the steering
wheel.
118
VDC SYSTEM OPERATION
The 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 sys-
tem are:
– an electronic control unit which
processes the signals received from the
various sensors and brings about the
most appropriate 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 accelera-
tion (centrifugal force).The control unit processes the informa-
tion received from the sensors and is
therefore capable of detecting the posi-
tion of the car and comparing it with the
trajectory the driver would like to follow
instant by instant. In the event of a dis-
crepancy, the control unit chooses and
commands the most suitable action to
bring the car back to the required 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
controlled continuously until the car re-
turns to the required course.
The action of the VDC system consider-
ably increases the active safety of the ve-
hicle under many critical situations and it
is particularly useful also when the road
surface grip conditions change.

130
Lambda sensors
The lambda sensors detect the oxygen
content in the exhaust gas.
The signals transmitted by the Lambda
sensors are used by the electronic control
unit of the injection-ignition system to ad-
just the air-fuel mixture.Anti-evaporation system
(only petrol versions)
As it is impossible, even when the en-
gine is switched off, to prevent the forma-
tion of fuel vapours, a system has been
devised which traps them in a special car-
bon container.
During operation of the engine these
vapours are withdrawn and sent to com-
bustion.
Due to the high temper-
ature reached while the
catalysts are working, it is advis-
able not to park the car over in-
flammable material (paper, fuel
oils, grass, dry leaves, etc.).
WARNING

141
greatly reduced when there is ice or snow
on the road. Under these conditions the
stopping distance is increased despite the
use of the ABS system.VDC SYSTEM (VEHICLE
DYNAMICS CONTROL):
The VDC is an electronic vehicle stability
control system which, acting on the torque
and braking the wheels in a differentiated
manner, helps to bring the car back to the
correct course in the event of loss of grip.
When the sensors detect the conditions
that would lead to skidding, the VDC sys-
tem intervenes on the engine and on the
brakes producing a stabilising torque.
BRAKE ASSIST (Brake assist in
an emergency)
This system, that cannot be cut out, rec-
ognizes emergency braking on the
ground of the brake pedal operation
speed and allows to speed up the braking
action.
On versions fitted with VDC system, Brake
Assist is deactivated in the event of VDC
system failure (indicated by the switching
on of the relevant warning light).
The ABS system does not
dispense the driver from
driving carefully, especially when
the road is icy, snowed over or
wet.
WARNING
The car is fitted with an
electronic braking device
(EBD). if the
>andxwarning
lights turn on at the same time, this
means that there is an EBD system
fault; in this case violent braking
may be accompanied by early rear
wheel locking, with the possibility
of skidding. Drive the car extremely
carefully to the nearest Authorized
Alfa Romeo workshop to have the
system checked.
WARNING
The turning on of only
the
>warning light
with the engine running normally
indicates a fault to the ABS system
only. In this case the braking sys-
tem is still efficient, though with-
out the aid of the anti-lock device.
Under these conditions perfor-
mance of the EBD system may be
reduced. In this case too, you are
advised to go immediately to the
nearest Authorized Alfa Romeo
workshop, driving in such a way
as to avoid sharp braking, to have
the system checked over.
WARNING
The system performance
levels, in terms of active
safety, should not induce the dri-
ver to run pointless and unjustified
risks. Driving conduct should al-
ways be suited to the conditions of
the road surface, vision and traf-
fic. The responsibility for road
safety is always and anyway the
vehicle driver’s concern.
WARNING

151
Use an auxiliary battery to start the ve-
hicle in an emergency.
If the engine is not “running smoothly”
when the vehicle is travelling, reduce the
request for performance to a minimum
and contact Alfa Romeo Authorized Ser-
vices as soon as possible.
When the fuel reserve warning light
comes on fill up as soon as possible. A
low fuel level may cause an irregular sup-
ply to the engine with inevitable increase
of the exhaust gas temperature.
When travelling downhill for long
stretches slightly rev the engine every
now and again. This action will extend
the life of the catalyzer.
Never run the engine, even as a test,
with one or more spark plugs disconnect-
ed.
During normal operation
the catalytic converter
reaches high temperatures. Do not
therefore park the vehicle over in-
flammable materials (grass, dry
leaves, pine needles etc.): fire haz-
ard. Do not install other heat
shields and do not remove the ex-
isting ones on the catalyst and on
the exhaust pipe.
Do not spray anything on the cat-
alyst, lambda sensor and exhaust
pipe.
WARNING
The failure to follow
these rules may cause a
fire hazard.
WARNING

190
FUSES AND RELAYS IN THE
BOOT
Fuses and relays are housed in the
right-hand side of the boot are housed in
a box, in the recess closed by cover (A-
fig. 92).
To open the cover turn the knob (B).
The devices protected by the fuses in
the boot are listed in the tables on next
pages.IMPORTANTThe arrangement of the
relays may vary depending on the ver-
sions and markets. In the event of a sus-
pected anomaly, contact Alfa Romeo Au-
thorized Services.Circuits operated by relays are the fol-
lowing (fig. 93):
A.Air mixing actuator, climate control
unit, additional heater control (JTD ver-
sions)
B.Rearscreen heating relay
C.Seat warming control, elec-
trochromic driving mirror, sun visor light,
rain sensor, parking sensor control unit,
door mirror control light, remote control
receiver, alarm system control unit, dri-
ver's power window control LOCK warn-
ing light
D.Windscreen heating, door mirror de-
frosting
E.Front seat warming, rear current
socket, front seat electric adjustment,
powered sunroof
F.Direction indicators, trailer presetting
518PGS
fig. 93
A0D0097m
A0D0111m
fig. 92

191
System/Component Fuse no. Ampere Location
ABI control unit 13 10A fig. 86
ABI control unit – Central locking 19 20A fig. 93
ABI control unit – Front LH power window 18 20Afig. 93
ABI control unit – Front RH power window 3 20A fig. 93
ABI control unit – Rear LH power window 14 20Afig. 93
ABI control unit – Rear RH power window 17 20Afig. 93
ABS control unit 9 5A fig. 86
7 40A fig. 89
3 40A fig. 89
Additional heater (JTD versions) 17 20A fig. 89
13 10A fig. 93
Alarm system (control unit) 12 10A fig. 93
15 10A fig. 93
Alfa Romeo Code System 20 5A fig. 86
16 5A fig. 86
Cell phone (handset) 18 5A fig. 86
5 10A fig. 86
Central locking (ABI control unit) 19 20A fig. 93
Cigar lighter 7 20A fig. 86
Climate control fan 2 30A fig. 89
Climate control unit 19 5A fig. 86
External lights Fuse no. Ampere Location
Brake lights (switch) 9 5A fig. 861 15A fig. 86
Direction indicators 12 10A fig. 93
External lights (control) 5 10A fig. 86
Front fog lights 16 15A fig. 89
Headlights and headlight position
sensor (gas discharge headlights) 6 7.5A fig. 86
IGE control unit:
- brake light switch 1 15A fig. 86
- brake lights 9 5A fig. 86
- headlight spot 11 15A fig. 86
- left side lights 17 10A fig. 86
- rear light units 15 10A fig. 86
- right side lights 8 10A fig. 86
Left dipped beam headlight 12 15A fig. 89
Reversing lights (only versions with
manual gearbox) 13 10A fig. 86
Right dipped beam headlight 10 15A fig. 89
Internal lights Fuse no. Ampere Location
Dashboard light dimmer 5 10A fig. 86
Door mirror control light 15 10A fig. 93
Glovebox light 5 10A fig. 86
Seat warming control light 15 10A fig. 93
Sun visor lights 15 10A fig. 93

193
System/Component Fuse no. Ampere Location
Rearscreen heating 1 30A fig. 93
Relay coil T21, T22, T23 (boot box) 3 5A fig. 86
Relay coil T24 (boot box) 5 10A fig. 86
Remote control receiver 15 10A fig. 93
Sound amplifier 20 25A fig. 93
Sound system 4 15A fig. 86
Sound system controls on steering wheel 5 10Afig. 86
Starter motor 1 30A fig. 89
Trailer presetting 12 10A fig. 93
Windscreen heating 7 15A fig. 93
Windscreen wiper 14 25A fig. 86
System/Component Fuse no. Ampere Location
Navigator 18 5A fig. 86
Parking sensors (control unit) 15 10A fig. 93
Power windows (driver's control
LOCK warning light) 15 10A fig. 93
Powered sunroof 10 20A fig. 93
Presetting 4 – fig. 93
11 – fig. 93
Rain sensor 15 10A fig. 93
Rear current socket 16 20A fig. 93
Rear LH power window (ABI control unit) 14 20Afig. 93
Rear RH power window (ABI control unit) 17 20Afig. 93

218
Any attempt to clean
the air cleaner may
cause serious engine
damage.
If they are not carried
out correctly and with
the due precautions, the
operations involving cleaner re-
placement described herein may
compromise the safety of the
car. This operation should be car-
ried out by Alfa Romeo Autho-
rized Services.
AIR CLEANER
The air cleaner is connected to the tem-
perature and air flow sensors which send
the electrical signals needed for correct
operation of the injection and ignition sys-
tem to the control unit.
It must therefore always be in perfect
conditions to ensure correct operation of
the engine, low consumption and exhaust
emission levels.When the car is habitu-
ally driven in dusty ar-
eas, the cleaner should
be changed at shorter intervals
than those given in the Pro-
grammed Maintenance Schedule.
IMPORTANT When topping up use
the special detergents available in the
shops ensuring that they contain antis-
cale and antifreeze properties.
If in doubt contact Alfa Romeo Autho-
rized Services who will be able to recom-
mend the most suitable products.
Do not travel with the
windscreen washer
reservoir empty: the action of the
windscreen washer is fundamental
for improving vision.
WARNING