Headlight Beam Adjustment System HBA 01
Fault overview
Fault Code 1
Motor circuit, left
This fault is stored in the following cases:
1. Short circuit to ground or open circuit in the circuit between control module and servomotor for HBA, left, terminals 1, 2, 3, 4
2. Servomotor for HBA, left, is faulty
3. The control module is faulty
Elimination:
- Switch off ignition
- Pull plug off the control module
- Pull plug off the servomotor for HBA
- Check for open circuit in the supply leads to the servomotor for HBA, terminals 1, 2, 3, 4
Ohmmeter display < 5 Ohm
- Check for short to B+ in the supply leads to the servomotor for HBA
Ohmmeter connected to terminals 1, 2, 3, and 4; measure resistance to ground
Ohmmeter display Infinity Ohm
- Check for short circuits between the supply leads.
If no fault is detected in the wires, replace the servomotor for HBA. Also check the plug on the wiring harness side and replace if necessary.
Fault Code 2
Motor circuit, right
This fault is stored in the following cases:
1. Short circuit to ground or open circuit in the circuit between control module and servomotor for HBA, right, terminals 5, 6, 7, 8
2. Servomotor for HBA, right, is faulty
3. The control module is faulty
Elimination:
- Switch off ignition
- Pull plug off the control module
- Pull plug off the servomotor for HBA
- Check for open circuit in the supply leads to the servomotor for HBA, right, terminals 5, 6, 7, 8
Ohmmeter display < 5 Ohm
- Check for short to B+ in the supply leads to the servomotor for HBA
Ohmmeter connected to terminals 5, 6, 7, and 8; measure resistance to ground
Ohmmeter display Infinity Ohm
- Check for short circuits between the leads.
- If no fault is detected in the wires, replace the servomotor for HBA.
Fault Code 3
Axle position sensor, front
(angle sensor for HBA)
This fault is stored in the following cases:
1. Short circuit to voltage/ground or open circuit in the supply leads between the control module and angle sensor for HBA, front
2. The sensor linkage is disengaged or faulty
3. Angle sensor for HBA, front, is faulty
4. The control module is faulty
Elimination:
- Visually inspect the sensor linkage and check the plastic holder of the sensor.
- Switch off ignition
- Pull plug off the angle sensor for HBA, front
- Switch ignition on
- Measure voltage between terminal 5 of the sensor plug and ground
Voltmeter display approx. 5 V
- Measure voltage between terminal 5 and terminal 1 of the sensor plug
- Voltmeter display approx. 5 V
- In the PST2 menu item Actual values, select Sensor voltage, spring travel 1 (front)
- Connect a jumper to terminals 4 and 5 of the sensor plug
PST2 display approx. 5 V
- If no fault is detected in the wires, replace the angle sensor for HBA.
Fault Code 4
Axle position sensor, rear
(angle sensor for HBA)
This fault is stored in the following cases:
1. Short circuit to voltage/ground or open circuit in the supply leads between the control module and angle sensor for HBA, rear
2. The sensor linkage is disengaged or faulty
3. Angle sensor for HBA is faulty
4. The control module is faulty
Elimination:
- Visually inspect the sensor linkage and check the plastic holder at the sensor.
- Switch off ignition
- Pull plug off the angle sensor for HBA, rear
- Switch ignition on
- Measure voltage between terminal 5 of the sensor plug and ground
Voltmeter display approx. 5 V
- Measure voltage between terminal 5 and terminal 1 of the sensor plug
- Voltmeter display approx. 5 V
- In the PST2 menu item Actual values, select Sensor voltage, spring travel 2 (rear)
- Connect a jumper to terminals 4 and 5 of the sensor plug
PST2 display approx. 5 V
If no fault is detected in the wires, replace the angle sensor for HBA.
Fault Code 5
5 V supply for axle position sensors
(angle sensors for HBA)
This fault is stored in the following cases:
1. Short circuit to voltage/ground in the supply leads between the control module and angle sensors for HBA
2. Angle sensor for HBA is faulty
3. The control module is faulty
NOTE: The 5 V supply voltage for the sensors is ensured via terminal 14 on the HBA control module. A fault in this supply lead affects both angle sensors.
Elimination:
- Switch off ignition
- Pull plug off the angle sensor for HBA, front
- Switch ignition on
- Read the fault memory and observe whether fault code 5 reappears.
If fault code 5 does not reappear, the supply lead to the angle sensor for HBA, front, is faulty. Proceed as follows in this case:
- Measure voltage between terminal 5 of the sensor plug and ground
Voltmeter display approx. 5 V
- Measure voltage between terminal 5 and terminal 1 of the sensor plug
- Voltmeter display approx. 5 V
- In the PST2 menu item Actual values, select Sensor voltage, spring travel 1
- Connect a jumper to terminals 4 and 5 of the sensor plug
PST2 display approx. 5 V
If no fault is detected in the wires or control module, replace the angle sensor for HBA, front
If fault code 5 reappears after the plug has been removed from the angle sensor for HBA, front, there is a fault in the supply lead to the angle sensor for HBA, rear. Proceed as follows in this case:
- Pull plug oft the angle sensor for HBA, rear
- Measure voltage between terminal 5 of the sensor plug and ground
Voltmeter display approx. 5 V
- Measure voltage between terminal 5 and terminal 1 of the sensor plug
Voltmeter display approx. 5 V
- In the PST2 menu item Actual values, select Sensor voltage, spring travel 2
- Connect a jumper to terminals 4 and 5 of the sensor plug
PST2 display approx. 5 V
If no fault is detected in the wires or control module, replace the angle sensor for HBA, rear.
Fault Code 6
Control module coding error
This fault is stored in the following case:
1. Control module has not been coded yet
Elimination:
- Code the control module
Fault Code 7
Calibration not carried out yet
This fault is stored in the following case:
1. A newly installed control module has not be calibrated yet
Elimination:
- Select menu item Calibration.
- Follow instructions on the screen and carry out the calibration
NOTE: Calibration is not possible if the sensor voltage lies outside the plausible range (sensor voltage less than 2 V or greater than 3 V).
- Check the sensor voltages in menu item Actual values, with the vehicle parked on a level surface (vehicle not raised)
- Check sensor holder and linkage