Checking the Actual Values
Checking The Actual Values
The specified voltage values are reference values
Test point 1
Sensor voltage, spring travel 1 (front)
- Engine off
- Vehicle on level surface
PST2 display 2 V< Us <3 V
Us = sensor voltage
The system is faulty if voltage values such as 0.4 V in the lower range or 4.5 V in the upper range are displayed. See the description for fault code 3.
Test point 2
Sensor voltage, spring travel 2 (rear)
- Engine off
- Vehicle on level surface
PST2 display 2 V< Us <3 V
Us = sensor voltage
- The system is faulty if voltage values such as 0.4 V in the lower range or 4.5 V in the upper range are displayed. See the description for fault code 4.
Test point 3
Terminal 15
- Engine off
- All loads switched off
PST2 display greater than 10 V
NOTE: Communication with the control module is not possible without terminal 15
Test point 4
Terminal 58
- Engine off
- Parking light off
PST2 display 0
- Engine off
- Parking light on
PST2 display 1
If 0 is displayed with the parking light on:
1. Check fuse A5
2. Pull plug off the control module
- Switch parking light on
- Measure voltage between terminal 10 and ground
Voltmeter display greater than 10 V
If the signal (terminal 58) is present at the control module, replace the control module. Check the wire if the signal (terminal 58) is not present at the control module.
NOTE: The headlights are not raised when high beam is activated if there is an open circuit at terminal 58 or if the control module is faulty.
Test point 5
ABS speed
- Engine off
- Vehicle raised
- Ignition on
- Slowly rotate the rear left wheel by hand
PST2 display greater than 1 km/h
If 0 km/h is displayed when the wheel is rotated:
1. Check fuse B9
2. Switch ignition off and pull off plug on the control module
- Switch ignition on
- Rotate the rear left wheel by hand and measure the voltage (AC range) between terminal 11 and ground
Voltmeter display greater than 1 V
If the wheel speed signal is present at the control module replace the control module. If the wheel speed signal is not present at the control module, check the wire for open circuit or short to ground and check the ABS or PSM control module.
Test point 6
High beam
- Engine off
- Parking light off
- High beam off
PST2 display 0
- Engine off
- Parking light on
- High beam on
PST2 display 1
If 0 is displayed with the high beam on:
1. Check fuse A 1
2. Switch ignition off and pull off plug on the control module
- Switch ignition on
- Switch the high beam on and measure the voltage between plug terminal 15 (high beam on signal) and ground
Voltmeter display greater than 10 V
If the high beam signal is present at the control module, replace the control module. If the high beam signal is not present at the control module, check for an open circuit in the wire.
Identification
The diagnosis software number and control module part number can be read out under the Identification menu item.
Fault memory
Faults stored in the control module can be read out under the Fault memory menu item.
Erase fault memory
Faults stored in the control module can be erased under the Erase fault memory menu item. Here, all stored faults are erased.
Actual values
In the Actual values menu item, the current values of the following parameters can be read out:
- Sensor voltage, spring travel 1 (front)
- Sensor voltage, spring travel 2 (rear)
- Terminal 15
- Terminal 58
- ABS speed
- High beam
Drive links
In the Drive links menu item, the servomotors for HBA can be moved to three different positions
- Servomotor in max. position
- Servomotor in center position
- Servomotor in min. position
NOTE: The servomotors cannot be activated if there are any open circuits in the servomotor circuit.
Coding
A new control module can be coded in menu item Coding.
Procedure:
1. Connect PST2 and switch on the ignition
2. Select vehicle type 911(996) and start the automatic control module search.
3. Select control module HBA.
4. Select menu item Coding.
5. Select vehicle type 911(996) and start coding with the F8 key.
Calibration
The control module can be calibrated under menu item Calibration. Calibration is necessary in the following cases:
- When replacing the servomotors for HBA
- When replacing the entire headlights
- When replacing the control module
- When replacing angle sensors for HBA
- When modifying the running gear
NOTE: Adjust the headlights after calibration.
Procedure:
1. Connect PST2 and switch on the ignition
2. Select vehicle type 911(996) and start the automatic control module search.
3. Select control module HBA.
4. Select menu item Calibration and follow the instructions displayed by the PST2
NOTE: The servomotors will be activated in the three possible positions - max. position, center position and mm. position - during calibration. Observe this process with the dipped beam switched on. Read out the fault memory after calibration.