Alfa Romeo 156 2.4 JTD 20v da 04/98 a 02/99 – PARKING SENSOR – – WIRING DIAGRAM, LOCATION COMPONENTS, OPERATIONAL DESCRIPTION – WIRING DIAGRAM, LOCATION COMPONENTS, OPERATIONAL DESCRIPTION

Wiring diagram

Get access to all wiring diagrams of the car

Components

Component code	Name	Assembly reference
D20	/Rear dashboard coupling	-
D70	Left seat connection	-
D89	Rear.-rear bumper coupling	-
K97	parking sensor	-
M84	Parking control unit	-
P44	Rear buzzer for parking sensors	-

Location of components

Get access to all wiring diagrams of the car

Components

Component code	Name	Assembly reference
D20	/Rear dashboard coupling	-
D70	Left seat connection	-
D89	Rear.-rear bumper coupling	-
K97	parking sensor	-
M84	Parking control unit	-
P44	Rear buzzer for parking sensors	-

DescriptionThe parking assistance system provides the driver with informationwhilst reversing relating to distance when approaching obstacleswhich are behind the vehicle, which could be outside the driver'sfield of view.The information that there is an obstacleand its distance is transmitted to the driver by means of acousticsignals whose frequency varies according to the distance of thevehicle from the obstacle.An electronic control unit activates andcontrols the operation of the four sensors located in the rear bumper,processing the signals received and activating the acoustic signalinside the luggage compartment on the left hand side.The system is activated when reverse gearis engaged: under these conditions the control unit energizes thetransducers and sends them a request signal, receiving responsesignals.The ultrasound technology sensors act asintelligent transmitters/receivers through a triangulation technique:this allows improved detection in critical situations or in thepresence of small obstacles. The impulses emitted are reflectedby any obstacles; the transducer therefore receives an echo whichis converted into a digital signal and sent to the electronic controlunit.The distance of the obstacle is signalledby sounds with intermittent impulses: the frequency of this signalincreases gradually as the bumper approaches an obstacle: when thedistance calculated is less than about 30 cm, the sound becomeshigh pitched and constant; the acoustic signal, on the other hand, ceaseswhen the distance of the obstacle increases. For more details and information on theoperation of the system, 3232974Characteristic of working principle5580Hparking obstacle detectiondeviceThe control unit has an autodiagnostic function:when it is switched on the control unit carries out an initial teston the sensors.which are then continuously diagnosed during theoperation of the system.A fault with only one sensor inhibits theoperation of the entire system: in this case, the system excludesitself: the failure status is signalled sending a suitable highfrequency acoustic warning. The system is activated with reverse gearengaged; the signal that the reversing light 3233866SeeE2022REVERSING LIGHTS hascome on supplies the parking sensors control unit directly.

Functional description The parking sensor control unit M84 is supplied at pin 1 ofconnector A by the ignition-operated line INT protected by fuseF1 of junction unit B1 with this line sending the power supply tothe control unit M84 with reverse gear engaged (switch I20) thissupply is also sent from pin 6 to pin 9 of connector A of M84; pins16 of connector A of M84 is earthed. The control signals for activating the buzzer P44 are sent from pins 2 and 10 of connector A of M84. The four parking sensors K97 are connectedto connector B of control unit M84; pin 1 provides the referenceearth, pin 6 the power supply to the sensors; pin 4 suppliesthe signal to the right outer sensor K97D, pin 2 to the rightinner sensor K97C, pin 3 to the right inner sensor K97B and pin5 to the left outer sensor K97.