Design

Design

Siren control module (SCM)




Information transmitted by the siren control module (SCM) to the upper electronic module (UEM) contains configuration and status information. This data is carried via serial communication.
When the alarm is activated the siren sends continuous status signals to the upper electronic module (UEM).
The siren has a battery and a built in battery charger so that it is independent of the power supply in the car. The battery charger maintains battery voltage in the integrated battery. When the alarm is activated, the power supply for the siren and the serial communication between the siren and the upper electronic module (UEM) are monitored. The siren sounds if the car's power supply to the siren is broken or if communication between the upper electronic module (UEM) and the siren is interrupted. The battery and battery charger in the siren cannot be replaced separately. The entire siren must be replaced in the event of a fault.
The siren is in a protected location under the fender liner in the front right-hand wheel arch. The siren must be configured after replacement. Configuration is carried out using VIDA.
There are diagnostics for the siren.

Sun roof




The sun roof module (SRM) is operated by one switch. The switch is located in the same unit in the roof as the front reading lamps and the courtesy lighting. The sun roof can be opened and closed as well as angled up slightly at the rear edge.
The sun roof is driven by a motor which is in the roof, in front of the sun roof. The position of the sun roof is determined by two optical sensors. The sun roof has a sun roof module (SRM) which manages communication.
There are diagnostics for the sun roof.
For further information, see Design and Function, Sun roof.

Mass movement sensor module (MMS)




The mass movement sensor module (MMS) detects movements inside the passenger compartment using high frequency radio waves. The Doppler effect principle is used to determine whether the frequency of the received microwave is different from the transmitted microwave. If the frequency has changed, this is interpreted as a movement in the vehicle. If a movement is detected, a trigger signal is transmitted to the upper electronic module (UEM) which activates the alarm.
Mass movement sensors (MMS) are located in the ceiling, in the center of the vehicle, to optimally cover as much as possible of the vehicle's volume. In XC90 there are two mass movement sensors (MMS), one front and one rear. These are connected in parallel to the central electronic module (CEM) and share wiring for voltage supply and communication.
The mass movement sensor module (MMS) is powered from the upper electronic module (UEM) and earthed in the body.
There are diagnostics for the mass movement sensor module (MMS).

Rain sensor module (RSM)




The rain sensor module (RSM) uses optical measurement to detect water on the windshield. An infrared beam of a fixed intensity lights part of the windshield. The intensity of the reflected beam is measured and compared to the intensity of the transmitted beam. If there is water on the surface of the windshield, the beam will be distorted and some of its intensity lost. If the beam is not fully reflected, this is interpreted as water on the windshield and the windshield wipers start.
The signals from the rain sensor module (RSM) to the upper electronic module (UEM) are carried via serial communication. The rain sensor module (RSM) transmits the signals to the upper electronic module (UEM). These signals request a particular windshield wiper speed (depending on the amount of rain falling on the windshield), indicate that a sudden large splash has hit the windshield and register the light conditions outdoors.
The rain sensor module (RSM) is in front of the rear view mirror on the inside of the windshield. Cars with rain sensor modules (RSM) have a special windshield.
The rain sensor module (RSM) is powered by the upper electronic module (UEM).
There are diagnostics for the rain sensor module (RSM).

Interior roof lighting




There are a number of lamps inside the passenger compartment. The lamps include four reading lamps and a general courtesy lamp.
In XC90 models with three rows of seats there are 6 reading lamps.
The front left and front right reading lamps and the courtesy light are located in the same unit in the roof, just above the rear view mirror. The other reading lamps are in the roof above the rear seat(s).
These lamps transmit control signals to the control module. These signals allow the control module to determine the status of the lamps and switches. This allows any faults to be detected. For example:
- a blown bulb
- an open-circuit in a cable
- that the switch has jammed in the pressed in position.
The control signals are divided up as input signals at a number of inputs in the upper electronic module (UEM). The control signal for the courtesy lighting shares the same inputs as control signals for the front reading lamps. The rear control signals for the reading lamps each have their own input. If there is a third row of seats, there is a separate input for the control signals for this row.
Two different lighting times can be programmed using VIDA depending on the requirements of the customer. For further information, see: Downloading software and replacing the control module Upper Electronic Module (UEM)
There are diagnostics for all lamps in the inner roof lighting.

Remote control




The remote control can be used to:
- lock and unlock the doors
- unlock the tailgate (V70, XC70 and XC90)
- open the trunk lid (S80 and S60)
- activate the approach lighting
- activate the panic alarm (certain markets).
The receiver is in the rear view mirror and transmits signals to the upper electronic module (UEM). These signals determine:
- which function should be activated
- at which frequency the receiver receives the signal from the remote control
- which of the remote controls transmitted the signal
- the signal strength received from the remote control.
Up to six remote controls can be stored in the upper electronic module (UEM). The control module stores the identity and PIN for each remote control.
The remote control identity and PIN are also stored in the Volvo central database When replacing the upper electronic module (UEM), this data is transmitted to the vehicle. This means that the remote controls do not need to be replaced and can be used with the new control module.
The remote control has two PIN codes, one with 16 characters and one with 8.
If the vehicle has seats and door mirrors with memory, these functions are affected by the remote controls stored in positions 1, 2 and 3. When the car is unlocked using one of these remote controls and the driver's door is opened the information about which remote control unlocked the car is stored. The setting for the driver's seat and the door mirrors is stored in that remote control at the same time that the car is put to "sleep mode". (Sleep mode means that the car continues in stand-by mode with low energy consumption, which occurs when the ignition key is removed and no function is activated for approximately 5 minutes). The next time that the car is unlocked using that particular remote control the driving seat and the door mirrors will be set to the same positions that they were in when the car stored the information.
The remote control battery can be replaced.

Rear view mirror




The rear view mirror has an automatic anti-dazzle function for when light from behind the car is too bright in the mirror (option in certain markets).
There is one photo sensor on the reverse of the rear view mirror and another on the front. Both sensors compare the intensity of the light through the windshield and from the rear of the vehicle. If the difference exceeds a certain value, the anti-dazzle function is activated to the required degree. The upper electronic module (UEM) receives and processes the signals from the two photo sensors.
The anti-dazzle function can be set to the customer requirements. For further information, see: Downloading software and replacing the control module Upper Electronic Module (UEM)
There are diodes in the rear view mirror above the mirror glass. These are for the seat belt reminder and for the PAD (passenger airbag deactivated) lamp.

Note! The rear view mirror with automatic anti-dazzle can only be installed in the factory. Upgrading to, or removing an anti-dazzle rear view mirror cannot be carried out after market due to software limitations.

There are diagnostics for the functions in the rear view mirror.

Tire pressure monitoring system (TPMS)




The purpose of the tire pressure monitoring system, TPMS, is to enable the driver to have optimum tire pressure by giving a warning when the pressure in any of the tires becomes too low. Correct tire pressure is important for:
- achieving good fuel economy
- achieving optimum comfort and good driving characteristics
- preventing flat tires due to too low tire pressure.
The function is integrated in the Upper electronic module (UEM). Sensors are installed together with the air valve on each wheel to measure the air pressure in the tires.

Note! The system must be regarded as a driver aid to maintain the correct tire pressure. The system must NOT be regarded as a warning system that indicates that there is a serious problem with the vehicle. No tire is completely sealed - there is always slight leakage as the tire can never be completely sealed to the rim. When inflating the tire with air, you must, as much as possible, ensure that the tires are at same temperature as the outside temperature. Furthermore, "Comfort pressure" should not be applied as this gives a tire pressure that is too close to the parameter for the monitoring system, which means that even small changes in temperature or load can cause the pressure in the tires to be too low for the system to consider acceptable. When inflating with air, the tires must be filled to the pressure stated on the decal located on the car body. The pressure is calculated with regard to fuel economy, comfort and safety. Therefore, these pressures MUST be followed. If the decal is missing or damaged, a new one must be ordered and applied. This is especially important on vehicles with TPMS.

Tire pressure sensor




The tire pressure sensors are installed together with the air valve on the rim. The sensor consists of a pressure sensor, a communication circuit, an acceleration sensor and a battery.

Note! Special procedures are required for removing the tire from the rim depending on vehicle model and tire type. This is to prevent damaging the sensor. See the specific mechanical information instruction under Repairing/Removal, replacement and installation.

Seat belt reminder




There is a lamp in the upper electronic module (UEM) for the front seat belt reminder. The sensors for the seat belt reminder are in the seat belt buckles. The upper electronic module (UEM) receives information from the supplemental restraint system module (SRS). This information indicates where the seat belt buckle is engaged and whether there is someone in the seat. If someone is in one of the front seats and the seat belt buckle is engaged, the seat belt reminder lamp goes out.

Warning lamp for passenger airbag disconnected (PAD)




There is a PAD (passenger airbag deactivated) warning lamp in the upper electronic module (UEM). This function varies depending on the market. If the passenger airbag is deactivated or a fault has occurred which will prevent activation of the passenger airbag, this lamp will light up. For more information, see Design and Function, supplemental restraint system module (SRS).

Compass




The compass is integrated in the rear view mirror. The compass display is integrated in the mirror glass. The display is a vacuum-fluorescent type. The display luminance is regulated via the internal light sensor in the rear view mirror. When the vehicle is started, all the segments light up in the display. All the segments then go out after a couple of seconds. The display then functions normally. The compass has a button (1) which is used to:
- set the magnetic zone in which the car is being driven
- calibrate the compass.

Magnetic zones




In many places, magnetic north is different from true north. In order to compensate for this difference, the compass uses a method that divides the globe into 15 different zones. If the compass is not set for the zone in which the vehicle is being driven, it may display the wrong direction. If the vehicle is transported between different zones, the magnetic zone setting must be altered manually.




The correct zone must be selected for the compass to work correctly.
1. Ignition position II.
2. Hold the button on the reverse of the rear view mirror in for approximately 3 seconds until ZONE is displayed (use, for example, a straightened paperclip) The number for the actual area is displayed.
3. Press the button repeatedly until the number (1-15) for the relevant geographical area is displayed.
The display reverts to the compass direction after a few seconds, this means that the zone change is complete.

Calibration
Calibration of the compass is necessary for it to display the correct direction. During calibration, the compass detects the magnetic field from the vehicle, which must be taken into consideration when calculating the compass direction. If strong magnetic fields affect the compass, such as for example, an antenna close to the mirror, or if changes in direction occur too quickly, the compass shows the last measured direction until a new measurement is successful. The direction will not be updated if the vehicle is stationary.

The compass must be calibrated when:
- the display does not show a compass direction within a couple of seconds. This may be due to a highly magnetic object, such as an antenna, being placed in the vicinity of the compass.
- the compass does not display the correct direction, even though the correct magnetic zone has been set.
The compass may need calibrating to display correctly. For best results, switch off all large power consumers such as interior lighting, blower fan, rear demist etc. and avoid having metal objects and magnetic objects near the mirror.
1. Stop the vehicle in a large open area with the engine running.
2. Hold the button on the reverse of the rear view mirror in (use a paperclip for example) until CAL is displayed (approximately 6 seconds).
3. Drive slowly in a circle at no more than 8 km/h until CAL disappears from the display. Calibration is complete.
Alternative calibration step: set off as normal, CAL disappears from the display when calibration is complete.