Design [3 of 4]
Sun roof
The sun roof is operated using a switch in the same unit in the roof as for the front reading lamps. 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 sensors.
The sun roof has a sun roof module (SRM). The sun roof module (SRM) communicates with the central electronic module (CEM) using serial communication.
There are diagnostics for the sun roof.
LEDs in doors for lock indication (only C70)
Usually there are locking buttons in the doors, but the C70 does not have these. The vehicle is equipped with LEDs instead that indicate whether the vehicle is locked or not. The LEDs light for approximately 5 minutes after locking the vehicle. The LEDs are on each door and are directly connected to the Central electronic module (CEM).
There are diagnostics for the LEDs.
Twilight sensor (ECC only)
The twilight sensor consists of a photo diode powered from the central electronic module (CEM). The conductivity of the diode depends on the amount of light to which it is exposed.
The diode is under a diffusing lens which reduces the sensitivity of the photo diode to the angle of the light hitting it. Increased light intensity reduces the voltage over the photo diode.
The control module measures the voltage across the photo diode and converts the voltage to information which is then transmitted to other control modules via the controller area network (CAN).
The twilight sensor is located in the same holder as the sun sensor and alarm diode.
There are diagnostics for the twilight sensor.
Sun sensor (electronic climate control only)
The sun sensor consists of a photo diode powered from the central electronic module (CEM). The conductivity of the diode depends on the amount of light to which it is exposed.
The diode is located under a diffusing lens which reduces the sensitivity of the photo diode to the angle of the light hitting it. Increased sun intensity reduces the voltage over the photodiode.
The control module measures the voltage across the photo diode and converts the voltage to information which is then transmitted to the climate control module (CCM) via the controller area network (CAN).
The sun sensor and its housing are located in the center of the dashboard at the windshield together with the twilight sensor and alarm diode.
From and including structure week 200746, the sun sensor is replaced by twin sun sensors.
For further information, see Design and Function, climate control module (CCM).
There are diagnostics for the sun sensor.
Siren
Information from the siren control module (SCM) to the central electronic module (CEM) contains configuration and status data. This information is transmitted using serial communication.
When the alarm is activated, the siren control module (SCM) transmits continuous status signals to the central electronic module (CEM).
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 to the siren and the serial communication between the siren control module (SCM) and the central electronic module (CEM) is monitored. If the power supply for the car to the siren is broken, or the communication between the central electronic module (CEM) and siren control module fails, the siren starts to sound. 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 below the plenum chamber on the passenger side. After replacement, a new siren control module (SCM) must be configured. This is done using VIDA.
There are diagnostics for the siren.
Mass movement sensor module (MMS)
C30/S40/V50 (MY -2011)
C70
The mass movement sensor module (MMS) detects movements inside the passenger compartment using high frequency radio waves of 2.45 GHz. 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 central electronic module (CEM) which activates the alarm.
The mass movement sensor (MMS) is in the headlining in the center of the vehicle. This ensures optimum coverage of the interior of the vehicle. There are two sensors in five door cars. One is positioned in the center of the roof and the other in the roof above the cargo compartment.
There are diagnostics for the mass movement sensor module (MMS).
Ultrasonic sensor module (IMS)
C30/S40/V50 (MY 2012-)
The ultrasonic sensor module (IMS) is located in a cover on the ceiling. The ultrasound sensor (IMS) is used to detect movement inside the passenger compartment when the alarm is activated. The aim is to detect, for example, anybody attempting to reach into the vehicle to steal a bag or similar. When the sensor is activated it performs an internal self-test and reports the result to the CEM, if the test failed the CEM sets a DTC. The sensors communicate serially and are powered via the central electronic module (CEM). When the sensor is activated, it emits ultrasound in the passenger compartment. The sound waves are reflected back to the sensor and if the sensor detects changes in reflectivity or movements inside the passenger compartment, the alarm is triggered.
Note! The sensor performance is affected by air turbulence and therefore all windows and any roof hatches must be closed for the sensor to operate most effectively.
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 rain sensor module (RSM) transmits signals to the central electronic module (CEM) using serial communication. The signals contain information about:
- how much rain is hitting the windshield
- a sudden splash on the windshield
- the outside light conditions.
The central electronic module (CEM) requests a certain windshield wiper speed based on this information.
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.
There are diagnostics for the rain sensor module (RSM).
Humidity sensor (option, only ECC 2008-)
The task of the humidity sensor (HUS) is to transmit information about the passenger compartment's humidity to the Climate control module (CCM).
The sensor is part of the optional system for air quality together with the Air quality sensor (AQS) and a particle filter.
The humidity sensor is via serial communication to the Central electronic module (CEM), which transmits the information to the Climate control module (CCM) on the CAN network.
All information processing then occurs in the Climate control module (CCM).
The sensor is in the holder for the rear view mirror and is powered and diagnosed by the Central electronic module (CEM).
For further information, also see Design and Function, climate control module (CCM):
Horn
There are two horns in front of the radiator. There are four switches in the steering wheel. The horn is activated when one of these is closed.
The signal continues for as long as the switch is closed.
The horn is also activated when the panic alarm button on the remote control is pressed (certain markets).
The power supply to the horns is via a relay in the relay box in the engine compartment.
There are diagnostics for the relay for the horn.
Rear demist
There are heating loops in the glass for demisting and to prevent ice from forming. The loops heat up when they are supplied with power. The power supply is via a relay in the central electronic module (CEM).
Rear demist is controlled using a switch on the right-hand side of the climate control module (CCM).
Press the button again to switch off the function. Demisting is switched off automatically after the maximum time of 12 minutes.
On vehicles with certain diesel engines the rear demist can start without manual activation. This means that the engine sometimes needs to reach a much greater working temperature to burn soot particles that are trapped in the particle filter.
By starting the rear demist, together with other actions, the vehicle's alternator is loaded and the engine coolant temperature rises.
Read more detailed information about this function in Design and Function, Engine control module (ECM).
There are diagnostics for the relay and switch.
Switch clutch pedal (4-cylinder)
The clutch pedal switch is positioned together with the clutch pedal. In resting position the switch is open. It closes when the clutch pedal is pressed down by more than 90% of its entire stroke length. When the switch is activated, a signal is transmitted to the central electronic module (CEM).
For further information about the immobilizer, see Design and Function, Immobilizer.
Clutch pedal sensor (5-cylinder)
Cars with 5-cylinder gasoline engines have a position sensor for the clutch pedal. The sensor is affected when the clutch pedal is pressed. The sensor then sends a signal (voltage level) which is proportional to the degree to which the clutch pedal has been pressed.
The position sensor is directly connected to the central electronic module (CEM). The control module receives and processes the signal. The information is used in difference ways depending on the equipment level of the car.
The signal is used as part of the conditions for the immobilizer.
For further information about the immobilizer, see Design and Function, Immobilizer.
Power windows
All side windows are operated by motors in the doors. The switches for operating the windows are in each door panel. All windows can be operated from the control panel in the driver's door.
For further information, see Design and Function, Door control modules.
For greater comfort, all windows including the sun roof can be opened. This is done by holding in the unlock button on the remote control for 1.5 seconds. In the same way, all windows including the sun roof can be closed at the same time. This is done by holding in the lock button on the remote control for 1.5 seconds.
This function can also be activated from inside the passenger compartment. If the lock or unlock button is held in on either of the front door panels the same function will be obtained.