Part 2
Function (Continued)
Interior/footwell/sun visor/glove compartment lighting
Note! The market in Japan has Remote Keyless Entry (RKE) regardless of if the vehicle is equipped with keyless entry system or not. When the vehicle is not equipped with keyless entry system, the Remote Keyless Entry (RKE) communicates directly with Central electronic module (CEM). If the vehicle is equipped with keyless entry system, the Remote Keyless Entry (RKE) communicates via Keyless Vehicle Module (KVM).
The interior roof lighting front (10/22) and rear (10/150) a total of four lamps is activated by the relevant switch.
The inner roof lighting and courtesy lighting (10/125-126) are automatically activated when a door is opened, when the vehicle is unlocked using the remote key or upon activation of approach lighting.
In order for the automatic activation to function the light switch in the roof console must be in the auto position. This only applies to roof lighting. The courtesy lighting is activated regardless of the position of the light switch.
The inner roof lighting and courtesy lighting are powered by the central electronic module (CEM). The inner roof lighting and courtesy lighting may dim when the central electronic module activates/deactivates general lighting since the return cable for inner roof lighting to the central electronic module (CEM) is adjustable.
Courtesy lighting activated:
- when the request for courtesy and roof lighting is transmitted from the remote receiver to the central electronic module (CEM) using serial communication
- when the remote control receiver has received a command to unlock from one of the remote keys
- when one of the doors is opened.
Sun visor lighting (10/114-115) and glove compartment lighting (10/29) are powered by the central electronic module (CEM). The lamps for sun visor lighting are activated when the lid to the vanity mirror is opened. The lamps for glove compartment lighting are activated when the glove compartment is opened.
Cargo compartment lighting
Cargo compartment lighting is activated when the trunk lid is opened. When the trunk lid is opened, the switch in the lock unit (6/8) is activated.
The lamps (10/127-128) are supplied power by the central electronic module (CEM) (4/56) via an internal interior lighting relay.
Rear demist
The rear window defroster (9/2) is activated by pressing the switch on the climate control module (CCM) (4/6). The climate control module (CCM) transmits the data to the central electronic module (CEM) (4/56) via the CAN network.
The central electronic module (CEM) checks to ensure that the defroster start conditions are fulfilled. If so, the central electronic module (CEM) activates the relay (2/82) located on the rear relay box and the defroster is supplied power via the relay.
Automatic activation of the rear demist (9/2) can be set in the climate settings in the menu for the Infotainment control module (ICM) (3/281). Rear demist starts in connection with starting the engine and an outdoor temperature below +9 °C.
On activation of auto defrost rear in the climate settings the Infotainment control module (ICM) transmits to the central electronic module (CEM) that auto defrost rear has been activated. The central electronic module (CEM) saves the value and responds to the Infotainment control module (ICM) that auto defrost rear is activated, which means the Infotainment control module (ICM) checks the option in the climate settings.
The central electronic module (CEM) also transmits a request via the Control area network (CAN) to the climate control module (CCM) to light the LED in the switch.
When the function is switched off, either by pressing the switch on the climate control module (CCM) or that auto defrost rear switches off the function, the LED in the switch on the climate control module (CCM) goes out.
Fuel pump
The central electronic module (CEM) (4/56) receives a request to start the fuel pump from the engine control module (ECM) (4/46) via CAN network. The central electronic module (CEM) then activates an internal relay that supplies power to the fuel pump unit (4/83), which in turn powers the fuel pump (6/33).
If the CAN network does not function the relay for the power supply to the fuel pump control module will not be activated.
In the event of a collision in which the airbags are deployed, a signal is transmitted from the supplemental restraint system (SRS) module (4/9) to the central electronic module (CEM) via the CAN network. The central electronic module (CEM) deactivates the relay for the fuel pump unit.
Fuel level (Gasoline/Diesel)
The fuel level is gauged with the fuel level sensor (7/130). The sensor sends a signal to the central electronic module (CEM) (4/56).
Vehicles without AWD have a sensor located on the pump side in the fuel tank. Vehicles with AWD have two sensors located on opposite sides of the fuel tank. Two sends are used to ensure the correct fuel quantity is indicated regardless of the inclination of the vehicle. The central electronic module (CEM) calculates the amount of fuel remaining by comparing the signal with a tank table. Information on fuel quantity is sent via the CAN network to the driver information module (DIM) (5/1), where fuel level is indicated via the fuel gauge.
Power steering
The unit for speed dependent power steering sits beneath the dashboard above the glove compartment.
The unit receives a control signal from the central electronic module (CEM) regarding the current the servo pump is allowed to use with the help of direction change. The permitted current limit depends on power consumption in the vehicle at that moment and a calculated value based on vehicle speed. The power steering unit serves as a current booster and sends a control signal on permitted current to the servo pump. All logic and control lies in the central electronic module (CEM). The servo pump is supplied power from a relay in the engine compartment relay and fuse box at ignition position II.
The central electronic module (CEM) also has the task of limiting power consumption in certain applications. Therefore in certain conditions it may be necessary to decrease or shut off the power steering.
The central electronic module (CEM) can set the power consumption of the power steering in five stages:
- 100% of normal power consumption
- 75% of normal power consumption
- 50% of normal power consumption
- 25% of normal power consumption
- 0% of normal power consumption.
Upon limitation of servo pump power consumption, information is sent via the CAN network to the driver information module (DIM) (5/1), which lights the general warning lamp and displays a text message.
Electrical additional heater (certain markets)
The climate control module (CCM) (4/6) checks the function of the electric auxiliary heater.
The central electronic module (CEM) (4/56) transmits information regularly to the climate control module (CCM), for example, about the permitted size of the current consumption.
The climate control module (CCM) uses this information to prioritize between its loads. The climate control module (CCM) also uses the information to calculate how much output must be used to activate the electrical additional heater (9/41).
The central electronic module (CEM) receives information from the climate control module (CCM) via the CAN network.
The central electronic module (CEM) checks that the output voltage is not too great. See: Current limiting
The power consumption of the electric auxiliary heater is regulated via a pulse-width modulated signal from the central electronic module (CEM).
Rain sensor
The rain sensor module (RSM) (7/149) senses water on the windshield. The rain sensor (RSM) assesses the information based on volume of water on the windscreen and the prevailing exterior light conditions. This information is transmitted via the central electronic module (CEM) (4/56) on to the wiper motor module (WMM) (6/1) via serial communication. The wiper motor module (WMM) in turn ensures that the windscreen wipers are set to the correct speed.
The rain sensor module (RSM) senses if the windscreen is dirty or covered with traffic film and automatically compensates accordingly. The rain sensor module (RSM) also senses heavier splashes on the windscreen. The windscreen wipers then operate at top speed.
The rain sensor module (RSM) communicates with the central electronic module (CEM) via serial communication. Power is supplied via the relay for extended feed. The relay is checked by the central electronic module (CEM) and is activated when the ignition is in position I or II. The rain sensor module (RSM) is powered for 3 seconds after the ignition has been switched off.
The steering wheel module (SWM) (3/130) transmits the signal via the LIN communication to the central electronic module (CEM) indicating the position of the windshield wiper stalk and the status of the rain sensor switch. If the rain sensor switch is activated on the wiper stalk, the central electronic module (CEM) transmits the information to the rain sensor module (RSM) which is activated.
The rain sensor module (RSM) transmits information to the wiper motor module (WMM) via the central electronic module (CEM). The sensitivity can be adjusted using the collar on the wiper stalk.
If a fault occurs in the rain sensor module (RSM), the central electronic module (CEM) transmits an error message to the wiper motor module (WMM). If there is a fault message when the rain sensor module (RSM) is active, the wiper motor module (WMM) selects top speed for the windshield wipers until the rain sensor (RSM) is deactivated. If the fault recurs, wiping will only be activated when the wiper stalk is next moved to the single sweep or slow speed position.
Sun roof
Note! Vehicles with panoramic roof (option XC60) works in the same way as vehicles with roof opening panel.
The sunroof is equipped with a sunroof module (SRM) (4/33) that handles its functions. The sunroof is operated via a switch on the roof panel.
The Central electronic module (CEM) (4/56) transmits information about the vehicle's speed to the Sun roof module (SRM). This information is used to calculate how much force is required from the motors to operate the sun roof. The Sun roof module (SRM) also receives signals from the Central electronic module (CEM), via a directly connected cable, whether to carry out a "comfort open" or "comfort close" or to carry out a sun roof initialization.
Horn
The horn (16/10-11) is located behind the radiator grille. The horn is supplied power from the horn relay (2/17) in the engine compartment fuse and relay box. The horn is activated when a switch in the steering wheel is closed. The closure is detected by the steering wheel module (SWM) (3/130), which sends a signal to the central electronic module (CEM) (4/56). The central electronic module (CEM) forwards a ground closure on one of its outputs, grounding the signal horn relay and activating the relay.
The horn is grounded in the body.
Clutch pedal switch/clutch pedal sensor
Depending on vehicle configuration, there is a switch and a sensor located at the clutch pedal. These are used to indicate a depressed pedal. They are used by functions such as the immobilizer and autostart.
The clutch pedal sensor, external, is directly connected to the Central electronic module (CEM) where it also powered and grounded. The sensor gives different output signals depending on how long the clutch pedal is pressed down. The sensor is only found on vehicles with manual transmission.
The switch closes when the clutch pedal has been depressed about 75% of the way.
The contact breaker is directly connected to the central electronic module (CEM), to the engine control module (ECM) and the Keyless vehicle module (KVM) if the vehicle is equipped with keyless functions. When the contact breaker closes, a ground connection occurs on connected control modules. The contact breaker is used to obtain redundancy to the output signal for the clutch pedal sensor, external.
The signals are used for different purposes, including during the start attempt as a depressed pedal is a requirement from the immobilizer system in order to start the vehicle.
The central electronic module (CEM) does not use input signals from the sensor and switch for its internal functions. These input signals are, however, forwarded on the CAN network, where they are interpreted by other control modules, such as the engine control module (ECM). The central electronic module (CEM) does, however, use the input signals to be able to diagnose the switch and sensor and generate a diagnostic trouble code should a fault arise.
Accelerator pedal (AP) position sensor
The accelerator pedal position sensor is mounted together with the accelerator pedal. The sensor transmits a pulse width modulated signal that is proportional to how much the pedal is depressed. The sensor is directly connected to the central electronic module (CEM), which forwards the sensor value out onto the CAN network. The central electronic module (CEM) only uses the signal to be able to generate a diagnostic trouble code should any sensor output signals fall outside of specified values.