KOEO, remove the connector for each sensor. One of the wires will have a 5 volt reference out signal.
Any of the splices, 73/3077 to 73/5066 will be 5-volt reference signal out and ground wire for sensor.
7/120 and 7/121 are the rear height sensors.
The SUM sends out 5-volts. to the height sensors. Each height sensor is a variable resistor. As the car moves up/down the return voltage will change. This tells the SUM the exact location of each corner of the car.
The 2 PDF’s are for specs and SUM pin in/outs.
CEM-B104421 Rear Axle Sensor. General Signal Failures. Signal too low, could be a shorted to ground or cut wire. The return level height voltage is below spec, see red line.
Sensor 7/120, LH rear,
Pin 1 = SUM C1:23 Ground, Green/Brown wire
Pin 4 = SUM C1:28 Height sensor signal, Violet/White wire
Pin 5 = SUM C1:25 5-volt reference signal, Yellow/Green
There is a SUM calibration. Steering wheel straight, car on flat surface. The SUM needs to know the input of all 4 level sensors to get a known level starting point.
CEM-B104421 Rear Axle Sensor. General Signal Failures. Signal too low
Diagnostic trouble code (DTC) information CEM-B104421
Condition
The central electronic module (CEM) checks the signals from the position sensors.
The diagnostic trouble code (DTC) is stored if the control module detects that:
The signal from the rear position sensor is less than 3 % of the supply voltage.
The control module’s test for the diagnostic trouble code (DTC) starts in the event of:
Voltage supplied sensor.
Vehicles without Four-C.
Note! The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.
Substitute value
Constant light beam length will be used.
Side control freezes straight ahead.
Possible source
Short-circuit to ground in the power supply.
Contact resistance, oxidation or poor contact in connectors or connections.
Short-circuit to ground in the signal cable to the front / rear position sensor.
Open-circuit in the signal cable to the front position sensor.
Open-circuit in the voltage supply lead to position sensor.
Damaged sensor.
Hint:
If both diagnostic trouble codes CEM-B104321 and CEM-B104421 are set at the same time, then check the voltage feed to the sensors for short-circuiting to ground since the lines are internally interconnected in the central electronic module (CEM).
Fault symptom
9T, Headlights/Vertical adjustment not influenced by steering wheel
DC, Headlights/Headlight aim is off
Sensors
1 Fuel level
2 Clutch pedal switch
3 Clutch pedal position sensor
4 Accelerator pedal (AP) position sensor
5 Twilight sensor
6 Sun sensor
7 Diagnostic socket, brake lamp (BDS) (3/284)
8 Brake lamp switch (BLS) (3/9)
9 Front position sensor (from model year 2012)
10 Rear position sensor (from model year 2012)
