All values measured to ground unless otherwise noted
Conn./Plug/Pin	Pin Information	Test Value	Comments
N47-7
1.1	Pin not used
1.2	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
1.3	Pin not used
1.4	Stop lamp switch (normally closed) input	Ignition on, 12 VDC with brakes not applied, 0 VDC with brakes applied.
1.5	Pin not used
1.6	Parking brake switch ground signal input	Approx. 0 Ohms to ground with parking brake pedal depressed
1.7,8	Pins not used
1.9	"Diagnostic port" for DTC readout and diagnostic purpose	Ignition on 12 VDC	To be tested with HHT refer to D.M.
1.10	Circuit 15 switched power input, switched by relay K40k1	Ignition on 12 VDC
1.11	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
1.12 1.13	Rear axle VSS sensor, + input. Rear axle VSS sensor, - input.	ECM disconnected 0.6-1.8 kOhms across pins 1.12 and 1.13 Sine wave. Frequency varies with wheel speed.	Note 1
1.14-30	Pins not used
2.1-16	Pins not used
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.
2.22	Pins not used
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	Pin not used
2.25	Return pump relay activated monitoring signal input and pump voltage supply	12 VDC to pin 2.27 with relay activated
2.26 2.27	Return pump relay common output activation signal output	12 VDC to pin 2.26 with relay activated	Coil resistance approx. 40-80 Ohms
2.28-34	Pins not used
ABS Bosch
2.35	Rear axle hold valve signal, switched ground activates solenoid valve A7/3y20	12 VDC with valve energized 0 VDC with valve not energized ECM disconnected 5.4-12.6 Ohms to ground
2.36	Rear axle release valve signal, switched ground activates solenoid valve A7/3y21	12 VDC with valve energized 0 VDC with valve not energized ECM disconnected 2.8-6.6 Ohms to ground
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 ground
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 ground
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 ground
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 ground
2.46	Hydraulic unit solenoid valve power input	Ignition on 12 VDC
ABS Teves
2.21	Hydraulic unit solenoid valve power input	Ignition on 12 VDC
2.35	Rear 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 ground
2.36	Rear axle release valve signal, switched ground activates solenoid valve A7/3y6	12 VDC with valve energized 0 VDC with valve not energized ECM disconnected 2.8-6.6 Ohms to ground
2.38	Left front axle release valve signal, switched ground activates solenoid valve A7/3y20	12 VDC with valve energized 0 VDC with valve not energized ECM disconnected 2.8-6.6 Ohms to ground
2.39	Left front axle hold valve signal, switched ground activates solenoid valve A7/3y21	12 VDC with valve energized 0 VDC with valve not energized ECM disconnected 5.4-12.6 Ohms to ground
2.40	Right front axle hold valve signal, switched ground activates solenoid valve A7/3y9	12 VDC with valve energized 0 VDC with valve not energized ECM disconnected 5.4-12.6 Ohms to ground
2.46	Right 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 ground
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	Pin not used
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
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.