All values measured to ground unless otherwise noted
Conn./Plug/Pin Pin Information Test Value Comments
N47-5      
1.1 LF VSS output, generated by L6/1, processed in ECM and sent to other ECMs Ignition on, lift front of vehicle.
Turn left front wheel > 1 rev/sec by hand > 3 VAC or with vehicle moving		 20 mph / 200 Hz
35 mph / 330 Hz
square wave
1.2 RF VSS output, generated by L6/2, processed in ECM and sent to other ECMs Ignition on, lift front of vehicle.
Turn right front wheel > 1 rev/sec by hand > 3 VAC or with vehicle moving		 20 mph / 200 Hz
35 mph / 330 Hz
square wave
1.3-6 Pin not used    
1.7 ESP OFF/ON recognition voltage coded signal input Ignition on 5 VDC.
ESP switch held in OFF pos: approx. 1-3 VDC
ESP switch held in ON pos: 0 VDC		  
1.8 Parking brake switch ground signal input Approx. 0 Ohms to ground with parking brake pedal depressed  
 
1.9
1.10		 Stop lamp suppression relay
voltage supply output
switched ground activartion signal output		  
Measure to pin 2.23, ignition on 12 VDC		 Coil res. approx.
40-80 Ohms
1.11 Stop lamp switch (normally closed) input Ignition on, 12 VDC with brakes not applied,
0 VDC with brakes applied		  
1.12 Pin not used    
1.13 "Diagnostic port" for DTC readout and diagnostic purpose Ignition on 12 VDC To be tested with
HHT refer to D.M.
1.14 Circuit 15 switched power input, switched by relay K40/4k1 Ignition on 12 VDC  
1.15 Stop lamp switch (normally open) input.
Same signal as to brake lights		 Ignition on, 12 VDC with brakes applied,
0 VDC with brakes not applied		  
1.16 Steering angle sensor signal input Disconnect ECM,
ignition on > 3 VAC		  
 
1.17
1.18		 Yaw rate sensor voltage supply output
low side
high side		  
Ignition on
measure to pin 1.17 12 VDC		  
1.19 Yaw rate sensor signal input
actual driving situation value		 No reliable test To be tested with
HHT refer to D.M.
1.20 Yaw rate sensor reference signal input
quiescent condition value, vehicle not moving		 Ignition on , measure to pin 1.17
static value approx. 2.5 VDC,
move vehicle in lateral direction
dynamic value > 5mVAC		 To be tested with
HHT refer to D.M.
1.21 Test signal output to yaw rate sensor No reliable test To be tested with
HHT refer to D.M.
1.22
 Lateral acceleration sensor voltage supply
output		 Ignition on
measure to pin 1.24 5 VDC		  
1.23 Lateral acceleration sensor signal input Ignition on measure to pin 1.23
move vehicle in lateral direction > 10mVAC		  
1.24 Lateral acceleration sensor voltage supply low side and sensor ground See pin 1.22  
1.25
1.26		 Left rear axle VSS sensor, + input
Left rear axle VSS sensor, - input		 ECM disconnected
0.6-0.6 kOhms across pins 1.25 and 1.26
Sine wave. Frequency varies with wheel speed		 Note 1
1.27
1.28		 Right rear axle VSS sensor, + input
Right rear axle VSS sensor, - input		 ECM disconnected
0.6-1.6 kOhms across pins 1.27 and 1.28
Sine wave. Frequency varies with wheel speed		 Note 1
1.29,30 Pins not used    
2.1,2 Pins not used    
2.3 Membrane travel sensor
voltage supply output low side (ground)		 Ignition on 12 VDC to circuit 30 pin 2.24  
2.4 Membrane travel sensor signal input
detects emergency brake situation and initialises BAS function		 Ignition on
brake not applied < 1 VDC, applied 5 VDC		  
2.5 Membrane travel sensor
voltage supply output high side		 Ignition on 5 VDC  
2.6 Brake release switch voltage supply output Ignition on 12 VDC  
 
2.7
2.8		 Brake release switch
normally open signal
normally closed signal		 Ignition on
brake applied < 1 VDC, not applied 12 VDC
brake not applied < 1 VDC, applied 12 VDC		 Note 2
2.9,10 Pins not used    
2.11 Return pump relay activated monitoring signal input and pump voltage supply 12 VDC to pin 2.12 with relay activated  
 
2.12
2.13		 Return pump relay
common output
activation signal output		  

12 VDC to pin 2.12 with relay activated		 Coil resistance approx. 40-80 Ohms
2.14 Brake pressure sensor voltage supply low side Ignition on, measure to pin 2.16 5 VDC  
2.15 Brake pressure sensor signal input
equivalent to force applied to brake pedal		 Ignition on
depress brake pedal > 2 VDC		  
2.16 Brake pressure sensor voltage supply output See pin 2.14  
2.17
2.18		 Right front axle VSS sensor, + input
Right front axle VSS sensor, - input		 ECM disconnected
0.8-2.3 kOhms across pins 2.17 and 2.18
Sine wave. Frequency varies with wheel speed		 Note 1
2.19
2.20		 Right front brake pad wear recognition, lights
indicator lamp when pads worn down		 ECM disconected:
Open circuit in normal condition.
Short circuit with brake pads worn down		  
2.21 Pin not used    
2.22 BAS solenoid valve activation signal output
activated from sensor A7/7b1 output signal		 Ignition off ECM disconnected
measure to pin 2.5 < 5 Ohms		  
2.23 Main ground to W29/2 Approx. 0 Ohms to ground or
measure to circuit 30 12 VDC		 Same as pin 2.47
2.24 Circuit 30 main power input 12 VDC at all times Same as pin 2.48
2.25 Switchover valve 1 signal output, switched ground activates solenoid valve A7/3y18 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.26 Inlet valve 1 signal output, switched ground activates solenoid valve A7/3y22 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.27 Switchover valve 2 signal output, switched ground activates solenoid valve A7/3y19 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.28 Inlet valve 2 signal output, switched ground activates solenoid valve A7/3y23 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.29 Right rear axle hold valve signal, switched ground activates solenoid valve A7/3y12 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.30 Right rear axle release valve signal, switched ground activates solenoid valve A7/3y13 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 2.8-6.6 Ohms to ground		  
2.31-34 Pins not used    
2.35 Left rear axle hold valve signal, switched ground activates solenoid valve A7/3y10 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.36 Left rear axle release valve signal, switched ground activates solenoid valve A7/3y11 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 2.8-6.6 Ohms to pin 2.46		  
2.37 Right front axle release valve signal, switched ground activates solenoid valve A7/3y9 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 2.8-6.6 Ohms to pin 2.46		  
2.38 Left front axle release valve signal, switched ground activates solenoid valve A7/3y7 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 2.8-6.6 Ohms to pin 2.46		  
2.39 Left front axle hold valve signal, switched ground activates solenoid valve A7/3y6 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.40 Right front axle hold valve signal, switched ground activates solenoid valve A7/3y8 12 VDC with valve energized
0 VDC with valve not energized
ECM disconnected 5.4-12.6 Ohms to pin 2.46		  
2.41
2.42		 Left front brake pad wear recognition, lights
indicator lamp when pads worn down		 ECM disconected:
Open circuit in normal condition.
Short circuit with brake pads worn down		  
2.43
2.44		 Left front axle VSS sensor, - input
Left front axle VSS sensor, + input		 ECM disconnected
0.8-2.3 kOhms across pins 2.43 and 2.44
Sine wave. Frequency varies with wheel speed		 Note 1
2.45 BAS solenoid valve power supply output Ignition on 5 VDC  
2.46 Hydraulic unit solenoid valve power input Ignition on 12 VDC  
2.47 Main ground to W29/2 Approx. 0 Ohms to ground or
measure to circuit 30 12 VDC		 Same as pin 2.23
2.48 Circuit 30 main power input 12 VDC at all times Same as pin 2.24
3.H CAN-Bus (high side). High speed data transfer bus input and output, shares data with other ECMs No reliable test. Check continuity to other ECMs
approx. 5 VAC when data is on bus		 HHT is also used for
CAN diagnosis
3.L CAN-Bus (low side)    
Note 1 To test, spin wheel at 1 rev/sec, measure at least 120 mVAC between both wires of sensor. If voltage is OK, measure the sensor's resistance while pulling, twisting and bending the sensor wires, looking for intermittent opens. Finally, check the sensor tip and rotor teeth for dirt or breakage. An oscilloscope can also be used to check the waveform - chipped or dirty teeth show up as missing or malformed waves.    
Note 2 HHT actual values shows only normally closed signal.
Check normally open signal by observing brake lights