Workshop Manuals Factory service & repair Alfa Romeo
01 General information02 Specifications03 Manufacturing data and tolerances04 Tightening torques05 Fluids and lubricants06 Maintenance07 Diagnostic checks08 Engine09 Clutch10 Gearbox and differential11 Axles and driveshafts12 Brakes13 Steering14 Suspension and wheels15 Heating, air conditioning and auxiliary units16 Electrical equipment17 Body fittings18 Body panels and frame19 Wiring diagrams and electrical functions20 Wiring harnesses21 Connectors and pin-outs22 Fault diagnosis23 Special tools
Alfa Romeo GT Factory Service Manual (2003-2010)19 · Wiring diagrams and electrical functions
19 · Electrical

Radio - functional description

Make
Alfa Romeo
Model
GT Factory Service Manual
Year
2003–2010
Section
Radio accessories › Radio - functional description
Wiring diagrams and electrical functionsRadio - functional description

RADIO - FUNCTIONAL DESCRIPTION

BOSE System

Functional description

The radio P20

receives a direct power supply (7 of connector A) from the battery via the line for fuse F39 of the junction unit under the dashboard B2

and maxifuse CPL of B99

( of B5

for the 3.2 V6 version).

Another specific power supply reaches pin 2 of connector A, to signal the presence of the Bose HIFI system.

The power supply reaches pin 4 of connector A with the side lights on

See E2530 INSTRUMENT LIGHTING

The CAN line arrives at pins 1 and 3 of connector A with which the radio P20

is connected to the Body Computer M1

and to the other system nodes.

Pin 8 of connector A is earthed.

The aerial P25 receives a power supply from pin 5 of connector A

. The aerial is connected to the radio by means of the special coaxial cable.

The cables with signals for the speakers leave from connector B; these signals are sent to the BOSE amplifier P70 which controls the actual speakers.

  • pins 5 and 6 of P20 and pins 31 and 32 of P70 to the left front speakers P35 and P45,
  • pins 3 and 4 of P20 and pins 26 and 27 of P70 to the right front speakers P36 and P46,
  • pins 7 and 8 of P20 and pins 4 and 16 of P70 to the left rear speakers P30 and P47,
  • pins 1 and 2 of P20 and pins 5 and 17 of P70 to the right rear speakers P31 and P48,

The connecting cable leaves connector C of P20 (pins 13-20) for the CD player P75 in accordance with the following connections: - Pin 13 asci bus from CDC to the radio - Pin 14 asci bus from the radio to the CDC - Pin 15 +12 permanent - Pin 16 +12V switched - Pin 17 digital earth - Pin 18 audio earth - Pin 19 left audio CDC - Pin 20 right audio CDC

Pins 10 and 11 of connector C are connected to the radio controls on the steering wheel: the connection takes place via the clock spring D47

; the device which controls the control buttons receives an ignition-operated supply (INT) from the line protected by fuse F51 of the junction unit under the dashboard B2

, whilst the reference earth arrives from pin 12 of connector C of P20

The amplifier P70

receives a direct supply from the battery - at pin 1 - via the line for fuse F2 of B1 and the specific fuse F61 in the additional fuse box B98

Pin 6 is then connected with a special line to the radio P20

pin 6 of connector C which sends the on signal for the actual amplifier.

Pin 2 of P70

is earthed.

The other signals leaving the BOSE amplifier P70

control the "basic" system speakers as described previously. In addition, signals leave pins 3-15 and 11-12 which control the rear subwoofer P49

At pins 29 and 30 of P70

the signals from the ambient microphone P02 arrive

All versions

Operational description

The radio P20

receives a direct power supply (7 of connector A) from the battery via the line for fuse F39 of the junction unit under the dashboard B2

and maxifuse CPL of B99

The power supply reaches pin 4 of connector A with the side lights on

See E2530 INSTRUMENT LIGHTING

The CAN line arrives at pins 1 and 3 of connector A with which the radio P20

is connected to the Body Computer M1

and to the other system nodes.

Pin 8 of connector A is earthed.

The aerial P25 receives a power supply from pin 5 of connector A

. The aerial is connected to the radio by means of the special coaxial cable.

The following cables with signals for the speakers leave connector B:

  • pins 5 and 6 to the left front speakers P35 and P45,
  • pins 3 and 4 to the right front speakers P36 and P46,
  • pins 7 and 8 to the left rear speakers P30 and P47,
  • pins 1 and 2 to the right rear speakers P31 and P48,

Pins 10 and 11 of connector C are connected to the radio controls on the steering wheel: the connection takes place via the clock spring D47

; the device which controls the control buttons receives an ignition-operated supply (INT) from the line protected by fuse F51 of the junction unit under the dashboard B2

, whilst the reference earth arrives from pin 12 of connector C of P20

The connecting cable leaves connector C of P20 (pins 13-20) for the CD player P75 in accordance with the following connections: - Pin 13 asci bus from CDC to the radio - Pin 14 asci bus from the radio to the CDC - Pin 15 +12 permanent - Pin 16 +12V switched - Pin 17 digital earth - Pin 18 audio earth - Pin 19 left audio CDC - Pin 20 right audio CDC

BOSE System, Right hand drive

Operational description

The radio P20

receives a direct power supply (7 of connector A) from the battery via the line for fuse F39 of the junction unit under the dashboard B2

and maxifuse CPL of B99

( of B5

for the 3.2 V6 version).

Another specific power supply reaches pin 2 of connector A, to signal the presence of the Bose HIFI system.

The power supply reaches pin 4 of connector A with the side lights on

See E2530 INSTRUMENT LIGHTING

The CAN line arrives at pins 1 and 3 of connector A with which the radio P20

is connected to the Body Computer M1

and to the other system nodes.

Pin 8 of connector A is earthed.

The aerial P25 receives a power supply from pin 5 of connector A

. The aerial is connected to the radio by means of the special coaxial cable.

The cables with signals for the speakers leave from connector B; these signals are sent to the BOSE amplifier P70 which controls the actual speakers.

  • pins 5 and 6 of P20 and pins 31 and 32 of P70 to the left front speakers P35 and P45,
  • pins 3 and 4 of P20 and pins 26 and 27 of P70 to the right front speakers P36 and P46,
  • pins 7 and 8 of P20 and pins 4 and 16 of P70 to the left rear speakers P30 and P47,
  • pins 1 and 2 of P20 and pins 5 and 17 of P70 to the right rear speakers P31 and P48,

The connecting cable leaves connector C of P20 (pins 13-20) for the CD player P75 in accordance with the following connections: - Pin 13 asci bus from CDC to the radio - Pin 14 asci bus from the radio to the CDC - Pin 15 +12 permanent - Pin 16 +12V switched - Pin 17 digital earth - Pin 18 audio earth - Pin 19 left audio CDC - Pin 20 right audio CDC

Pins 10 and 11 of connector C are connected to the radio controls on the steering wheel: the connection takes place via the clock spring D47

; the device which controls the control buttons receives an ignition-operated supply (INT) from the line protected by fuse F51 of the junction unit under the dashboard B2

, whilst the reference earth arrives from pin 12 of connector C of P20

The amplifier P70

receives a direct supply from the battery - at pin 1 - via the line for fuse F2 of B1 and the specific fuse F61 in the additional fuse box B98

Pin 6 is then connected with a special line to the radio P20

pin 6 of connector C which sends the on signal for the actual amplifier.

1.9 JTD 16V · BOSE System, Right hand drive

Pin 2 of P70

BOSE System, Right hand drive

is earthed.

The other signals leaving the BOSE amplifier P70

control the "basic" system speakers as described previously. In addition, signals leave pins 3-15 and 11-12 which control the rear subwoofer P49

At pins 29 and 30 of P70

the signals from the ambient microphone P02 arrive

Parts & tools for this job Staging For 2003 Alfa Romeo GT

Links open Amazon search results in a new tab. As an Amazon Associate I earn from qualifying purchases.