All values measured to ground unless otherwise noted
Conn./Plug/Pin Pin Information Test Value Comments
A2      
A.1 VSS signal input 0-2 VAC, 0-300 Hz with increasing vehicle speed
Radio on:
Output volume increasing step-by-step		 Feed from traction system ECM
A.2 "Diagnostic port" for DTC readout and diagnostic purpose No reliable test. Check continuity of wiring  
A.3 CTEL mute ground signal input Radio on, activate CTEL function:
Radio switches to mute and display shows PHONE		 Refer to wiring diagrams 82.70
A.4 Circuit 30 power input 12 VDC at all times Feed from F1f10
A.5 Control voltage output for antenna and sound system amplifier 12 VDC with radio on  
A.6 Circuit 58d input, "Dimmed Instrument Illumination" voltage Varies from 0.5-12 VDC, depending on setting of dimming value
Parking lights on: Radio buttons illuminated
Radio on: Radio buttons and display illuminated		 Feed from IC via Z81/4
A.7 Circuit 15R power input Ignition on 12 VDC Feed from F1f3
A.8 Main ground to W19 Approx. 0 Ohms to ground  
B.1
B.2		 Right rear audio signal plus output
Right rear audio signal minus output		 Radio on > 0.2 VAC across pin B.1-B.2 Note 1
B.3
B.4		 Right front audio signal plus output
Right front audio signal minus output		 Radio on > 0.2 VAC across pin B.3-B.4 Note 1
B.5
B.6		 Left front audio signal plus output
Left front audio signal minus output		 Radio on > 0.2 VAC across pin B.5-B.6 Note 1
B.7
B.8		 Left rear audio signal plus output
Left rear audio signal minus output		 Radio on > 0.2 VAC across pin B.7-B.8 Note 1
C.1-3 Pins not used    
C.4
 Wake up output for other ECM's Radio on approx. 10-14 VDC

 Refer to D. M. Info./Comm.
Vol. 1, 6.1
C.5-7 Pins not used    
C.8-10 Ground to W6 Approx. 0 Ohms to ground or 12 VDC to pin A.4 Used for coding:
With/without sound-system, 2-/4- channel speaker system
D Antenna input connector Radio frequency  
D2B IN
D2B OUT		 Optical input port
Optical output port		 No reliable test  
N40/3      
1
2		 Right front audio signal minus input
Right front audio signal plus input		 Radio on > 0.2 VAC across pin 1-2 and volume to max.  
3 Left rear audio signal minus input Radio on > 0.2 VAC across pin 3-5 and volume to max.  
4 Right rear audio signal minus input Radio on > 0.2 VAC across pin 4-6 and volume to max.  
5 Left rear audio signal plus input See pin 3  
6 Right rear audio signal plus input See pin 4  
7 Pin not used    
8 Control voltage input for antenna and sound/ system amplifiers 12 VDC with radio on  
9 Ground to W6 Approx. 0 Ohms to ground  
10 Left front audio signal minus input Radio on > 0.2 VAC across pin 10-18 and volume to max.  
11 Right rear speaker (sedan) or bass module 1 output Radio off, measure across pins 11-19:
1.5-2.5 Ohms (sedan)
0.5-1.5 Ohms (wagon)		 Note 1
12 Left rear speaker (sedan) or bass module 2 output Radio off, measure across pins 12-20:
1.5-2.5 Ohms (sedan)
0.5-1.5 Ohms (wagon)		 Note 1
13 Left front speaker output 1.5-2.5 Ohms across pins 13-21 with radio off Note 1
14 Right front speaker output 1.5-2.5 Ohms across pins 14-22 with radio off Note 1
15 Left rear door speaker output 1.5-2.5 Ohms across pins 15-23 with radio off Note 1
16 Pin not used    
17 Right rear door speaker output 1.5-2.5 Ohms across pins 17-25 with radio off Note 1
18 Left front audio signal plus input See pin 10  
19 Right rear speaker (sedan) or bass module 1 output See pin 11  
20 Left rear speaker (sedan) or bass module 2 output See pin 12  
21 Left front speaker output See pin 13  
22 Right front speaker output See pin 14  
23 Left rear door speaker output See pin 15  
24 Pin not used    
25 Right rear door speaker output See pin 17  
26 Circuit 30 power input 12 VDC all times Feed from F1f12
Note 1 Substitution test for speaker sytems
Use signal generator		 Disconnect appropriate speaker and connect to a low frequency signal generator.
Adjust output to approx. 2.5 Vpp and vary frequency over a range from 10 Hz to 15 kHz. Sound should be audible over most of the range, depending of speaker system under test (bass/tweeter)