Electronics - Design and Function - 2 of 4: Other Volvo C70 II

AIR CONDITIONING

See: AIR CONDITIONING

AIR DISTRIBUTION SYSTEM

See: AIR DISTRIBUTION SYSTEM

Scheme 632

The blower fan provides the airflow through the vehicle.

The blower fan must be operating before the climate control system can be engaged.

Scheme 633

The particle filter cleans the air of particles such as dust and pollen, which would otherwise pass through the air intake into the passenger compartment.

The multi-filter has the same function as the particle filter, but also neutralizes unpleasant smells and keeps the air as free from gases as possible. In vehicles that have the multi-filter, known as the air quality system (AQS), there is also an outside air sensor that ensures that the recirculation closes in the event that the content of gases in the outside air increases. This increases the service life of the multi-filter.

Scheme 634

The task of the heat exchanger is to provide heat for the passenger compartment.

Scheme 635

The electric PTC element speeds up the supply of heat to the passenger compartment when cold-starting. It is automatically connected when starting in cold conditions.

Scheme 636

The additional heater/parking heater produces heat by burning gasoline. The heat is distributed via the engine cooling system to the heat exchanger and on out into passenger compartment.

When the engine is running, the additional heater can provide extra heat to the passenger compartment in the event that the engine is unable to provide sufficient heat. When the engine is not running, the parking heater can heat the passenger compartment (and the engine). This function can be started directly or using a timer.

In order to start the additional heater, all the following conditions must be satisfied

1. The engine speed (RPM) is higher than 500 RPM. (The additional heater will not operate while the engine is being started - minimizing the risk of the battery becoming too weak.)
2. The ambient temperature is below 5 °C
3. The driver has selected a temperature for the passenger compartment that demands additional heat and the blower fan is operating
4. The fuel level is above 5 liters.

The additional heater is switched off when one or more of the following conditions are satisfied

1. The engine speed (RPM) is lower than 400 RPM
2. The ambient temperature is above 11 °C
3. The driver has selected a temperature for the passenger compartment that does not demand additional heat and the blower fan is switched off
4. The fuel level is below 3 liters.

The parking heater is controlled via the turn signal lamp stalk. The information appears in the driver information module (DIM). When the engine is started, after the parking heater has been switched on, the parking heater will remain in operation for a further 2 minutes. During these 2 minutes, the heater detects whether all the conditions have been satisfied in order for it to remain switched on. This is to avoid stopping and restarting the heater.

Scheme 637

The air distribution system distributes the air to the passenger compartment. It is used jointly by the heating system and the cooling system in the climate control system. The blower fan draws air into the system.

Fresh air is taken from through the gap between the hood and the windshield.

The air passes through the filter and the evaporator, past the temperature damper and possibly though the heat exchanger, before being released into the passenger compartment through the vents.

After circulating, the air disappears out of the passenger compartment though air vents at the rear of the vehicle.

THE DAMPERS

The task of the dampers is to control the amount of air that goes to each air duct and on out into the passenger compartment.

The temperature damper controls how much air goes through or outside of the heat exchanger. The split temperature damper on vehicles with electronic climate control (ECC) means that it is possible to set different temperatures on the driver's side and passenger side.

RECIRCULATION

The recirculation damper regulates the amount of incoming fresh air. The recirculation function makes it possible to prevent outside air from entering the passenger compartment, for example when the ambient air is contaminated with exhaust fumes, smoke, etc. This function can also be used for rapid heating or cooling of the passenger compartment.

If the recirculation function is used for an extended period, the air humidity in the passenger compartment increases. This is due to the moist air exhaled by the passengers. This can result in mist on the windows.

In the max. cooling control position, approximately 85% of the incoming air is taken from the passenger compartment and approximately 15% from outside. This produces more rapid cooling of the passenger compartment air.

In vehicles with an air quality system (AQS), the transition to recirculation takes place automatically if the level of contaminants in the outside air increases.

Scheme 638

The vents are adjustable so that the air can be throttled, blocked or steered in the desired direction.

If the side vents are aimed at the side windows, they help to remove mist from the windows.

DEFROSTER VENTS

Mist forms easily on the windows in cold, damp weather. The defroster vents release air towards the front windows. The air flow removes the mist that forms. As the air is dry, the airflow also prevents moist air from the passenger compartment reaching the glass, so countering misting. The air conditioning contributes significantly to these functions by dehumidifying the air at temperatures above 0 °C.

FLOOR VENTS

The four floor vents release heated or cooled air at the feet of the driver and passenger.

EVACUATION VALVES

The evacuation valves are used to even out the pressure in the passenger compartment.

The rubber dampers in the evacuation valves open when the air pressure is slightly higher in the passenger compartment than outside. When the air pressure is the same on the inside and the outside, the rubber dampers close. This prevents water from penetrating the passenger compartment.

Scheme 639

The air conditioning only functions at ambient temperatures above 0 °C. At temperatures lower than this, the pressure in the system is too low and the compressor is never engaged.

The air conditioning only functions when the engine is running. It functions regardless of engine speed (RPM) and vehicle speed. The blower fan must also be operating before the climate control system can be engaged.

The air conditioning system has only two positions, off and on. If it is too cold in the passenger compartment, the temperature can be controlled with the normal heat and blower fan controls.

Air conditioning is based on the same principle as that used in refrigerators.

Scheme 640

1. Compressor
2. Condenser
3. Engine cooling fan (FC)
4. Fixed throttle valve
5. Evaporator
6. Blower fan
7. Receiver.

Explanation

A - High pressure, warm fluid

B - Low pressure, cold fluid

C - Low pressure, cold gas

D - High pressure, warm gas

Dark arrow - Warm air

Light arrow - Cold air

By allowing the refrigerant to circulate in the closed system and changing the pressure and volume it will change temperature and boil (evaporate). At the pressure found in the system, approximately 170 - 320 kPa (1.7 - 3.2 bar), the refrigerant boils at approximately 0 to +4 °C.

A condition of the refrigerant boiling is that the heat is accessible. This heat is taken from the air around the evaporator where boiling occurs. When the heat is taken up by the refrigerant the surrounding air becomes cooler. It is this cooled air that is blown into the passenger compartment by the climate control system blower fan. The heat taken up by the refrigerant in the evaporator is transported out to the engine compartment, where it is transferred to the air by the condenser. The condenser is cooled by the airflow and the engine cooling fan (FC).

Scheme 641

The task of the compressor is to

1. draw gaseous refrigerant from the evaporator
2. compress the gas thereby increasing its pressure and temperature
3. expel the gas with high pressure and high temperature to the condenser.

The compressor takes in cold refrigerant gas from the receiver on the intake side through the low pressure connection.

In ideal conditions, the compressor compresses the refrigerant from approximately 200 kPa (2 bar) to between 1.2 MPa and 2.1 MPa (12 and 21 bar). During the process, the refrigerant heats up from 0 °C to between 70 °C and 110 °C. These pressure and temperature values apply when the system is operating under optimal conditions.

The relief valve, located on the rear section of the compressor, functions as an extra safety device. The valve opens and releases refrigerant when the pressure in the system is too high (at approx. 3.5 MPa (35 bar)). The valve then shuts again when the pressure has returned to normal.

The temperature of the refrigerant gas can increase to as much as 125 °C.

The compressor can only compress gases, as liquid would damage the compressor.

Scheme 642

1. Inlet on the high pressure side
2. Filter insert
3. Internal diameter of the throttle valve
4. O-ring
5. Outlet on the low pressure side.

The task of the throttle valve is to

1. regulate the quality of refrigerant that flows through en-route to the evaporator
2. separate the high pressure side from the low pressure side.

Upstream of the throttle valve is the refrigerant in liquid form at high pressure.

The throttle valve ensures that the correct amount of refrigerant is released to the evaporator. The quantity of refrigerant must be sufficient that the final remains evaporate precisely before the evaporator outlet.

Too little refrigerant causes the refrigerant to evaporate quickly and the vapor to overheat. This results in reduced cooling capacity.

Too much refrigerant means that some of the refrigerant does not evaporate, but is heated up. This results in reduced cooling capacity. In addition there is the risk that some of the refrigerant in liquid form reaches the compressor. This may damage the compressor because liquid cannot be compressed.

Scheme 643

The task of the evaporator is to cool and dry the air.

Heat is extracted from the air that flows over the outside of the evaporator housing. In this way, cooled air is directed into the passenger compartment. In the evaporator the heat is transferred from the warm air to the cold refrigerant. The refrigerant then begins to boil and evaporates.

The refrigerant, in liquid form, is injected into the evaporate in precisely measured volumes. The refrigerant evaporates as a result of the sudden drop in pressure and emits heat energy during this process.

When the air entering the passenger compartment encounters the cold evaporator, the humidity in the air condenses on the evaporator. The water drains out under the vehicle via a drain hose. In the event of high humidity, this may be considerable quantities of water, which is often mistaken for a water leak from the engine for example. Water that condenses binds and takes with it some of the dust and the larger impurities in the air. Therefore the air conditioning system also helps to purify the air.

The refrigerant volume that is measured by the throttle valve is injected into the evaporator. As soon as the refrigerant enters the cooling pipes, it evaporates due to the drop in pressure. During this process, heat is also extracted from the cooling pipes. The cooling pipes and the entire evaporator cool immediately. The refrigerant gas is then drawn out using the compressor.

The airflow through the evaporator is cooled and dried, and then forwarded to the passenger compartment via the air distribution ducts.

During this process, the moisture in the air condenses on the evaporator flanges. Dust, pollen, etc., which is deposited on the damp evaporator is rinsed away. This cleans and dries the air.

Scheme 644

The task of the receiver is to

1. function as a filter, taking up and binding moisture (water) found in the system refrigerant oil leak detection dye.
2. protect the compressor from refrigerant in the liquid phase (separates refrigerant in gaseous form and liquid form) refrigerant oil leak detection dye.
3. function as a storage container for: refrigerant oil leak detection dye.

The leak detection dye mixes with the oil. When a leak occurs, it is possible to locate the leak with UV light.

Scheme 645

The task of the condenser is to cool, so converting the hot, gaseous refrigerant to a liquid.

The compressor pumps in hot refrigerant gas under high pressure. The gas has a temperature of between 70 and 110 °C in the intake on top of the condenser.

When the hot gas flows through the pipe loop, it is cooled down and condensed. The heat that is removed from the gas during this process is transferred to the surrounding air. The engine cooling fan (FC) increases the airflow through the condenser. This increases the transfer of heat from the refrigerant to the outside air.

The fan is controlled with the aid of a high pressure switch or a linear high pressure sensor located in the refrigerant line. The fan is also controlled by the fan thermostat located in the coolant circuit.

Scheme 646

1. Service valve for emptying and vacuum pumping.
2. Service valve for emptying, vacuum pumping and filling of refrigerant.

The service valves are used for

1. checking the system through manometer connections
2. draining the system of refrigerant
3. vacuum pumping
4. filling of refrigerant, which normally takes place on the low pressure side but can also take place on the high pressure side in an orifice system such as this.

Scheme 647

The climate control system is no longer a luxury item in modern vehicles. It has instead become a factor for active safety, and can now be considered part of the safety equipment in the vehicle.

Reduced passenger compartment temperature - increased safety.

It is well documented that the human performance abilities are reduced in heat. Research carried out in traffic and in a normal vehicle demonstrated that when the passenger compartment temperature was increased from 21 to 27 °C

1. the risk of the driver missing important traffic information (hazard warnings, traffic signals, signs etc.) increased by 50%
2. driver reaction times were 22% slower.

With an air conditioning system in the vehicle, car travel is both more comfortable and safer.

A climate control system provides increased comfort by

1. cooling the air in the event of high temperatures in the surrounding air or in warm, sunny conditions
2. warming the air in the event of low temperatures
3. dehumidifying the air
4. filtering the air.

The relative humidity of the air is extremely important for our well-being. We perceive a relative humidity of 30-60% to be comfortable, as the moisture that is given off by the human body can easily be absorbed by the surrounding air.

If the humidity exceeds 75%, we perceive it to be oppressive and uncomfortable in warm weather, as the air cannot absorb much more moisture. For this reason, the climate control system is designed to regulate both temperature and air humidity.

The vehicle is equipped with either

1. Electronic climate control, ECC
2. Manual climate control, MCC.

Scheme 648

Electronic climate control, ECC

ECC is a fully automatic climate control system that has air conditioning and the option of manual settings. Using this system it is possible to set different temperatures on the driver's side and the passenger side.

Scheme 649

Manual climate control, MCC

MCC is a manual climate control system with air conditioning.

The climate control system comprises a heater and an air conditioner. These are combined in the distribution housing to form a single unit with a shared ventilation system for distributing heating and cooling in the passenger compartment.

The system mixes the air, i. e. hot and cold air are mixed to achieve the desired temperature. One advantage of this is that the temperature in the passenger compartment can be changed quickly if required. Another advantage is that the ECC system compensates extremely quickly when the external conditions change.

The climate control module (CCM) controls the climate control system and the buttons in the dashboard environment panel.

The climate control system also includes a number of sensors.

As an option, it is possible to have an additional heater/parking heater. When the engine is running, the additional heater can provide extra heat to the passenger compartment (and the engine).

The parking heater can heat up the passenger compartment (and the engine) when the engine is not running. This function can be started directly or using a timer.

Scheme 650

The start time of the heater is programmed by the driver selecting the desired function using the stalk on the steering wheel module (SWM) and the driver information module (DIM). The driver information module (DIM) transmits the information on to the central electronic module (CEM).

Approximately 50 minutes before the desired departure time, the central electronic module (CEM) transmits information to the combustion preheater module (CPM) about

1. outside temperature
2. quantity of fuel
3. the operating status of the vehicle
4. a request to calculate the start time of the heater.

The combustion preheater module (CPM) calculates the start time, based on information from the central electronic module (CEM), and starts the heater at the calculated time.

The climate control module (CCM) is activated when the engine coolant temperature (ECT) is greater than +30 °C. The blower fan starts and distributes the air in the passenger compartment.

When the heater is started directly using the control stalk, it runs until it is shut off or for a maximum of 60 minutes. The heater fan remains activated for 10 minutes after the set time to allow for the driver getting to the car late.

When the heater is activated, the information lamp in the driver information module (DIM) lights. The lamp goes out when the heater is deactivated. If the heater is activated and the driver locks the vehicle, the information lamp will go out approximately 25 seconds after the vehicle is locked. If the heater or the timer are activated and ignition is switched on, a text message will be displayed in the driver information module (DIM).

Certain conditions must be met before the heater can start. These are

1. outside temperature below +25nbsp; °C (at 25 °C the heater switches off)
2. quantity of fuel more than 4.5 liters for the parking heater and 7.5 liters for the engine coolant heater
3. no diagnostic trouble code (DTC) preventing the heater from starting are stored in the control module
4. an airbag has not deployed.

When the conditions are met, the heater glow plug is activated for 1 minute.

A diagnostic trouble code (DTC) is stored in the combustion preheater module (CPM) if the heater makes two failed start attempts. The combustion preheater module (CPM) will not attempt to start the heater again until the next operating cycle. A diagnostic trouble code (DTC) is stored in the combustion preheater module (CPM) after ten operating cycles with failed start attempts. The heater cannot then be started until the diagnostic trouble code (DTC) has been erased.

If the combustion preheater module (CPM) registers too low battery voltage or too low fuel level, the heater will be deactivated and a warning message displayed in the driver information module (DIM).

REMOTE START OF PARKING HEATER

Applies from and incl. structure week 201020.

With remote start of the parking heater it is possible to set timers for the parking heater as well as start the parking heater directly via a computer with Internet connection or via mobile telephone.

READING OFF INPUT AND OUTPUT SIGNALS

This function can be used to continuously read off the values and status of the control module's input and output signals.

The following parameters can be read off

1. Engine coolant temperature sensor. The coolant temperature in the heater
2. Overheat protection thermostat. The coolant temperature in the heater
3. Flame sensor. The temperature at the flame sensor
4. Modulation degree glow plugs. Reading off the degree to which the glow plug is activated
5. Fuel pump frequency. Reading off the frequency of the fuel pump
6. Water pump. On: Water pump activated. Off: Water pump deactivated
7. Fuel level, status. Reading off the lowest permitted quantity of fuel to allow the heater to start
8. Lowest permitted battery voltage. Reading off the lowest permitted battery voltage to allow the heater to start
9. Highest permitted battery voltage. Reading off the highest permitted battery voltage to allow the heater to start.

ACTIVATING COMPONENTS AND FUNCTIONS

The components and functions in the engine coolant heater system can be activated using this function.

The following components can be activated

1. Combustion fan. Activating the combustion fan. A "buzzing" sound can be heard from the combustion fan when it is activated CAUTION: Do not activate this function for more than 10-20 seconds.
2. Glow plugs. Activating the glow plug
3. Fuel pump. Activating the fuel pump. A "buzzing" sound can be heard from the fuel pump when it is activated
4. Water pump. Activating water pump. A "buzzing" sound can be heard from the water pump when it is activated
5. Heater. Activating the heater procedure.

Note. The ignition must be on for activation to occur.

REPLACING THE CONTROL MODULE

New software can be downloaded into the combustion preheater module (CPM). When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK the software is downloaded to the control module.

If the comparison between the car and Volvo central database is not OK, the database is updated with the car configuration. When this is complete the software is downloaded.

The controller area network (CAN) is used for a total software reload.

ADD ACCESSORIES

The following accessories can be ordered to add functions

1. engine coolant heater
2. parking heater
3. upgrading to the parking heater from the engine coolant heater.

The vehicle configuration can be read off to check which functions the car is equipped with. Use VIDA (Volvo scan tool). The following affect the function of the heater

1. parking heater or not
2. remote start.

Scheme 651

The driver sets the desired departure time using one of the two timer functions in the display on the driver information module (DIM) (5/1). The time is programmed by twisting the ring on the control stalk and by pressing the SET button for the desired time (timer 1, timer 2 or direct start).

If the engine has not run since the last timer controlled start of the heater, the combustion preheater module (CPM) (4/7) will not permit the heater to be started again until the engine has been started.

The central electronic module (CEM) (4/56) receives information about the desired departure time from the steering wheel module (SWM) (3/254) and the driver information module (DIM).

Approximately 50 minutes before the desired departure time, the central electronic module (CEM) transmits information to the combustion preheater module (CPM) about

1. outside temperature
2. quantity of fuel
3. the operating status of the vehicle
4. a request to calculate the start time of the heater.

The combustion preheater module (CPM) calculates the start time, based on information from the central electronic module (CEM), and starts the heater at the calculated time. The heater calculates when start is required (15-50 minutes before the intended departure at temperatures between -10 °C and +15 °C).

The run time of the heater is a maximum of 60 minutes at temperatures lower than -10 °C.

The running time of the heater is at least 15 minutes before the planned departure (temperatures between +15 °C and +25 °C).

When the heater is started directly using the control stalk, it runs until it is shut off or for a maximum of 60 minutes. The heater remains activated for 10 minutes after the set time to allow for the driver getting to the car late. A text message is displayed in the driver information module (DIM) when the heater is running.

Applies from and incl. structure week 201020.

With remote start of the parking heater it is possible to set timers for the parking heater as well as start the parking heater directly via a computer with Internet connection or via mobile telephone.

ENGINE COOLANT HEATER AND PARKING HEATER

If the parking heater has been programmed and the driver comes to the car earlier than anticipated, the engine coolant heater will engage when the car is started. The engine coolant heater determines whether the heater must be activated or not if the driver does not deactivate the function using the ring on the control stalk in the steering wheel module (SWM) (3/254).

Scheme 652

The primary task of the combustion preheater module (CPM) is to manage the functions for

1. engine coolant heater
2. parking heater
3. remote start
4. remote start of parking heater via Phone module (PHM) (option, from and incl. structure week 201020)

The electrical engine block heater is managed by the accessory electronic module (AEM).

The same control module is used for both the engine coolant heater and the parking heater. Depending on the vehicle configuration, the heater can function as an engine coolant heater or as a parking heater. The heater, which uses radiant heat, is not capable of maintaining a comfortable passenger compartment temperature.

The combustion preheater module (CPM) is positioned on the right-hand side of the engine compartment.

The combustion preheater module (CPM) communicates both with directly connected components and with other control modules via CAN communication.

The control module checks activations that are made, and the input and output signals through integrated diagnostics. A diagnostic trouble code is generated if the control module detects a fault. Any diagnostic trouble codes are stored in the control module memory. The information can be read off using VIDA (Volvo scan tool).

A simple way to check that the combustion preheater module (CPM) is supplied with power is to activate the heater. Listen if the heater starts. It can be activated using

1. the control stalk on vehicles with a parking heater

SIGNALS

The table below summarizes the input signals to and output signals from the combustion preheater module (CPM). The illustration below (Scheme 653) displays the same information with the Volvo component designations.

Scheme 653

Scheme 654

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 is linked to the dashboard dimmer system. The lighting strength is controlled along with the dashboard dimmer function.

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 which is used to

1. set the magnetic zone in which the car is being driven
2. calibrate the compass.

Scheme 655

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.

Scheme 656

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.

The compass must be calibrated when

1. the display does not show a compass direction within a couple of seconds. This may be due to a highly magnetic object being placed in the vicinity of the compass, such as an antenna
2. the compass does not display the correct direction, even though the correct magnetic zone has been set.

The compass has two different calibration statuses

1. initial calibration status
2. continuous calibration status.

On delivery from the manufacturer, the compass is in initial calibration status. The compass can also switch to initial calibration status if it is affected by a strong magnetic field. In this status, the character C appears in the display.

When the character C does not appear in the display, the compass is in continuous calibration status. The initial calibration is concluded and the compass now only performs fine adjustments to the calibration.

In continuous calibration status

1. the compass direction is calculated every 2 seconds, as long as the compass is not affected by a strong magnetic field
2. the compass calibrates itself continually during normal driving
3. if the vehicle is driven across a magnetic zone limit, the compass adjusts itself
4. the compass compensates automatically for slow changes in the vehicle magnetism, which occur as the car gets older
5. the compass detects and corrects itself for dramatic changes in the vehicle magnetism, for example when a magnetic antenna is installed near the compass
6. the display is cleared if the compass detects a very strong magnetic field.

Scheme 657

The compass detects the magnetic pull of the North and South Poles. Using this, the compass calculates the direction in which the front of the vehicle is pointing.

The display in the rearview mirror's upper right corner shows compass direction. Eight different directions can be shown using the English abbreviations and.

1. North
2. Northeast
3. East
4. Southeast
5. South
6. Southwest
7. West
8. Northwest

THE DOOR LOCK

The passenger door module (PDM) and driver door module (DDM) have diagnostics for the front door lock units.

Scheme 658

The power window on the driver's side is operated via the control panel in the driver's door. The power window on the passenger side is operated either via the control panel in the passenger door or via the control panel in the driver's door.

The window lift mechanisms can be operated when the ignition key is in position I or II. The windows can also be operated from when the ignition is switched off until one of the front doors is opened.

The control panel in the driver's door has four spring-loaded switches that operate the individual windows.

The control panel in the passenger door has a spring-loaded switch for operating the window in the door.

The control panels in the left rear door and right rear door, each have a spring loaded switch to operate the relevant power window.

The switches for the window lift mechanisms in all doors have five positions which control the position of the window

0) Normal position where the function is passive.

1) step 1 upwards, raises the window for as long as the button is activated.

2) step 2 upwards, automatically fully closes the window (AUTO-UP).

1) step 1 downwards, lowers the window for as long as the button is activated.

2) step 2 downwards, fully opens the window automatically (AUTO-DOWN).

The rear window lift mechanisms can be switched off using a child lock switch in the control panel in the driver's door. When the child lock is activated, the rear windows cannot be operated from the rear seats. However, the rear windows can still be operated from the control panel in the driver's door (does not apply to the C30 or C70).

In the C70 the control panel in the driver's door is equipped with a button, which operates all windows up or down.

This switch has three positions that control

1. Normal position where the function is passive.
2. Down, automatically operates all windows down (AUTO-DOWN).
3. UP, operates all windows up as long as the button is held in.

The window lift mechanisms have a hall sensor which measures the rotation speed of each lift mechanism, allowing the mechanisms to determine the position of the window. If a Hall sensor is not functioning in one of the window lift mechanisms, the AUTO-UP or AUTO-DOWN function for that window is not available.

In all the doors the power window lift mechanism, power window lift motor and Hall sensor and control module form one unit and cannot be replaced separately.

All power window lift mechanisms in the front doors have an integrated function to prevent pinching.

For C70, only the front windows have crushing protection.

When AUTO UP is activated, the power window detects if it meets resistance, that is to say if too great a force must be used to close the window. The window then stops and goes down a bit. Pinch protection is active during AUTO UP if the window is open more than 3 mm (0.1 in).

A diagnostic trouble code (DTC) is stored if for any reason the power window mechanism is unable to determine the window position. If this should happen, the power window mechanism must be re-initialized. This is carried out via a diagnostic function in VIDA (Volvo scan tool).

The passenger door module (PDM) and driver door module (DDM) have diagnostics for the window lift mechanisms and Hall sensors in the front doors.

The rear window lift mechanisms and Hall sensors can be diagnosed via the control modules in the front doors on the relevant side of the vehicle (does not apply to the C30).

Scheme 659

Motors

The door mirror motors are operated via the control panel in the driver's door.

The mirrors can be adjusted in the X and Y axes via the two motors for each mirror. Two buttons on the control panel, marked L and R, are used to select either the right or left-hand mirror for adjustment. An LED lights in the button that is activated. Only one button can be activated at any one time (left or right). X and Y axis adjustment is made using a control which maneuvers the mirror in the selected direction for as long as the button is pressed (or until the mirror reaches a limit position). To deactivate the adjustment control, press the left or right button again so that the LEDs are off. The mirrors can be adjusted when the ignition key is in position I or II.

The power seat with memory function for door mirrors is optional equipment (only C70).

The function requires that the mirrors' position is saved when the vehicle is locked. Two sensors in each mirror keep track of the mirror position in X-range and in Y-range.

The door windows can be equipped as an option with a motor that allows the mirror housing to be folded in. The motor for folding in the door mirrors is diagnosed and powered by the driver door module (DDM) and passenger door module (PDM) respectively.

The motors and sensors used to set the position of the door mirrors form one unit and cannot be replaced separately.

Heating

The door mirrors contain a heating loop to defrost the glass. The heating loop is on the reverse of the mirror glass. In the event of a fault, the entire mirror glass must be replaced. The heating loops are supplied with power and ground by the driver door module (DDM) and passenger door module (PDM), which also have diagnostics for the loops. However the function is activated by the climate control module (CCM).

Lights in the door mirrors

The door mirrors can be equipped with lamps. The lamps are mounted on the underneath of the mirror housing. The driver door module (DDM) and passenger door module (PDM) have diagnostics for the outputs for the lamps. However the function is activated by the central electronic module (CEM) and the remote control.

Outside temperature

In the left mirror there is a temperature sensor which measures the outside temperature. The temperature information is used by the driver information module (DIM). The temperature sensor is directly connected to the central electronic module (CEM).

The temperature sensor in the left mirror housing can be replaced separately. The temperature sensor is diagnosed via the central electronic module (CEM).

Turn signal lamps

Each door mirror housing has a turn signal mounted at the end of the mirror housing. The driver door module (DDM) and passenger door module (PDM) have diagnostics for the outputs for turn signal lamps.

However, the function is activated via the left control stalk. A signal is transmitted by the steering wheel module (SWM) to the driver door module (DDM) respectively passenger door module (PDM), via the central electronic module (CEM).

Scheme 660

The blind spot information system (BLIS) is an auxiliary system designed to help the vehicle's driver when moving sideways. The blind spot information system (BLIS) consists of two cameras integrated in the external rear view mirrors and two LEDs located in the panel at the front of the inside of the respective windows.

The driver door module (DDM) and passenger door module (PDM) communicate with the left camera module (LCM) and right camera module (RCM) via LIN communication.

The blind spot information system (BLIS) is always activated automatically at speeds over 10 km/h (6 mph). The blind spot information system (BLIS) can be deactivated and reactivated using the switches on the comfort panel of the climate control module (CCM). A signal is then sent via the driver door module (DDM) and passenger door module (PDM) to the left camera module (LCM) and right camera module (RCM) with a request to deactivate or reactivate the blind spot information system (BLIS).

When reverse gear is engaged, the blind spot information system (BLIS) is deactivated.

The system reacts to vehicles in the blind spot if

1. the vehicle is traveling past another vehicle with a speed difference of up to 10 km/h
2. another vehicle passes with a speed difference of up to 70 km/h.

The blind spot information system (BLIS) can be diagnosed.

READING OFF PARAMETER VALUES

With this function, the values and status of parameters can be read from the driver door module (DDM) and passenger door module (PDM).

ACTIVATING COMPONENTS/FUNCTIONS

This function makes it possible to activate components/functions in the driver door module (DDM) and passenger door module (PDM).

READING OFF AND PROGRAMMING DATA

With this option it is possible to read programmed data and to program in data.

Note. If the control module has been replaced, the position of the windows must be initiated using a diagnostic function. A window must be in its uppermost position before it can be initiated.

No customer related programming is available in the control module.

DOWNLOADING SOFTWARE AND REPLACING THE CONTROL MODULE

New software can be downloaded into the passenger door module (PDM) and the driver door module (DDM). When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK the software is downloaded to the control module.

If the comparison between the car and Volvo central database is not OK, the database is updated with the car configuration. When this is complete the software is downloaded.

The window positions must be initialized again after replacing the control module. This is so that the new control module stores the closed position of the window. Initialization is carried out using the diagnostic tool.

If the vehicle is equipped with power seat with memory function for external rear-view mirrors (only C70), this function can be turned off.

This means that it is possible to deactivate personal setting of external rear-view mirrors depending on which remote control unlocks the vehicle.

Deactivation is performed with the diagnostics tool.

After deactivation, this setting will be stored in the control module, but not in Volvo's central database. This means that deactivation must be performed again when a new hardware replacement is carried out.

Scheme 661

Operating the window from the driver's seat

The window is operated by the switch in the control panel (3/81). The motor for the power window on the driver's side is controlled directly from the driver door module (DDM) (3/126). The motor for the power window on the passenger side is controlled via controller area network (CAN) communication from the driver door module (DDM) to the passenger door module (PDM) (3/127).

The signals for operating the rear window on the driver's side are transmitted from the driver door module (DDM) to the rear window using LIN-communication (does not apply to the C30).

The signals for operating the rear window on the passenger side are transmitted from the driver door module (DDM) via the controller area network (CAN) to the passenger door module (PDM) and then to the rear window using LIN-communication (does not apply to the C30).

Operating the front window on the passenger side

The passenger door module (PDM) (3/127) only operates the front window on the passenger side. The window is operated by the switch in the control panel (3/83). The signal is sent via the passenger door module (PDM) to the power window motor on the passenger side.

Operating all windows simultaneously (only applies to the C70, not to the C70 AME with structure week 200820 or later)

On the control panel for the C70 there is a button for operating all windows up or down.

This switch has three positions that control

1. Normal position where the function is passive.
2. Down, automatically operates all windows down (AUTO-DOWN).
3. UP, operates all windows up as long as the button is held in.

FUNCTIONS IN THE DOOR MIRRORS

The functions in the door mirrors (6/62 left) (6/63 right) are controlled from the control panels for the driver door module (DDM) (3/126) or passenger door module (PDM) (3/127) are

1. setting the mirror position
2. folding in the door mirrors
3. heating the mirrors
4. approach lighting/guide lighting
5. indicators.

The left door mirror has a temperature sensor for the outside temperature. The signal from the temperature sensor is directly connected to the central electronic module (CEM). The signal is not controlled by the driver door module (DDM) or the passenger door module (PDM).

Setting the mirror position

Scheme 662

The position of the mirror is controlled using buttons on the control panel on the driver's side (3/81). The driver door module (DDM) (3/126) transmits a signal directly to the mirror on the driver's side (6/62). When adjusting the mirror on the passenger side (6/63), a signal is transmitted via the driver door module (DDM) to the passenger door module (PDM) (3/127) on the controller area network (CAN). The passenger door module (PDM) transmits the signal to the door mirror.

Memory function (Only C70)

If the vehicle is equipped with a power seat with memory function for external rear view mirrors, mirror position is stored by two potentiometers.

Signal about position in X-direction and Y-direction is received by Driver door module (DDM) and Passenger door module (PDM), respectively.

When one of the buttons on the control unit for the power driver seat is activated, a signal is sent from Power seat module, left (PSL) (3/26) to Driver door module (DDM) and Passenger door module (PDM), respectively.

These set the external rear view mirrors in stored position. Stored position can also be set depending on which remote control unlocks the vehicle.

Folding in the door mirrors

The mirror is folded by holding the L and R buttons on the control panel (3/81) on the driver's side. A signal is transmitted via the driver door module (DDM) (3/126) to the passenger door module (PDM) (3/127) via the controller area network (CAN). The control modules send the signal on to each door mirror (6/62 and 6/63), which fold each mirror in or out.

Heating the mirrors

Scheme 663

Mirror heating is activated at the same time as rear window heating (there is no rear window heating on the C70). When the switch for heated rear window/ door mirrors is pressed the climate control module (CCM) (3/112) activates rear window heating. At the same time the signal is sent via the controller area network (CAN) to the driver door module (DDM) (3/126) and the passenger door module (PDM) (3/127) to activate the door mirror heating. When the Driver door module (DDM) respectively, Passenger door module (PDM) receive the signal, the outputs for each door mirror are powered (6/62 and 6/63). The function is switched off at the same time as the rear window defrosting. This can happen in three different ways

1. If the switch for heated rear window/door mirrors is pressed again after activation, the function is switched off, using a signal from the climate control module (CCM).
2. The heating switches off automatically 12 minutes after activation. The driver door module (DDM) and the passenger door module (PDM) receive a signal from the climate control module (CCM) which requests that the function is activated
3. The heating is also switched off if the ignition is switched off.

Approach lighting/Guide lighting

Scheme 664

The approach lighting is activated using the remote control for the vehicle. The function can only be activated when the ignition is off. When the yellow button on the remote control is pressed, the central electronic module (CEM) (4/56) receives an activation signal which is sent onwards on the controller area network (CAN). The driver door module (DDM) (3/126) and passenger door module (PDM) (3/127) receive the signal and switch on the lighting for the left door mirror (6/62) and the lighting for the right door mirror (6/63). The function is deactivated by pressing the button on the remote control again. A signal is then sent from the central electronic module (CEM) to the driver door module (DDM) and passenger door module (PDM) requesting that the function is switched off. The function is also switched off when the ignition is switched on.

The guide lighting is activated using the left control stalk (the key must be removed from the ignition switch). Steering wheel module (SWM) (3/254) transmits a signal via the controller area network (CAN) to the central electronic module (CEM). When the car is then locked, the central electronic module (CEM) sends a signal onwards via the controller area network (CAN) to the driver door module (DDM) and passenger door module (PDM), which turn on the lights in the door mirrors. The lights are part of the guide lighting function and remain on for a set time (30, 60 or 90 seconds).

Measuring the outside temperature

Scheme 665

The left door mirror has a temperature sensor for the outside temperature. The signal from the temperature sensor is directly connected to the central electronic module (CEM). The signal is not controlled by the driver door module (DDM) or the passenger door module (PDM).

Indicators

SHORT-DROP

During operation of the roof, all side windows lower at least 80 mm to prevent friction between the roof unit and the windows. A signal is transmitted from the Convertible Roof Module (CRM) via the CAN network to the Driver door module (DDM) and the Passenger door module (PDM). These send a signal on via LIN to the Left rear door module (LDM) and Right rear door module (RDM). When the door are opened the window lowers 4 mm to prevent wearing the roof's rubber weatherstrip. After the door has been closed the window goes up behind the rubber weatherstrip to prevent leakage.

Scheme 666

The illustration shows the area within which the Blind Spot Information System (BLIS) detects.

A: approximately 9.5 meters.

B: approximately 3 meters.

Scheme 667

The cameras take 30 images per second and compare each image with the previous one to check for changes. To determine if any changes are significant, the camera module must also know the vehicle speed. To calculate the vehicle speed and know if the vehicle is turning, the speed signals for each rear wheel are used from the Brake control module (BCM). The driver door module (DDM) (3/126) and passenger door module (PDM) (3/127) receive information from the Brake control module (BCM) (4/16), via CAN, about the speed of both rear wheels. Both these signals are then transmitted to the Left Camera Module (LCM) (6/62) and the Right Camera Module (RCM) (6/63) via LIN communication.

If the camera module discovers that there is something in the dead angle, an orange LED, located on the inside of the panel at the front of the window on the door, comes on. This LED is directly connected to the respective camera module.

In daylight the system reacts to the shapes of surrounding vehicles. The system is designed to detect cars, trucks motorcycles and buses. In darkness the system reacts to the light from the headlamps of other vehicles. If the headlamps of surrounding vehicles are not switched on then the Blind Spot Information System (BLIS) will not detect the vehicle.

The system detects sharp contours. Light reflections and shadows can generate warnings because the system cannot distinguish them from real objects.

Weather conditions that may generate false warnings are

1. Reflections from a wet road surface.
2. Low sun shining into the camera.
3. The vehicle's own shadow on large bright surfaces.

Blind Spot Information System (BLIS) is activated when the ignition is on. The system cannot be deactivated but the function to light the light-emitting diodes and to show text messages can be disconnected with the switch on the comfort panel. The function can be reconnected with the switch.

When the switch is activated, a signal is sent from Climate control module (CCM) (4/6) to Driver door module (DDM) and Passenger door module (PDM) via the CAN-net.

A diagnostic trouble code (DTC) is stored if a fault is detected by the Driver door module (DDM) and Passenger door module (PDM) and a signal is transmitted via CAN to the Driver information module (DIM) (5/1), which lights the general warning lamp and displays a text message.

FRONT DOOR CONTROL MODULES

The driver door module (DDM) and the passenger door module (PDM) are broadly similar in terms of functionality. Both these control modules are described in common in this document. In those cases the differences between the driver door module (DDM) and the passenger door module (PDM) are given. The main task of both control modules is to manage

1. the power window mechanism
2. the door lock
3. door mirror adjustment
4. door mirror folding
5. door mirror heating
6. approach lighting
7. turn signals in the door mirrors
8. Blind spot information system (BLIS)

The control modules are in their respective doors. The driver door module (DDM) is on the driver's side. The passenger door module (PDM) is on the passenger side. The control modules are integrated with the power window lift motors. The control modules must also be replaced when replacing the power window lift motors.

The driver door module (DDM) and passenger door module (PDM) communicate with directly connected components and with other control modules and components connected via CAN communication.

The driver door module (DDM) communicates with the control panel in the driver's door via LIN communication.

The Driver door module (DDM) and Passenger door module (PDM) communicate with the control module for the rear doors on its respective side of the vehicle via LIN communication (does not apply to the C30).

Both control modules check activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if either of the control module detects a fault.

The diagnostic trouble codes (DTCs) for the control modules in the rear doors are stored in the respective control module in the front doors (does not apply to the C30).

Any diagnostic trouble codes (DTCs) are stored in the relevant control module memory. The data can be read off.

A simple way to ensure that the control modules are powered and grounded is to activate one of the functions that are operated via the switches on the control panels in the respective door. The control module is powered and grounded if any of the functions are working.

For further information, see SIGNALS .

Scheme 668

Left rear door module (LDM) and Right rear door module (RDM) are completely the same and only manage the functions for power windows and door locks in their respective door (door locks do not apply to C70).

The control modules are positioned in their respective doors (in the C70 they are located under the respective rear side window). The control modules are integrated with the power window lift motors. The control modules must also be replaced when replacing the power window lift motors.

There is only one version of control module.

The difference between the versions is that Standard does not have deadlocks or child safety lock.

The left rear door module (LDM) and right rear door module (RDM) communicate with directly connected components and with the control module for the front door on the relevant side of the vehicle via LIN-communication.

Both control modules check activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if either of the control module detects a fault. The diagnostic trouble codes (DTCs) for the control modules in the rear doors are stored in the respective control module in the front doors.

Any diagnostic trouble codes (DTCs) are stored in the relevant control module in the front doors. The data can be read off.

A simple way to ensure that the control modules are powered and grounded is to activate one of the functions that are operated via the switches on the control panels in the respective door. The control module is powered and grounded if any of the functions are working.

For further information, see SIGNALS .

The table below summarizes the input signals to and output signals from the driver door module (DDM) and passenger door module (PDM). The signal types are divided into directly connected signals, LIN and CAN communication. The illustration below (Scheme 669) displays the same information with the Volvo component designations.

Scheme 669

Scheme 670

The switches for operating the roof are located on the transmission tunnel in the passenger compartment.

The switches are directly connected to the Convertible Roof Module (CRM). The Convertible Roof Module (CRM) receives signals from the switches to start roof operation after all necessary checks are made.

When operating the roof for opening/closing, the switch must be held depressed so that the roof opens/closes.

The functions of the switches

1. open the roof
2. close the roof.

Scheme 671

The switch for load assistance is located on the right-hand side on the sill in the cargo compartment and is directly connected to the Convertible Roof Module (CRM). The switch controls a function called load assistance.

For operation, press the switch

1. once to activate movement
2. once more to stop (if the limit position has not already been reached)
3. a final time to reset the roof sections.

Operation is automatic and the switch must not be held depressed.

Functions of the load assistance switch

1. to raise the stored roof sections
2. to lower the stored roof sections
3. to stop operation of the load assistance.

Scheme 672

There are three types of sensors that are directly connected to the Convertible Roof Module (CRM); Hall sensors, position sensors and the temperature sensor. The task of the hall sensors and position sensors is to inform the Convertible Roof Module (CRM) about the position of the roof. Information about the temperature sensor can be found in HYDRAULIC PUMP . There are also a number of mechanical catches that lock the roof in certain positions.

From the signals of the sensors the Convertible Roof Module (CRM) interrupts the movement of the roof when there is a risk of passing the limit position or when the roof module risks damaging parts of the vehicle.

Hall sensors

Scheme 673

There are 14 Hall sensors installed around the roof for the roof function in the vehicle.

The task of the Hall sensors is to supply the Convertible Roof Module (CRM) with information about the position of the roof. The Hall sensors are directly connected to the Convertible Roof Module (CRM). The Hall sensor, which is a magnetic sensor, reads off if a certain part of the roof passes a sensor. This means the Convertible Roof Module (CRM) can determine the position of the roof, depending on which sensor has been passed.

Position sensors

Scheme 674

There are two position sensors for the roof function in the vehicle. The sensors are mounted on the left-hand side in the link system. One by the link system for the roof's rear section and the other by the link system for the front roof section. The sensors read off the angle of the link system at operation. The signal is used by the Convertible Roof Module (CRM) to determine when the next phase of movement should occur.

HYDRAULIC CYLINDERS

There are 11 hydraulic cylinders In the vehicle that are controlled by the hydraulic pump to move the roof sections when opening and closing. They manage different functions for the roof individually and in pairs.

Scheme 675

The hydraulic pump is mounted under a bracket in the cargo compartment below the ski hatch. The pump drives all hydraulic cylinders for the roof's function. There is a temperature sensor in the hydraulic pump that reads off the operating temperature of the hydraulic pump. The hydraulic pump is partially controlled depending on the temperature in the hydraulic pump (see the uppermost table below).

The roof's functionality also depends on the outside temperature (see the table below).

HYDRAULIC VALVES

The hydraulic system is equipped with 4 hydraulic valves that control the movement of the hydraulic cylinders. The valves are directly connected to the Convertible Roof Module (CRM). The hydraulic valves are integrated in the hydraulic pump unit.

Scheme 676

The electric catch motor is a unit that locks the trunk lid in the correct position. The unit consists of a motor and a spring (a flexible metal cable) that transfers power to the various catches, which, in turn lock the trunk lid. The electric catch motor is directly connected to the Convertible Roof Module (CRM). The electric catch motor is located in the cargo compartment. The electric catch motor also has an integrated position sensor that senses the position of the motor.

READING OFF THE PARAMETER VALUES

Using this function, the status or value of parameters can be read off. The presentation of the status or value can be graphic or digital.

New software can be downloaded into the Convertible Roof Module (CRM). When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database.

If the comparison between the car and Volvo's central database does not correspond, then the database is updated with the vehicle's configuration. When this is complete the software is downloaded.

Calibration of position sensor

Use this option to calibrate the Convertible Roof Module (CRM) to the position of the position sensors. So that the roof sections do not collide during operation, this option must be run after

1. downloading software to the Convertible Roof Module (CRM)
2. replacing the position sensors
3. replacing the entire roof
4. replacing the Convertible Roof Module (CRM).

Scheme 677

The illustration shows which control modules are involved when operating the retractable roof.

Roof operation is activated via the switches on the control panel in the passenger compartment. The switches (3/25) are directly connected to the Convertible Roof Module (CRM) (4/59). The Convertible Roof Module (CRM) then transmits a signal on the CAN network to the Driver door module (DDM) (3/126) and the Passenger door module (PDM) (3/127). These, in turn, transmit another signal via their LIN network to the Left rear door module (LDM) (3/128) and the Right rear door module (RDM) (3/129).

All side windows lower at least 80 mm, to prevent friction between the roof and the windows when the roof is retracted and operated up. Thereafter the hydraulic pump and roof operation starts.

The roof is operated using an electrical and hydraulic system with the following components.

1. Hydraulic cylinders
2. Position sensors, used to determine the position of the hydraulic cylinders.
3. Hall sensors, used to determine the position of the various metal components of the roof.
4. Hydraulic pump
5. Hydraulic valves, used to control the various hydraulic cylinders.
6. Mechanical catches, used to lock parts of the roof in different positions.
7. Electric catch motor, is an electro mechanical unit that is used to transfer mechanical force via a spring to the various catches.

LOAD ASSISTANCE

This function increases the space in the cargo compartment when the roof is retracted and all roof sections are collected in the cargo compartment. This is to facilitate loading cargo. The maximum compartment height is then 300 mm. The cargo compartment divider must always be extended in order for the load assistance function to be activated. The function is checked by the Convertible Roof Module (CRM) and controlled from a switch located in the cargo compartment, on the right-hand side of the sill.

When the load assistance switch is activated, the roof sections start to move to their limit positions.

The switch does not need to be held pressed in for operation.

Every time the switch is activated, the direction of operation is changed. If the switch is pressed before the operation reaches its limit position, the entire operation stops immediately. The next time the switch is activated, the direction changes.

The following sequence is followed when the switch is activated: Up-Stop-Down-Stop-Up-Stop- etc.

DIVIDER CARGO COMPARTMENT

The cargo compartment is divided into two sections by a divider. The compartment above the divider houses the roof components. The compartment beneath is always available for luggage. The divider must always be extended in order for the load assistance function to work. In order for the Convertible Roof Module (CRM) to know whether the divider is extended and connected, a Hall sensor is located there to read off the position.

To prevent interference between roof sections and windows, all side windows are lowered 80 mm from their uppermost positions (completely closed) when operating the roof. This function is known as short-drop.

The function is also used when opening and closing the doors. The windows are lowered or raised by 4 mm so that they are inside the rubber trim when the doors are closed

The Passenger door module (PDM), Driver door module (DDM), Left rear door module (LDM) and Right rear door module (RDM) receive a message from the Convertible Roof Module (CRM) via the CAN network to start a short-drop at roof operation.

If the window is already in a lower position than the short-drop position, this function is ignored. During the time that short-drop is active, all other window operations are disengaged.

DEACTIVATING THE DEFROST FOR THE REAR WINDOW

When the roof is completely open and folded up in the cargo compartment, the defroster is deactivated and the power of the blower fan are reduced. The Climate control module (CCM) checks this function on command from the Convertible Roof Module (CRM) via a message on the CAN network.

SPEED RESTRICTION

The roof can only be operated when the vehicle is traveling at speeds below 2 km/h.

If the speed exceeds 2 km/h during the time the roof is being operated, the entire operation stops and a warning sound signal starts from the Driver information module (DIM).

The signal for the vehicle's speed is obtained from the Central electronic module (CEM).

TEXT MESSAGE IN THE DRIVER INFORMATION MODULE (DIM)

When the roof is being operated, the driver can see the status of the roof at all times in the form of a text message in the Driver information module (DIM).

SOUND PARAMETERS

The Convertible Roof Module (CRM) transmits the position of the roof out to the CAN network to the Infotainment control module (ICM) so that it can set the necessary sound parameters.

LOW VOLTAGE

When the Central electronic module (CEM) signals a low battery on the CAN network to the Convertible Roof Module (CRM), it is not possible to operate the roof.

HINT: It is possible to close the roof and lower load assistance once in the event of low battery voltage.

The Convertible Roof Module (CRM) also measures the voltage internally to prevent operating the roof when voltage is low.

LOCKABLE STORAGE COMPARTMENTS AND SKI HATCH (OPTIONAL)

Note. Lockable storage compartments and lockable ski hatch are discontinued as an option from and incl. structure week 200946 (USA and Canada) and 201020 (other markets).

Lockable storage compartments and ski hatch are available as options. When the vehicle is locked, so are the storage compartments and ski hatch. The storage compartments and ski hatch are each locked with an electric motor. The electric motors for the lockable storage compartments are located one in each door. The electric motor for the lockable ski hatch is located in the backseat's backrest. The motors are connected in parallel and are activated when one of the connections on Convertible Roof Module (CRM) is supplied with voltage. To change locking for unlocking, the polarity is reversed on the output connections in the control module. These electric motors cannot be diagnosed and the driver is not given any indication if any one of these electric motors is faulty.

Scheme 678

The Convertible Roof Module (CRM) controls the operation of the Power Retractable Hardtop. The control module manages signals for controlling the hydraulic pump and from the sensors around the roof as well as the functions that can be controlled via the switches.

The control module is connected to CAN LS (Low speed, 125 kbit/s).

The Convertible Roof Module (CRM) is responsible for

1. Monitoring the sensors to be able to check operation of the roof and the load assistance functionality.
2. Activating the opening/closing sequence for the roof and load assistance by checking the electric and hydraulic systems.
3. Communication with other control modules via the CAN network to control windows via the door control modules, to prevent friction and other problems between the roof sections and windows during the time the roof is operated. The Convertible Roof Module (CRM) is also responsible for deactivating the automatic climate position via the Climate control module (CCM) when the roof is open and to automatically adjust the sound settings in the Infotainment control module (ICM).
4. To check the warning conditions, for example, too high a speed, internal faults etc. and to warn the driver through the Driver information module (DIM)
5. Locking/unlocking the lockable compartments and the ski hatch lock.

The control module is located in the cargo compartment on the right-hand side behind the panel.

The Convertible Roof Module (CRM) communicates with directly connected components and with other control modules via CAN communication.

The control module checks activations and input and output signals using an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if the control module detects an error. In certain cases the control module replaces the faulty signal with a substitute value.

Diagnostic trouble codes (DTCs) can be stored when the key is in position 0, 1, 2 or 3.

Any diagnostic trouble codes are stored in the control module memory. The information can be read out via the data link connector in the vehicle.

A simple way to ensure that the Convertible Roof Module (CRM) is powered and grounded is to activate one of its functions, for example, operate the roof using its switch.

This service information only deals with the control module and its corresponding components.

The table below covers input and output signals to and from the Convertible Roof Module (CRM). The signal type is split into directly connected signals and CAN communication. The illustration below (Scheme 679) provides the same information with Volvo's component designations.

Note. Lockable storage compartments and lockable ski hatch are discontinued as an option from and incl. structure week 200946 (USA and Canada) and 201020 (other markets).

Scheme 679

BACKGROUND

Factors that have improved safety, increased comfort, added functions and increased environmental friendliness, have made modern vehicles more and more complicated.

The more complicated the vehicle is, the more important is the diagnostics system in the vehicle with the diagnostics tool when it comes to ensuring fast, safe and economic test, service and repair.

To reduce emissions from the vehicle, the diagnostic systems shall also, according to legislation, detect emission-influencing problems as well as defects that may cause follow-up damage on emission-related components.

LEGAL REQUIREMENTS EMISSIONS

OBD I - On Board Diagnostic I

On Board Diagnostic I (diagnostic system in the vehicle) was 1988 a requirement from CARB (California Air Resource Board) which is an air quality board. The purpose of these regulations was to ensure that component or function defects that affected exhaust emissions are detected by the control module's diagnostic functions.

OBD I included diagnosis of control module, emission-related components connected to the control module as well as exhaust gas recirculation.

Using the diagnostic socket in the engine compartment, the information about the system was accessible to all, both brand-name workshops and independent workshops.

In case of a detected emission-related problem, a warning light is activated in the driver information module (MIL= Malfunction Indicator Light), when the problem is confirmed as a real malfunction. Thus, the light is not activated immediately upon detection, only first when the malfunction is confirmed, which may be, e. g., following a few driving cycles.

OBD II - On Board Diagnostic II

Scheme 680

On Board Diagnostic II was another requirement from CARB that applied from 1996. CARB demanded additional and refined diagnosis for emission-related component and systems in the drivetrain (engine and transmission).

Also, a standardized communication method was required for reading out of diagnosis (Standard SAE J1979 and J2190, where J2190 is voluntary and includes Enhanced Diagnostics - the vehicle manufacturer's own diagnosis in addition to legal requirements).

It should be possible to read out diagnostic trouble codes and their format, information connected to diagnostic trouble codes as well as parameters*, according to this standard. OBD II's diagnostic trouble codes are five-digit and begin with the letter P followed by four digits.

This standardized communication method means that anyone shall be able to manufacture and sell an instrument for reading out, a so-called Generic Scan Tool. Thus, the vehicle owner is not dependent on using a brand-name workshop.

The standard OBD II requires a standardized diagnostic socket in the passenger compartment near the driver's seat, where this instrument is to be plugged in. This means that the diagnostic socket (connector) is the same on all vehicles regardless of manufacturer or model.

However, there is a difference between manufacturers regarding which pins are used in the connector. This depends on the OBD II standard supports four types of communication protocols.

A protocol may be said to be the "language" that is to be used for communication with the control module.

Scheme 681

Standardized pins on OBD II-connector

1. Pin 2 SAE J-1850 bus +
2. Pin 4 Chassis ground
3. Pin 5 Signal ground
4. Pin 6 SAE J-2284, CAN-bus (CAN-H)
5. Pin 7 SAE J1979, ISO 9141-2 / ISO14230-4, K-line
6. Pin 10 SAE J-1850 bus
7. Pin 14 SAE J.2284, CAN-bus (CAN-L)
8. Pin 15 ISO 9141-2 / ISO14230-4, L-line
9. Pin 16 Voltage feed

Other pins in the connector are permitted for the vehicle manufacturer's own specific use. On pin 7 (K-line), two-way communication is permitted, on pin 15 (L-line) only one-way communication is permitted to the control module. Therefore, the L-line is missing in many vehicles.

ISO14230-4 = Protocol KWP2000.

OBD II was first introduced for Volvo on engine management system Motronic 4.3, Motronic 4.4, and automatic transmission AW 50 42, AW 30 40/43 in model 850/960..

With time, OBD II-communication with control modules via CAN is introduced.

The legal requirement also includes the function Readiness Monitoring.

* Parameter refers to, e. g., RPM, engine temperature, battery voltage, etc., with associated value 800 RPM, 87 °C as well as 14, 2 V, etc.

NON-STANDARDIZED SERIAL COMMUNICATION

As a supplement to Volvo Diagnostics - first and second version, the supplier of engine management systems developed their own diagnostic and communication methods (On Board Diagnostic). These were introduced during 1991/92 .

These serial* communication methods were supplier-specific and varied a lot between systems. To communicate quickly and directly with control modules was a pre-condition for developing the control system and opened for new possibilities.

The access to more information about the detected problem as well as the possibility to, e. g., quickly read out parameters, enabled improvement of troubleshooting methods. Therefore, these communication methods were used by the workshops' diagnostics tools.

The cable in the vehicle used for this serial communication is connected to the diagnostic socket in the engine compartment and is the same one used for Volvo Diagnostics, first and second version.

Included functions are, among others

1. Reading out and erasing diagnostic trouble codes.
2. Reading off frozen values.
3. Reading off values of signals such as coolant temperature, voltage on heated oxygen sensor, etc.
4. Activating components and functions.
5. Programming of customer parameters and functions.
6. Calibration of functions.
7. Resetting of adaptations.

The tool Volvo System Tester was developed to make communication easier with the control module.

Non-standardized serial communication was introduced on engine management system Motronic 1.8 in model 960 and engine management system Fenix 5.2, Motronic 4.3, and LH3.2/EZ129K in model 850.

* Serial means that the information is sent as a series of signals in the form pulse trains (= series of pulses) via a cable between the tool and control module.

PARAMETERS

Parameters or values are data that are read out from the control module's memory positions to, e. g., check the signal from a sensor or identify the control module's software version.

In principle, parameters can be divided into two parts

1. one for dynamic values continuously updated in the control module
2. one for static values not changed by the control module and always stored.

Parameters, dynamic

Scheme 682

The dynamic values are stored in the control module's RAM-memory, which means that the values disappear when the memory's power supply is turned off (control module is turned off). As soon as the control module's power is turned on (ignition on), values are stored again.

Example of values are

1. Outside temperature
2. Engine speed
3. Load
4. Coolant temperature
5. Vehicle speed
6. Battery voltage

Values are updated continuously after a pre-determined time interval. This means that certain values are updated with very short time interval, while other values are updated more seldom. Update rate is determined by how important the value is to the control module.

By reading off the value from, e. g., a sensor or switch, it can be decided if the signal is correct or not.

Note. When a malfunction is detected and a diagnostic trouble code is stored, it may well be that the displayed value is a replacement value and not the real value. If the value does not change, e. g., if the sensor is disconnected, it may be the replacement value that is shown.

Parameters, static

Scheme 683

The static values are stored in the control module's EEPROM, which means that these values are always stored regardless of if the control module is on or off. These values are normally not updated by the control module, instead they are only changed using, e. g., the diagnostics tool at vehicle manufacture in the factory or reprogramming during a workshop visit.

Example of values are

1. Hardware P/N (control module without software).
2. Hardware serial number (control module without software).
3. Software P/N.
4. Diagnostic software P/N.
5. Customer-programmed values, e. g., passenger compartment temperature, alarm on and off.
6. The vehicle's configuration, that is, the vehicle's content and equipment that can be used to compare the vehicle's equipment physically with how the vehicle is configured. The configuration may be affected/changed, e. g., when downloading software.

Scheme 684

Wit this service it is possible to trigger (activate) the components that are connected to the control module. Examples of components are

1. Relays
2. Solenoids
3. Lock motors
4. Damper motors
5. Signals to other control modules.

Note. If a malfunction is detected, diagnostic trouble code is stored and emergency functions or modes, etc. are activated to "protect" the system, the control module can prevent activation.

Depending on the system, the control module or diagnostics tool can perform activations in different ways, for some the component is activated according to a certain pattern, e. g., OFF, ON, OFF, ON, OF, ON, etc. in a sequence.

For other systems, the component is activated, e. g., ON, and remain on until the activation is stopped.

SOFTWARE DOWNLOADING

New software can be downloaded to the control modules. When ordering software the vehicle software and hardware are compared to Volvo's central database. If the comparison corresponds the new software is downloaded to the control module.

If the comparison between the car and Volvo's central database does not correspond, then the database is updated with the vehicle's configuration. When this is complete the software is downloaded.

READINESS MONITOR (CERTAIN MARKETS ONLY)

This is a function in Engine control module (ECM) that controls the control module's emission-related sub-system. With the function you can read out if the control module has run all diagnostics for the following sub-systems

1. Misfiring
2. Fuel system
3. Catalytic converter
4. Evaporative emission (EVAP) system
5. Heated oxygen sensors (HO2S)
6. Other related components

Thus, Readiness refers only to if the diagnostics (tests) have been run or not, not if a malfunction was found or not. If a malfunction is found during the test, a diagnostic trouble code is stored and the malfunction light (MIL-light) is lit.

If the tests are run in the driving cycle without detecting a malfunction, then "Readiness" is immediately generated to OK.

However, if a malfunction is found in the driving cycle, then Readiness is generated to Not OK, and another driving cycle is required where the test is run to generate Readiness to OK.

The following alternatives are possible

1. Readiness is run (OK), no malfunction detected, which means that the vehicle can be approved in a check.
2. Readiness is run (OK), with malfunction detected, which means that the vehicle cannot be approved in a check.
3. Readiness is not run (Not OK), which means that the vehicle cannot be approved in a check.

Readiness was originally a requirement from the American authority, United States Environmental Protection Agency (EPA), and is used there for Inspection and maintenance test (IM-test) (corresponds to annual inspection). Depending on legal requirements, the function may also be found on other markets.

EMERGENCY MODE, BACK-UP MODE "LIMP-HOME"

When a malfunction has occurred in the system that is confirmed (permanent malfunction) and is registered by the control module, modes are activated for certain systems and functions to handle the malfunction.

The purpose of these actions is to "protect" the control system and at the same time retain as much functionality or driving function as possible.

The minor malfunctions do not activate any back-up modes, there are different programs depending on type of malfunction and which control system to which it applies. All control systems do not have emergency modes or back-up modes.

Sometimes emergency modes must be activated immediately when a malfunction is detected, even if there has been no time to confirm and store any diagnostic trouble code. This is to maintain certain function, e. g., in case of malfunction of the mass air floe sensor for the engine management system, when the emergency program tries to prevent the engine from stopping.

HINT: Limp-home, emergency mode or back-up mode that may appear in case of malfunction is described in diagnostic trouble code information under replacement values.

For, e. g., automatic transmission TF-80SC AWD (XC90, B8444S) there are two back-up modes

1. Failsafe action (temporary action)
2. Emergency/limp-home mode

Failsafe action is activated at the first detection of the malfunction, if the malfunction disappears the system returns to normal function.

Emergency mode is activated in case of less serious malfunctions Limp-home mode is activated for the most serious malfunctions.

The warning light in the driver information module lights up, and a text message is shown in the text window in the driver information module that emergency/limp-home mode has been activated. When the ignition is turned off and on again, no text is shown until the malfunction is detected again.

Note. If the malfunction disappears (intermittent malfunction) the control module returns to normal function first when the ignition is turned on the next time.

For automatic transmission's emergency mode, the following may take place, e. g.

1. Adaption function is blocked.
2. Lock-up function is blocked.
3. Function slipping lock-up is blocked.
4. Function neutral check is blocked.
5. The transmission only shifts to 3rd gear and reverse gear. All other shifting is blocked.

The above actions will be noticed by the driver since only one gear can be sued. Some may also notice that lock-up is not engaged. Then the vehicle comes to the workshop with a symptom for some form of lost driving function, probably also with the warning light on.

This symptom shall not be confused with the malfunction itself, instead it is a symptom of the back-up mode. The symptom that the malfunction itself causes (it it causes any) may be noticed briefly or not at all.

Note. If the malfunction is confirmed (permanent) it may be that the control module resumes normal function at ignition off and on again (symptom does not exist any longer). First when the malfunction is detected again (diagnostic trouble code test started and conditions fulfilled), the back-up mode is activated. The malfunction may then first be interpreted as if it was intermittent (non-existent or not active).

FROZEN VALUES

For every diagnostic trouble code, pre-defined parameters are frozen and stored in the control module. The frozen values are stored immediately after the malfunction has been detected and gives a "picture" of the conditions when the malfunction was stored.

Note. Status identifier, Counter and Frozen values are the most important factors to deciding the malfunction's nature, that is, to decide

1. when the malfunction was detected (frozen values, counters)
2. what the driving conditions were at the time (frozen values)
3. status for the test (self-diagnosis) (status identifier)
4. how frequent the malfunction is (counter).

In newer car models, frozen values consist of a number of global (common) general parameters as well as a number of control model-unique parameters. Global may be

1. Road distance
2. Battery voltage
3. Passenger compartment temperature
4. Outside temperature
5. Engine running

In addition to these, the diagnostic trouble code-unique parameters are stored which are especially selected parameters for the diagnostic trouble code.

Most parameters in the frozen values are the same for all malfunctions and indicate a general condition when a malfunction was detected, for example

1. Road distance
2. Outside temperature
3. Engine speed
4. Load
5. Coolant temperature
6. Vehicle speed
7. Battery voltage
8. etc.

Some of them have been selected to give a better understanding of the specific malfunction.

Note. When erasing diagnostic trouble codes, stored frozen values are also erased.

HINT: Reading out and interpreting these frozen values make it easier to understand when in time the malfunction occurred, as well as under what driving and environment conditions the malfunction was detected, related to when and how the customer experienced the symptom.

Scheme 685

A malfunction that is detected is assessed by the control module's self-diagnosis. First after, e. g., a certain time, a certain number of driving cycles, certain driving/operation or other conditions, the control module decides if it is a real malfunction or not.

When self-diagnosis has determined that a real malfunction exists, you can say that the malfunction is confirmed and the malfunction is stored in the control module's trouble code memory in the form of diagnostic trouble codes.

If a malfunction disappears, the diagnostic trouble code will remain for a tome in the diagnostic trouble code memory, but the status of the diagnostic trouble code changes. How long the diagnostic trouble code is stored in the diagnostic trouble code memory is different from control module to control module, as well as between different vehicle models (generation of vehicle model).

In some systems the diagnostic trouble code will be stored until it is erased with the diagnostics tool. In other systems the diagnostic trouble code is erased automatically by the control module after, e. g., a certain number of malfunction-free driving cycles. A new driving cycle (operation cycle) is usually started every time the ignition is turned on.

Information about the nature of the malfunction is stored for every diagnostic trouble code

1. when the malfunction was detected (frozen values, counters)
2. what the driving conditions were at the time (frozen values)
3. status for the test (diagnosis) (status identifier)
4. how frequent the malfunction is (counter).

Exactly what is stored is different from control module to control module, as well as between different vehicle models (generation of vehicle model).

If the system is provided with warning light, it is lit when the ignition key is turned to position II. The warning light will go off after a certain number of seconds when no malfunction is detected on the control system.

The warning light will be on in case of a malfunction of the control system. The warning light will be lit first after the malfunction is confirmed as a real malfunction.

COUNTER

For every diagnostic trouble code, the control modules stores a number of counters. These counters count the number of driving cycles that have been performed in the control module with or without malfunctions, if the malfunction is detected or not. In control systems older than model year 1999, there may be control systems, depending on control system, without counters or with few counters. From model year 1999, there are systems with several counters. The following counters may appear

1. Counter 1
2. Counter 2 *
3. Counter 3
4. Counter 4
5. Counter 5**
6. Counter 6
7. Counter 7
8. Counter 8

The text uses the term driving cycle, which may also be called Operation cycle.

* In principle, only systems with the diagnostic concept Generic Global Diagnostic (GGD).

** Only for emission-related systems.

When erasing diagnostic trouble codes, the diagnostic trouble code's counter is erased.

Note. Status identifier, Counter and Frozen values are the most important factors to deciding the malfunction's nature, that is, to decide

1. when the malfunction was detected (frozen values, counters)
2. what the driving conditions were at the time (frozen values)
3. status for the test (self-diagnosis) (status identifier)
4. how frequent the malfunction is (counter).

Scheme 686

Graph A in the illustration shows when in time the malfunction occurs. In the illustrated graph, the control module has detected a malfunction in the second driving cycle (graph's x-axis) and this malfunction then appears 4 more times, a total of 5 times. Counters can be read out for every diagnostic trouble code in the control module which have this introduced. Driving cycles are marked with vertical lines. A driving cycle often begins with ignition on and ends with ignition off.

Counter 1 (C#1). Counts number of cycles performed since the malfunction was confirmed last . As soon as a malfunction is detected and confirmed, the value is reset.

When the malfunction is both detected and disappears in the second driving cycle (graph A in the illustration), counter 1 will count up to 1 first in the following driving cycle (driving cycle 3), that is, a driving cycle has been run through since the last time the malfunction was confirmed.

In driving cycle 4, the counter is updated again, now to value 2. Just after that, the malfunction is detected (graph A in the illustration), the malfunction is confirmed and the counter's value is reset. This sequence is repeated once again in driving cycle 5.

With other words, one can say that if the value is zero, the malfunction exists now or has existed earlier in the current driving cycle. If the vehicle is restarted so that a new driving cycle is initiated (often requires ignition off and on again) in this position and the counter's value still is 0, then you probably have a permanent malfunction.

Values near zero indicate that the malfunction has been detected recently. It may also be that the malfunction exists but the diagnostic trouble code test has not started in these driving cycles, which means that the counter has not been reset. A high counter value indicates that the malfunction was last detected a number of driving cycles ago.

Counter 3 (C#3) (see graph in (Scheme 686) ). Counts the number of driving cycles performed since the malfunction was confirmed the first time. When a malfunction is confirmed the first time, the counter will count up by 1 for every subsequent driving cycle, regardless of if the malfunction is detected or not. Thus, the counter tracks the number of driving cycles since the malfunction was detected the first time. See graph where the counter increases by 1 for every subsequent driving cycle and the value of the counter is finally 6.

A low value indicates that the malfunction was detected for the first time relatively recently. However, a high value indicates that a first detection was performed some time ago.

Counter 4 (C#4) (see graph in (Scheme 686) ). Counts the number of driving cycles in which the malfunction has been confirmed since it was confirmed the first time. The graph shows that after the malfunction was detected the first time, the malfunction has been detected in 3 driving cycles. Thus, after the malfunction was detected the first time, another 6 driving cycles (counter 3), have passed and in these the malfunction has been detected 3 times (counter 3). Simplified, one can say that in this example, the malfunction has occurred/been detected in every other driving cycle, and the malfunction can be assessed as relatively frequent.

A certain indication of a malfunction's intensity can be obtained if you compare the value for counter 4 with counter 3. The closer the value for counter 4 the value is to the value of counter 3, the more frequent the malfunction.

If counters 3 and 4 have the same value, the malfunction has been detected in every driving cycle, which means that the malfunction is frequent.

Counter 5 (C#5). The counter sums up the time in seconds that the control module has been operating since the malfunction first was confirmed and the diagnostic trouble code was stored. The time that the control module has been operating is only counted when it is active, not in "sleep mode". The counter is not shown in the illustration.

Counter 6 (C#6). The counter sums up the time in seconds that the diagnostic trouble code test has been in progress since the malfunction first was confirmed and the diagnostic trouble code was stored. The counter is not shown in the illustration.

Counter 7 (C#7). The counter sums up the time in seconds that malfunction has been confirmed since it first was confirmed and the diagnostic trouble code was stored. The counter is not shown in the illustration.

Scheme 687

Graph A in the illustration. Diagnostic trouble code test active

Shows if the control module's diagnostic trouble code test is active or not. The blue surface indicates when the test is active. Not included as a status identifier.

Graph B in the illustration. Malfunction active

Shows if the malfunction in the vehicle is active or not. The red surface indicates when the malfunction is present (active). Not included as a status identifier.

In the illustration, the control module has detected a malfunction in the second driving cycle, and this malfunction occurs a total of 4 times. Counters can be read out for every diagnostic trouble code in the control module which has this implemented. Driving cycles are indicated with vertical lines. A driving cycle often begins with ignition on and ends with ignition off.

Counter 1 (C#1). Counts number of driving cycles performed since the malfunction was confirmed last . As soon as a malfunction is detected and confirmed, the value is reset. When the malfunction is both detected and disappears in the second driving cycle (graph A in the illustration), counter 1 will count up to 1 first in the following driving cycle (driving cycle 3), that is, a driving cycle has been run through since the last time the malfunction was confirmed.

In driving cycle 4, the counter is updated again, now to value 2. Just after that, the malfunction is detected (graph A in the illustration), the malfunction is confirmed and the counter's value is reset. This sequence is repeated once again in driving cycle 5.

With other words, one can say that if the value is zero, the malfunction exists now or has existed earlier in the current driving cycle. If the vehicle is restarted (often requires ignition off and on again) in this position and the counter's value still is 0, then you probably have a permanent malfunction.

Values near zero indicate that the malfunction has been detected recently. It may also be that the malfunction exists but the diagnostic trouble code test has not started in these driving cycles, which means that the counter has not been reset. A high counter value indicates that the malfunction was last detected a number of driving cycles ago.

Counter 2 (C#2). Counts the number of driving cycles since the last confirmation of the malfunction and where the diagnostic trouble code was performed without detecting malfunction and confirmation of malfunction. Thus, when diagnostic trouble code is performed and no malfunction is detected, the counter will count up by 1 for every driving cycle. As soon as a malfunction is detected and confirmed, the value is reset.

When the malfunction is detected and disappears in the second driving cycle (graph A in the illustration), counter 2 will count up to 1 first in the following driving cycle (run cycle 3). In driving cycle 4 the counter is updated again (diagnostic trouble code test has been run without detecting malfunction), now to value 2. Immediately after that the malfunction is detected (graph A in the illustration), the malfunction is confirmed and the counter's value is reset. This sequence is repeated once again in driving cycle 5.

During driving cycle 6 and 7, the diagnostic trouble code test was run without detecting malfunction and the counter receives the value 2. In driving cycle 8, the diagnostic trouble code test is not run and thus the counter is not updated.

Counter 3 (C#3) . Counts the number of driving cycles performed since the malfunction was confirmed the first time. When a malfunction is confirmed the first time, the counter will count up by 1 for every subsequent driving cycle, regardless of if the malfunction is detected or not. Thus, the counter tracks the number of driving cycles since the malfunction was detected the first time. See graph where the counter increases by 1 for every subsequent driving cycle and the value of the counter is finally 6.

A low value indicates that the malfunction was detected for the first time relatively recently. However, a high value indicates that a first detection was performed some time ago.

Counter 4 (C#4). Counts the number of driving cycles in which the counter's value has been updated first when the malfunction was detected in the driving cycle. The counter has a final value of 3.

A certain indication of a malfunction's intensity can be obtained if you compare the value for counter 4 with counter 3. The closer the value for counter 4 the value is to the value of counter 3, the more frequent the malfunction.

Counter 5 warm-up (C#5). Counts the number of warm-up cycles that have been run since the malfunction light (MIL) has gone off. The counter is not shown in the illustration. Note. Only applies to emission-related systems.

Counter 6 malfunction detection (C#6). The counter counts the number of internal detections of the malfunction that have been run for the diagnostic trouble code. When this counter reaches value +127, the control modules decides that the malfunction is active right now.

When the counter is at value -128, the malfunction is not active. The value is reset for every new driving cycle.

If the value increases towards +127, the control module has detected a malfunction, and for every internal test the value is counted up. When the malfunction no longer exists, the control module counts down to minimum -128.

The value on the control module can only be changed when it has started the test for the diagnostic trouble code. How big each step is that the control module counts up or down the value by to reach the limits +127 or -128 may vary between control modules. Limits +127 and -128 are pre-defined limits in the control module.

In the graph, the counter first counts down to -128 when the diagnostic trouble code test starts. When a malfunction occurs (graph B in the illustration) and the diagnostic trouble code test detects the malfunction, first the counter's value is reset to 0, then it scrolls up to +127. Only then the malfunction is considered to exist. If the malfunction disappears and the diagnostic trouble code test is active, the counter counts down to -128.

Counter 7 malfunction detection - max. current (C#7). Shows maximal value that counter 6 has in the present driving cycle.

The counter is not shown in the illustration.

Counter 8 malfunction detection - max. earlier (C#8). Shows maximal value that counter 6 has in the present and/or has had in earlier driving cycle.

The counter is not shown in the illustration.

STATUS IDENTIFIER

There are status indicator (status identifiers) that can be read out for every diagnostic trouble code. The control module tests every connection (signal) or function more or less periodically, depending on the self-diagnosis' conditions for start.

By reading out the diagnostic trouble code with associated status identifier, then you obtain status for the diagnostic trouble code test that detects the malfunction, as well as if the malfunction exists now or not.

Note. Status identifier, Counter and Frozen values are the most important factors to deciding the malfunction's nature, that is, to decide

1. when the malfunction was detected (frozen values, counters)
2. what the driving conditions were at the time (frozen values)
3. status for the test (self-diagnosis) (status identifier)
4. how frequent the malfunction is (counter).

All status identifiers (or malfunction detection counters) do not have to be introduced in one control module, this varies from system too system. All status identifiers restarts the count every time a new driving cycle/operation cycle starts or when erasing diagnostic trouble codes. Status identifiers should be read off continuously as the different identifiers can be updated later on.

The following describes possible status identifiers.

Note. Status identifiers for systems with diagnostics Volvo Diagnos II is slightly different from status identifiers for diagnostic version Generic Global Diagnostics (GGD). See below.

When erasing diagnostic trouble codes, the diagnostic trouble code's status identifier is erased.

MALFUNCTION DETECTING

A malfunction that is detected is assessed by the control module's self-diagnosis. First after, e. g., a certain time, a certain number of driving cycles, certain driving/operation or other conditions, the control module decides if it is a real malfunction or not.

When self-diagnosis has determined that a real malfunction exists, you can say that the malfunction is confirmed and the malfunction is stored in the control module's trouble code memory in the form of diagnostic trouble codes.

If a malfunction disappears, the diagnostic trouble code will remain for a tome in the diagnostic trouble code memory, but the status of the diagnostic trouble code changes. How long the diagnostic trouble code is stored in the diagnostic trouble code memory is different from control module to control module, as well as between different vehicle models (generation of vehicle model).

In some systems the diagnostic trouble code will be stored until it is erased with the diagnostics tool. In other systems the diagnostic trouble code is erased automatically by the control module after, e. g., a certain number of malfunction-free driving cycles. A new driving cycle (operation cycle) is usually started every time the ignition is turned on.

Information about the nature of the malfunction is stored for every diagnostic trouble code

1. when the malfunction was detected (frozen values, counters)
2. what the driving conditions were at the time (frozen values)
3. status for the test (diagnosis) (status identifier)
4. how frequent the malfunction is (counter).

Exactly what is stored is different from control module to control module,, as well as between different vehicle models (generation of vehicle model).

If the system is provided with warning light, it is lit when the ignition key is turned to position II. The warning light will go off after a certain number of seconds when no malfunction is detected on the control system.

The warning light will be on in case of a malfunction of the control system. The warning light will be lit first after the malfunction is confirmed as a real malfunction.

Scheme 688

Volvo has developed a wide range of tools and information for easier and faster troubleshooting of the vehicle and its different systems. The range includes service and troubleshooting information, integrated self-diagnostics in control modules, measuring instrument for exhaust analysis, diagnostic tools, etc.

Troubleshooting or diagnostics are performed by the mechanic using two different concepts; Off Board Diagnostics (diagnostics outside the vehicle) or On Board Diagnostics (diagnostics system in the vehicle).

Off Board Diagnostics (diagnostics outside the vehicle) is done without help from the control module's self-diagnosis. Examples of these are

1. Breakout box and multimeter to measure signals.
2. Mechanic's troubleshooting using hearing, touch, and vision as well as experience.
3. Diagnostic tools that are connected in parallel between control module and connector.
4. Cylinder leak tester.

On Board Diagnostics (diagnostic systems in the vehicle) is done using the control module's self-diagnosis and is read out and presented using a diagnostics tool.

Scheme 689

The term Diagnostics refers to true recognition and designation of an illness. The term comes from the Greek dia = through, and gnosis = knowledge. The purpose of a diagnosis is to give a summarized term for the different symptoms that the "sick" describes, and thus be able to give a specific treatment.

The control module in the vehicle includes software to manage intended function (e. g., control all functions of an engine), to monitor the system's components and functions. Monitoring (self-diagnosis) detects any malfunctions, stores these, activates protective actions (back-up modes) and, in some cases, warns the driver.

Monitoring (diagnosis) is always activated when the system is on but tests are started and run according to different pre-defined conditions. A malfunction that is detected is first assessed by monitoring, after, e. g., a certain time, a certain number of driving cycles, certain driving/operation cases or other conditions, the control module decides if it is a real malfunction or not. When monitoring determines that a real malfunction exists, it can be said that the malfunction is confirmed and the malfunction is stored.

The basic goal of self-diagnosis in control modules is to detect and report malfunctions in a control module or its connected components and cables. Part of the goal (found in legal requirements) is also to detect malfunctions that affect emissions as well as malfunctions that may cause subsequent damage to emission-related components.

Self-diagnosis shall also warn for malfunctions that mean a safety risk for drivers, passengers, and vehicles that otherwise would not cause a symptom and thus not be detected. This applies to, e. g., brake system and SRS-system.

Self-diagnosis shall be used by workshops as one of the tools for taking care of the symptom (property/malfunction) that the customer experiences. After the malfunction cause is found (via troubleshooting) and taken care of (via repair), self-diagnosis can also be used to verify that the malfunction cause has been fixed and that the customer's symptom does not exist any longer.

Note. The control module's self-diagnosis (diagnostic trouble code tests) cannot detect all malfunctions that may occur in a vehicle. This primarily applies to mechanical malfunctions but also some electrical malfunctions, e. g., poor connection to battery, or relay spools for a relay are monitored but the function/circuit that the relay controls is not monitored. Unfortunately, sometimes the control module's self-diagnosis can miss to generate a diagnostic trouble code for a malfunction where the customer experiences a symptom (malfunction), and sometimes it may generate a diagnostic trouble code despite the customer not experiencing any symptom (malfunction). This is because customers have different sensitivity to malfunctions (how easily the symptom is detected) and because it is not always to optimize self-diagnosis for all conditions that may occur during the vehicle's life. That is why you should not entirely rely on the vehicle's diagnostic trouble codes. Diagnostic trouble codes should only be regarded as indicators of probably malfunction sources. If the customer experiences a symptom (malfunction) but diagnostic trouble codes are not stored, this does not mean that the vehicle is trouble-free.

Worth keeping in mind when troubleshooting

1. When there is so much electronic equipment in the vehicles, it is easy to blame the "complex" electronics and forget the normal basics for, e. g., an engine's function. But the basics are the same today as when we had carburetor engines.
2. A common mistake in troubleshooting is to quickly restricting yourself to a certain area without having checked basic functions, e. g., that the ignition system and engine are in good mechanical condition, the battery is fully charged, fuses are intact.
3. Troubleshooting information gives very good guidance when troubleshooting and is almost impossible to do without. By using the customer's symptom, developed troubleshooting methods with, e. g., diagnostic trouble code information, you are quickly guided to being able to pin-point the malfunction.

Note. The electronic components in the control systems are very reliable and seldom cause any malfunctions.

This document describes the following

1. Background to why self-diagnosis is found in the vehicle.
2. Diagnostic services, what they do.
3. Using the self-diagnosis.
4. Diagnostic versions and its communication method.
5. Tools for reading out diagnosis.
6. Where I find the information.

TO DECIDE THE INTENSITY OF A MALFUNCTION

Note. Examples 1-5 (below) are based on counters for diagnostic concept Generic Global Diagnostic (GGD).

When a malfunction is intermittent or has unknown status, the diagnostic trouble code's counter is very useful to decide

1. How many driving cycles that have passed since the malfunction was detected the first time as well as since the malfunction was detected.
2. During how many driving cycles that the control module has detected the malfunction during a certain period, as well as how many driving cycles that the control module has not detected the malfunction. That the control module has not detected the malfunction may be due to the control module not having started the test for the malfunction, conditions to detect the malfunction are not fulfilled, or that the malfunction no longer exists.

The purpose of interpreting the counters is that it is possible to understand the malfunction's intensity, that is, show "how much" intermittent the malfunction is, as well as help in assessing if the chances to repeat the malfunction and customer symptom, and then succeed with troubleshooting.

If you read out the diagnostic trouble code information and it shows that the diagnostic trouble code test runs at least once every driving cycle (e. g., when driving), the counters' value may be very important when assessing the diagnostic trouble code's status and actions. However, if start of diagnostic trouble code test and its conditions are difficult to achieve, the counters' values should be considered to be of less importance.

Counters 1 and 3 show driving cycles. Counters 2 and 4 also show driving cycles, but then really a "share" of counters 1 and 3, respectively. In principle, counter 4 shows how many times that the customer should have detected symptoms.

Note. For systems with diagnostic concept Generic Global Diagnostics (GGD). If many diagnostic trouble codes are stored at the same time, then certain diagnostic trouble codes (the oldest) will have these frozen values/counters erased, this to save memory in the control module. These diagnostic trouble codes will then only have counter 2 left. Note also that counter 2 will also be erased when the memory is full, but often later than when other counters are erased.

Note. For system with diagnostic concept Volvo Diagnostics II. If many diagnostic trouble codes are stored at the same time, the control module keeps at least half of the oldest and half of the newest diagnostic trouble codes in the trouble code memory.

Note. For diagnostic trouble codes where the malfunction is not detected for many driving cycles and where the malfunction is detected again, then frozen values and counter values are written over with new values, that is, the diagnostic trouble code is considered "new".

Example 1, Intermittent malfunction

Scheme 690

1. Counter 1 = 5
2. Counter 2 = 2
3. Counter 3 = 25
4. Counter 4 = 10
5. Driving cycles

After the malfunction has been detected for the first time (driving cycle 0) the malfunction has been detected again in 9 of the first 20 driving cycles. Using this, the conclusion can be drawn that in 11 driving cycles the test has not been run or the malfunction has not been found, or a combination of these. After the last time that the malfunction was detected, 5 driving cycles have passed, where the test was run in 2 driving cycles without detecting a malfunction.

Conclusion: Intermittent malfunction

Assessment: Good possibility to repeat the malfunction and customer symptom, and thus succeed with troubleshooting, as the malfunction has been found quite recently in several driving cycles.

Example 2, Permanent malfunction

Scheme 691

1. Counter 1 = 0
2. Counter 2 = 0
3. Counter 3 = 25
4. Counter 4 = 26
5. Driving cycles

After the malfunction has been detected for the first time the malfunction has been detected again in all following driving cycles.

Conclusion: Permanent malfunction

Assessment: Very good possibility to repeat the customer symptom and thus succeed with troubleshooting, as the malfunction has been found in every driving cycle. Since the malfunction has been detected during the present driving cycle it does not really matter for troubleshooting if the malfunction has been detected in all previous driving cycles or not.

The counter show more how "sure" the malfunction is as well as that it can confirm if the customer experienced the malfunction as the counter indicates.

Example 3, Intermittent malfunction

Scheme 692

1. Counter 1 = 122
2. Counter 2 = 122
3. Counter 3 = 125
4. Counter 4 = 4
5. Driving cycles

After the malfunction has been detected for the first time the malfunction has been detected again in the 3 following driving cycles. After the last time that the malfunction was detected, 122 driving cycles have passed, where the test has been run in 122 driving cycles without detecting a malfunction.

Conclusion: Intermittent malfunction

Assessment: Not very good chance to repeat the malfunction and the customer symptom and thus succeed with troubleshooting, as the malfunction has only been detected in a few driving cycles a very long time ago.

The less driving cycles a malfunction has been detected in and the greater the number of driving cycles since the malfunction was detected the last time, the more difficult it is expected to be to repeat the malfunction and the customer symptom and thus succeed with troubleshooting.

This can be read off by the lower value is on counter 4 and the higher the value is on counter 1 and 2, as well as the lower the difference is between the value on counter 3 and counter 2, the more difficult it is expected to be to repeat the malfunction and the customer symptom and thus succeed with troubleshooting.

Example 4, Intermittent malfunction

Scheme 693

1. Counter 1 = 25
2. Counter 2 = 25
3. Counter 3 = 25
4. Counter 4 = 1
5. Driving cycles

After the malfunction has been detected for the first time, the malfunction has never been detected again. After the last time that the malfunction was detected, 25 driving cycles have passed, where the test has run in 25 driving cycles without detecting a malfunction.

Conclusion: Intermittent malfunction

Assessment: Not very good chance to repeat the malfunction and the customer symptom and thus succeed with troubleshooting, as the malfunction has only been detected in one driving cycle quite a long time ago.

Example 5 Unknown status

Scheme 694

1. Counter 1 = 25
2. Counter 2 = 0
3. Counter 3 = 25
4. Counter 4 = 1
5. Driving cycles

After the malfunction has been detected for the first time, the malfunction has never been tested and/or detected. After the last time that the malfunction was detected, 25 driving cycles have passed where the test has not been started. Since the diagnostic trouble code test has not started anymore, it cannot be decided if the malfunction exists or not.

Conclusion: Unknown status

Assessment: Read diagnostic trouble code information and try to achieve condition so that the diagnostic trouble code test is started and run, which makes it possible to detect the malfunction. If the malfunction is detected, chances are very good to repeat the customer symptom, and thus succeed with troubleshooting when the malfunction has been found in the current driving cycle.

If the malfunction was not detected even though conditions are fulfilled, then chances are less good to repeat the customer symptom, and thus succeed with troubleshooting as the malfunction has not been found in the current driving cycle.

INFORMATION

Information is found in VIDA (Volvo scan tool).

Note. Information for older cars (model year -1998) is read out using Volvo System Tester, Diagnostic socket with light-emitting diode or Volvo Diagnostic Key.

Scheme 695

The control panels in the driver's door are directly connected to the driver door module (DDM). Driver door module (DDM) receives the input signals from the control panels. The control module then carries out the function or transmits the signal on using CAN and LIN communication to the control module which is carrying out the function.

The following functions can be controlled via the control panels

1. all power windows
2. child-proof lock (only applies to S40/V50)
3. all windows up/down (instead of child-proof lock) (only applies to C70)
4. operating the door mirrors
5. central locking.

Scheme 696

The control panels in the passenger door are directly connected to the passenger door module (PDM).

Passenger door module (PDM) receives the input signals from the control panels. The control module then carries out the function or transmits the signal on using CAN communication to the control module which is carrying out the function.

The following functions can be controlled via the control panels

1. power window mechanism in the passenger door
2. central locking.

The passenger door module (PDM) and driver door module (DDM) have diagnostics for the front door locks.

Scheme 697

The window lift mechanism on the driver's side is operated via the control panel in the driver's door. The window lift mechanism on the passenger side is operated either via the control panel in the passenger door or via the control panel in the driver's door.

The rear power windows can be operated via the control panel in the driver's door or via the Left rear door module (LDM) or Right rear door module (RDM) (only the driver's door for the C70). The power windows can be operated when the ignition key is in position I or II. The power windows can also be operated from when the ignition is switched off until one of the front doors is opened.

The control panel in the driver's door has four spring loaded switches which operate the individual windows

The control panels in the passenger door, left rear door and right rear door each have a spring loaded switch to operate the relevant power window.

The switches for the window lift mechanisms in all doors have five positions which control the position of the window (only applies to the front windows in the C70)

0) Normal position where the function is passive.

1) step 1 upwards, raises the window for as long as the button is activated.

2) step 2 upwards, automatically fully closes the window (AUTO-UP).

1) step 1 downwards, lowers the window for as long as the button is activated.

2) step 2 downwards, fully opens the window automatically (AUTO-DOWN).

Instead of child lock switch

In the C70 the control panel in the driver's door is equipped with a button, which operates all windows up or down.

This switch has three positions that control

1. Normal position where the function is passive.
2. Down, automatically operates all windows down (AUTO-DOWN).
3. UP, operates all windows up as long as the button is held in.

All power window lift mechanisms in the front doors have an integrated function to prevent trapping.

Only the front power windows in the C70 have the integrated function to prevent trapping. When AUTO-UP is activated, the window lift mechanism detects whether there is any resistance, i. e. whether too much force is required to close the window. If so, the window stops and then lowers slightly. The anti-trapping system is active during AUTO-UP if the window is open more than 3 mm.

A diagnostic trouble code (DTC) is stored if for any reason the power window mechanism is unable to determine the window position. If this should happen, the power window mechanism must be re-initialized. This is carried out via a diagnostic function in VIDA (Volvo scan tool).

The passenger door module (PDM) and driver door module (DDM) have diagnostics for the window lift mechanisms and Hall sensors in the front doors.

The window lift mechanisms and Hall sensors in the rear doors can be diagnosed via the control modules in the front doors on the relevant side of the vehicle.

Scheme 698

Motors

The door mirror motors are operated via the control panel in the driver's door.

The mirrors can be adjusted in the X and Y axes via the two motors for each mirror. Two buttons on the control panel, marked L and R, are used to select either the right or left-hand mirror for adjustment. An LED lights in the button that is activated. Only one button can be activated at any one time (left or right). X and Y axis adjustment is made using a control which maneuvers the mirror in the selected direction for as long as the button is pressed (or until the mirror reaches a limit position). To deactivate the adjustment control, press the left or right button again so that the LEDs are off. The mirrors can be adjusted when the ignition key is in position I or II.

Power seats with memories for the door mirrors are optional equipment. (only S40/V50 2004 and C70). This function requires that the position of the mirrors is saved when the car is locked. Two sensors in each mirror register the mirror position in the X and Y axes.

The door windows can be equipped as an option with a motor that allows the mirror housing to be folded in. The motor for folding in the door mirrors is diagnosed and powered by the driver door module (DDM) and passenger door module (PDM) respectively.

The motors and sensors used to set the position of the door mirrors form one unit and cannot be replaced separately.

Heating

The door mirrors contain a heating loop to defrost the glass. The heating loop is on the reverse of the mirror glass. In the event of a fault, the entire mirror glass must be replaced. The heating loops are supplied with power and ground by the driver door module (DDM) and passenger door module (PDM), which also have diagnostics for the loops. However the function is activated by the climate control module (CCM).

Lights in the door mirrors

The door mirrors can be equipped with lamps. The lamps are mounted on the underneath of the mirror housing. The driver door module (DDM) and passenger door module (PDM) have diagnostics for the outputs for the lamps. However the function is activated by the central electronic module (CEM) and the remote control.

Outside temperature

In the left mirror there is a temperature sensor which measures the outside temperature. The temperature information is used by the driver information module (DIM). The temperature sensor is directly connected to the central electronic module (CEM).

The temperature sensor in the left mirror housing can be replaced separately. The temperature sensor is diagnosed via the central electronic module (CEM).

Turn signal lamps

There are turn signal lamps in both door mirror housings. These are mounted at the ends of the mirror housings. The driver door module (DDM) and passenger door module (PDM) have diagnostics for the outputs for the lights in the turn signal lamps.

However, the function is activated via the left control stalk. A signal is transmitted by the steering wheel module (SWM) to the driver door module (DDM) respectively passenger door module (PDM), via the central electronic module (CEM).

DRIVER DOOR MODULE (DDM)

See DIAGNOSTIC FUNCTIONS, DRIVER DOOR MODULE (DDM) .

PASSENGER DOOR MODULE (PDM)

See DIAGNOSTIC FUNCTIONS, PASSENGER DOOR MODULE (PDM) .

This function can be used to continuously read off the values and status of parameters from the passenger door module (PDM).

Use this option to activate components / functions in the passenger door module (PDM).

With this option it is possible to read programmed data and to program in data.

Note. If the control module has been replaced, the position of the windows must be initiated using a diagnostic function. A window must be in its uppermost position before it can be initiated.

No customer related programming is available in the control module.

This function can be used to continuously read off the values and status of parameters from the driver door module (DDM).

Use this option to activate components / functions in the driver door module (DDM).

With this option it is possible to read programmed data and to program in data.

Note. If the control module has been replaced, the position of the windows must be initiated using a diagnostic function. A window must be in its uppermost position before it can be initiated.

No customer related programming is available in the control module.

New software can be downloaded into the passenger door module (PDM) and the driver door module (DDM). When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK the software is downloaded to the control module.

If the comparison between the car and Volvo central database is not OK, the database is updated with the car configuration. When this is complete the software is downloaded.

The window positions must be initialized again after replacing the control module. This is so that the new control module stores the closed position of the window. Initialization is carried out using the diagnostic tool.

If the car has power seats with memory for the door mirrors (only S40/V50 2004 and C70), this function can be switched off. This means that the personal settings for the door mirrors, based on the remote control used to unlock the door, can be deactivated. Deactivation is carried out using the diagnostic tool. These customer parameters are stored in the control module but not in the Volvo central database. This means that the deactivation must be repeated when hardware is replaced.

CENTRAL LOCKING

See central locking.

Scheme 699

Operating the window from the driver's seat

The window is operated by the switch in the control panel (3/81). The motor for the power window on the driver's side is controlled directly from the driver door module (DDM) (3/126). The motor for the power window on the passenger side is controlled via controller area network (CAN) communication from the driver door module (DDM) to the passenger door module (PDM) (3/127). The signals for operating the rear window on the driver's side are transmitted from the driver door module (DDM) to the rear window using LIN-communication. The signals for operating the rear window on the passenger side are transmitted from the driver door module (DDM) via the controller area network (CAN) to the passenger door module (PDM) and then to the rear window using LIN-communication.

Operating the front window on the passenger side

The passenger door module (PDM) (3/127) only operates the front window on the passenger side. The window is operated by the switch in the control panel (3/82). The signal is sent via the passenger door module (PDM) to the power window motor on the passenger side.

Operating the window in the left-hand rear door (does not apply to the C70)

Left rear door module (LDM) (3/128) can only operate the window in the left rear door. The window is operated by the switch in the control panel (3/85). The signal is sent via the left rear door module (LDM) to the power window motor in the left rear door.

Operating the window in the right-hand rear door (does not apply to the C70)

Right rear door module (RDM) (3/129) can only operate the window in the right rear door. The window is operated by the switch in the control panel (3/86). The signal is sent via the right rear door module (RDM) to the power window motor in the right rear door.

Activating the child lock (does not apply to the C70)

If the child lock is activated from the driver door module (DDM), the rear windows cannot be operated from the rear doors. The child lock is operated via the switch in the control panel on the driver's side. A signal is transmitted to the driver door module (DDM) and on via LIN-communication to the left rear door module (LDM) and right rear door module (RDM) which shut off window operation in the respective doors.

Operating all windows at the same time (only applies to C70)

On the control panel for the C70 there is a button for operating all windows up or down.

This switch has three positions that control

1. Normal position where the function is passive.
2. Down, automatically operates all windows down (AUTO-DOWN).
3. UP, operates all windows up as long as the button is held in.

The functions in the door mirrors (6/62 left) (6/63 right) are controlled from the control panels for the driver door module (DDM) (3/126) or passenger door module (PDM) (3/127) are

1. setting the mirror position
2. folding in the door mirrors
3. heating the mirrors
4. approach lighting/guide lighting
5. turn signal lamps.

The left door mirror has a temperature sensor for the outside temperature. The signal from the temperature sensor is directly connected to the central electronic module (CEM). The signal is not controlled by the driver door module (DDM) or the passenger door module (PDM).

Adjusting the mirror position

Scheme 700

The position of the mirror is controlled using buttons on the control panel on the driver's side (3/81). The driver door module (DDM) (3/126) transmits a signal directly to the mirror on the driver's side (6/62). When adjusting the mirror on the passenger side (6/63), a signal is transmitted via the driver door module (DDM) to the passenger door module (PDM) (3/127) on the controller area network (CAN). The passenger door module (PDM) transmits the signal to the door mirror.

If the vehicle has power seats with memory for the door mirrors (only S40/V50 2004 and C70), the position of the mirrors is stored by two potentiometers. The signal indicating the position in the X and Y axes is received by the driver door module (DDM) and passenger door module (PDM). When one of the buttons on the control unit for the power seat is activated, a signal is transmitted from the power seat module (PSM) (3/26) (for C70; power seat module, left (PSL)) to the driver door module (DDM) and passenger door module (PDM). This adjusts the door mirrors to the stored position. The stored position can also be set according to which remote control is used to unlock the vehicle.

Folding in the door mirrors

Scheme 701

The mirror is folded by holding the L and R buttons on the control panel (3/81) on the driver's side. A signal is transmitted via the driver door module (DDM) (3/126) to the passenger door module (PDM) (3/127) via the controller area network (CAN). The control modules send the signal on to each door mirror (6/62 and 6/63), which fold each mirror in or out.

Heating the mirrors

Scheme 702

Mirror heating is activated at the same time as rear windshield heating (there is no rear windshield heating on the C70). When the switch for heated rear windshield / door mirrors is pressed the climate control module (CCM)) (3/112) activates rear windshield heating. At the same time the signal is sent via the controller area network (CAN) to the driver door module (DDM) (3/126) and the passenger door module (PDM) (3/127) to activate the door mirror heating. When the Driver door module (DDM) respectively, Passenger door module (PDM) receive the signal, the outputs for each door mirror are powered (6/62 and 6/63). The function is switched off at the same time as the rear window defrosting. This can happen in three different ways

1. If the switch for heated rear windshield/door mirrors is pressed again after activation, the function is switched off, using a signal from the climate control module (CCM)
2. The heating switches off automatically 12 minutes after activation. The driver door module (DDM) and the passenger door module (PDM) receive a signal from the climate control module (CCM) which requests that the function is activated
3. The heating is also switched off if the ignition is switched off.

Approach lighting/Guide lighting

Scheme 703

The approach lighting is activated using the remote control for the vehicle. The function can only be activated when the ignition is off. When the yellow button on the remote control is pressed, the central electronic module (CEM) (4/56) receives an activation signal which is sent onwards on the controller area network (CAN). The driver door module (DDM) (3/126) and passenger door module (PDM) (3/127) receive the signal and switch on the lighting for the left door mirror (6/62) and the lighting for the right door mirror (6/63). The function is deactivated by pressing the button on the remote control again. A signal is then sent from the central electronic module (CEM) to the driver door module (DDM) and passenger door module (PDM) requesting that the function is switched off. The function is also switched off when the ignition is switched on.

The guide lighting is activated using the left control stalk (the key must be removed from the ignition switch). Steering wheel module (SWM) (3/254) transmits a signal via the controller area network (CAN) to the central electronic module (CEM). When the car is then locked, the central electronic module (CEM) sends a signal onwards via the controller area network (CAN) to the driver door module (DDM) and passenger door module (PDM), which turn on the lights in the door mirrors. The lights are part of the guide lighting function and remain on for a set time (30, 60 or 90 seconds).

Measuring the outside temperature

Scheme 704

The left door mirror has a temperature sensor for the outside temperature. The signal from the temperature sensor is directly connected to the central electronic module (CEM). The signal is not controlled by the driver door module (DDM) or the passenger door module (PDM).

During operation of the roof, all side windows lower at least 80 mm to prevent friction between the roof unit and the windows. A signal is transmitted from the Convertible Roof Module (CRM) via the CAN network to the Driver door module (DDM) and the Passenger door module (PDM). These send a signal on via LIN to the Left rear door module (LDM) and Right rear door module (RDM). When the door are opened the window lowers 4 mm to prevent wearing the roof's rubber weatherstrip. After the door has been closed the window goes up behind the rubber weatherstrip to prevent leakage.

The driver door module (DDM) and the passenger door module (PDM) are broadly similar in terms of functionality. Both these control modules are described in common in this document. In those cases the differences between the driver door module (DDM) and the passenger door module (PDM) are given. The main task of both control modules is to manage

1. the power window mechanism
2. the door lock
3. door mirror adjustment
4. door mirror folding
5. door mirror heating
6. approach lighting
7. turn signal lamps in the door mirrors.

The control modules are in their respective doors. The driver door module (DDM) is on the driver's side. The passenger door module (PDM) is on the passenger side. The control modules are integrated with the power window lift motors. The control modules must also be replaced when replacing the power window lift motors.

There are two types of control module, Standard and High. The difference between the variants is that Standard does not have deadlocks, memory function for the mirrors (only S40/V50 2004 and C70) or approach lighting.

The driver door module (DDM) and passenger door module (PDM) communicate with directly connected components and with other control modules and components connected via controller area network (CAN).

The driver door module (DDM) and passenger door module (PDM) communicate with the control module for the rear doors for their respective sides of the vehicle via LIN communication.

Both control modules check activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if either of the control module detects a fault. The diagnostic trouble codes (DTCs) for the control modules in the rear doors are stored in the respective control module in the front doors.

Any diagnostic trouble codes (DTCs) are stored in the relevant control module memory. The data can be read off.

A simple way to ensure that the control modules are powered and grounded is to activate one of the functions that are operated via the switches on the control panels in the respective doors. The control module is powered and grounded if any of the functions are working.

Scheme 705

Left rear door module (LDM) and Right rear door module (RDM) are completely the same and only manage the functions for power windows and door locks in their respective door.

The control modules are positioned in their respective doors (in the C70 they are located under the respective rear side window). The control modules are integrated with the power window lift motors. The control modules must also be replaced when replacing the power window lift motors.

There are two types of control module, Standard and High. The difference between the variants is that Standard does not have deadlocks or child-proof locks. (child-proof locks does not apply to the C70).

The left rear door module (LDM) and right rear door module (RDM) communicate with directly connected components and with the control module for the front door on the relevant side of the vehicle via LIN-communication.

Both control modules check activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if either of the control module detects a fault. The diagnostic trouble codes (DTCs) for the control modules in the rear doors are stored in the respective control module in the front doors.

Any diagnostic trouble codes (DTCs) are stored in the relevant control module in the front doors. The data can be read off.

A simple way to ensure that the control modules are powered and grounded is to activate one of the functions that are operated via the switches on the control panels in the respective doors. The control module is powered and grounded if any of the functions are working.

The table below summarizes the input signals to and output signals from the driver door module (DDM) and passenger door module (PDM). The signal types are divided into directly connected signals, LIN and CAN communication. The illustration below (Scheme 706) displays the same information with the Volvo component designations.

Scheme 706

This function can be used to read off the values and status of parameters from the driver information module (DIM).

For further information about the different parameters, see: DESCRIPTION OF PARAMETERS

Use this option to activate components / functions in the driver information module (DIM).

For further information about activations, see: DESCRIPTION OF COMPONENT / FUNCTIONS ACTIVATION

PROGRAMMING CUSTOMER PARAMETERS

Use this function to program customer parameters in the driver information module (DIM).

For further information, see: DESCRIPTION OF THE PROGRAMMED VALUES

New software can be downloaded into the driver information module (DIM). When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK the software is downloaded to the control module.

If the comparison between the car and the Volvo central database does not correspond, the database is updated with the configuration of the car. The software download then begins.

The control module is integrated in the driver information module (DIM). When replacing the control module the entire combined instrument panel must also be replaced.

The language in the combined instrument panel can be changed. This is done by ordering new software for the driver information module (DIM) from the replacement parts catalogue. In the replacement parts catalogue there is software for reloading the driver information module (DIM) (Reloading DIM) and software for changing to a number of different languages. Reloading reloads the same software that was installed before the control module was replaced.

There are other functions in the combined control module which can be ordered. However, these are not downloaded into the driver information module (DIM) but into the central electronic module (CEM). These are functions such as the trip computer.

A number of customer parameters can be programmed into the driver information module (DIM). This is not done using software downloads but using VIDA (Volvo scan tool).

To change these customer parameters, the car configuration file must be updated so that the market code for the driver information module (DIM) is reset to "User Defined". This update is made through a software download. This only needs to be done once.

The following customer parameters can be programmed into the driver information module (DIM)

1. Conditions for the service message to be displayed, mileage, time and engine hours
2. Unit of temperature. The options are Fahrenheit and Celsius
3. Units in the trip computer (only applies to vehicles with trip computers). Fuel consumption can be displayed in liters per 100 km, miles per GB Gallon, miles per US Gallon and kilometers per liter
4. 12 or 24 hour clock display.

These customer parameters are stored in the driver information module (DIM) but not in the Volvo central database. This means that the customer parameters must be reprogrammed when hardware is replaced.

Scheme 707

There is a display for text messages etc in the center of the upper section of the driver information module (DIM) (5/1). This provides the driver with supplementary information about the various warning symbols. This is to reduces the number of different symbols in the combined instrument panel. Other types of messages, such as the functions of the trip computer, are also displayed.

If the vehicle is equipped with the function automatic start/stop of engine guiding information is shown about the function.

Depending on the situation, request for these messages may come from Central electronic module (CEM) (4/56) or Steering wheel module (SWM) (3/254).

There is an order of priority where all warning messages have precedence.

Scheme 708

The outside temperature gauge is integrated in the upper display. This function displays the outside temperature. If there is a risk of icy road conditions, a snow flake symbol is displayed to warn the driver. The snowflake is displayed in a range of -5 to +2 °C.

A sensor which detects the outside temperature is mounted in the left-hand door mirror (6/62). The temperature sensor is directly connected to the central electronic module (CEM) (4/56) which then forwards the signal to the driver information module (DIM) (5/1). The temperature is displayed in Celsius or Fahrenheit, depending on the market, in increments of one degree. The unit for temperature display is a programmable customer parameter.

Scheme 709

The only function of the clock is to display the time in hours and minutes. The clock is in the upper display.

Information is transmitted from the central electronic module (CEM) (4/56) to the driver information module (DIM) (5/1) via the controller area network (CAN).

The customer can adjust the time using a knob at the bottom of the driver information module (DIM). During adjustment, the driver information module (DIM) transmits the new time to the central electronic module (CEM). The central electronic module (CEM) registers the change and updates its clock accordingly.

The customer can select the way in which the time is displayed

1. 12 hour clock. The time is automatically displayed with AM or PM
2. 24 hours clock.

SEAT BELT REMINDER

The seat belt reminder reminds the driver to put on the seat belt. There are two versions of the seat belt reminder

1. European and
2. American.

The difference between the two is described below. The signals which indicate the variant (European or American) are transmitted by the central electronic module (CEM) (4/56) via the control area network (CAN). Two small symbols light by the lamp in the roof to indicate that the seat belt is not fastened. The driver information module (DIM) (5/1) emits an audible signal to warn the driver that the seat belt is not fastened.

European version (applies up to and incl. structure week 200650)

All the seats in the vehicle are monitored.

The light symbols will light in the Driver information module (DIM) and in the lamp module in the roof if the belt is not fastened when the ignition is switched on. There is an audible signal from the driver information module (DIM) when the vehicle speed exceeds 10 km/h. This continues for 6 seconds until either the seat belt is fastened or reverse gear is selected or the audible signal is switched off using the Read button on the control stalk. The audible signal's frequency increases at speeds exceeding 25 km/h and at speeds exceeding 40 km/h the volume also increases.

For the backseat there is status monitoring that generates various text messages depending on which belts are used. These messages are turned off 30 seconds after the vehicle has reached speed above 10 km/h.

European version (applies from and incl. structure week 200651)

All the seats in the vehicle are monitored.

Front seats

The light symbols will light in the Driver information module (DIM) and in the lamp module in the roof if the belt is not fastened when the ignition is switched on. There is an audible signal from the driver information module (DIM) when the vehicle speed exceeds 10 km/h. This continues until the belt is fastened or reverse engaged. The audible signal's frequency increases at speeds exceeding 25 km/h and at speeds exceeding 40 km/h the volume also increases. If the loudest volume is activated, above 40 km/h, it will continue for 90 seconds even if the speed drops below 40 km/h.

Backseat

For the rear seat there is a status monitor that generates different text messages depending on which seat belt is used. These messages go out 30 seconds after the vehicle has reached a speed greater than 10 km/h if a belt is fastened. If a belt is unfastened, the driver is alerted via text message as well as light and audible signals. The signals follow the front seat.

All messages can be switched off using the Read button on the control stalk.

American version (-2004)

When the ignition is switched on, the symbols light continuously for 6 seconds, or until the driver's seat belt is fastened. At the same time there will be a ringing sound from the driver information module (DIM) for the same period of time. If the driver then undoes the seat belt, the audible signal will not resume if more than 6 seconds have passed since the ignition was switched on.

American version (2005-2008)

When the ignition is switched on, the symbols light continuously for 6 seconds, or until the driver's seat belt is fastened. At the same time there will be a ringing sound from the driver information module (DIM) for the same period of time. The seat belt reminder for the front passenger will also be activated after 1 minute. There will then be a 6-second signal every 30 seconds should either the driver or the front passenger not have their seat belt fastened. Once 6 seconds have passed since the ignition was switched on, the seat belt reminder is deactivated and there is no audible signal.

American version (2009-)

All the seats in the vehicle are monitored.

Front seats

The light symbols will light in the Driver information module (DIM) and in the lamp module in the roof if the belt is not fastened when the ignition is switched on. There is an audible signal from the driver information module (DIM) when the vehicle speed exceeds 10 km/h. This continues for 6 seconds until either the seat belt is fastened or reverse gear is selected.

Backseat

For the rear seat there is a status monitor that generates different text messages depending on which seat belt is used. These messages go out 6 seconds after the vehicle has reached a speed greater than 10 km/h if a belt is fastened. If a belt is unfastened, the driver is alerted via text message as well as light and audible signals. The signals follow the front seat.

All messages can be switched off using the Read button on the control stalk.

Scheme 710

The function of the trip odometers and the odometer is to display the three available odometer modes. The two settings are the total mileage of the car and the mileage since the two trip odometers were last set to zero. The trip odometers can be reset individually. The odometer and one of the two trip odometers are always displayed. Press the button briefly to switch between the two trip odometers. Hold the button in longer to reset the trip odometer. The driver information module (DIM) must also be powered.

The central electronic module (CEM) (4/56) receives a speed signal from the brake control module (BCM) (4/16) which is transmitted on the high speed section of the control area network (CAN). The central electronic module (CEM) then transmits the signal on to the driver information module (DIM) (5/1) via the low speed section of the control area network (CAN). The distance traveled is saved every fourth kilometer and the value is stored in the central electronic module (CEM).

SERVICE MESSAGE

The following information applies to vehicles of model year 2008 and earlier

The service message appears the first time the ignition is switched on after the condition for servicing has been fulfilled. The service message is shown every 120 seconds (model year 2006- 240 seconds) each time the ignition is switched on until it is reset. The service message also appears 1 minute after the ignition is switched off (applies to model year 2006-). The service message consists of the text "Time for service". The condition for the service message to appear can be programmed based on three different parameters

1. mileage
2. time and
3. engine hours.

The quality of the engine oil also has an impact on when the message is displayed. However this parameter cannot be programmed.

The following information applies to vehicles of model year 2009 and later

In order to give the car owner greater possibility of having maintenance service done at the right time, the driver is informed when it is time to book a time for maintenance service. The service message is shown before the actual conditions for the service interval are fulfilled, to avoid exceeding the service interval.

The service message is shown as a text message in the Driver information module (DIM) in the following steps

1. Book time for service The text message "Book time for service" is shown when any of the following conditions is fulfilled: 1, 250 km (777 miles) before distance condition for service interval. 1 month before time condition for service interval. 100 hours before engine time condition for service interval.
2. time for service The text message "Time for service" is shown when any of the conditions for service interval is fulfilled. The service interval is dependent on model, engine, and market, and thus it varies. An example of condition for a service interval may be: Distance condition - 15, 000 km. Time condition - 12 months. Engine time condition - 750 hours.
3. Time for service exceeded The text message "Time for service exceeded" is shown when any or several of the conditions for service interval are fulfilled, and any of the following conditions is fulfilled: 1, 250 km (777 miles) after distance condition for service interval. 1 month after time condition for service interval. 100 hours after engine time condition for service interval.

The service message continues to be shown every time the ignition is turned on, until maintenance service is done and the service message has been erased.

The conditions for showing the service message can be programmed according to three different parameters

1. Distance condition - Driving distance.
2. Time condition - Number of months since last service.
3. Engine time condition- Number of hours engine has been running.

The engine oil's quality also has an impact on when the service message is shown. However, this parameter cannot be programmed.

Note. The service message may vary depending on market and/or language.

Resetting the service message

The service message can be reset using VIDA (Volvo scan tool) or as follows

1. Turn the key to position I
2. Press the reset button for the trip odometer. Turn the key to position II within two seconds
3. Hold the button pressed down until the information lamp begins to flash
4. Release the button.

Scheme 711

The engine control module (ECM), (4/46) processes the value it receives from the engine coolant temperature (ECT) sensor. The processed value is then transmitted to the central electronic module (CEM) (4/56) on the high speed section of the control area network (CAN). The central electronic module (CEM) receives the signal and generates a corresponding signal on the low speed section of the control area network (CAN). The driver information module (5/1) reads the signal from the low speed section of the control area network (CAN). The driver receives information about the temperature from the engine coolant temperature gauge in the combined instrument panel. A red lamp lights if the value is too high. A text message with explanatory information is also displayed.

PARKING BRAKE

The sensor for the parking brake is directly connected to the central electronic module (CEM). A signal which indicates whether the parking brake is applied or not is transmitted from the sensor to the central electronic module (CEM) (4/56). The central electronic module (CEM) sends the signal on to the driver information module (DIM) (5/1) via the controller area network (CAN). When the parking brake is applied (activated) the lamp lights.

The driver information module (DIM) can be programmed so that the driver is also warned by an audible signal that the parking brake is activated.

Scheme 712

The supplementary restraint system (SRS) (4/9) contacts the driver information module (DIM) (5/1) if there is a problem in the system. A signal is transmitted via the control area network (CAN) and the driver information module (DIM) lights the SRS lamp and displays a text message. The driver information module (DIM) also informs the supplemental restraint system module (SRS) whether the indicator lamp is working or not. A text message is displayed and the red warning lamp lights if the SRS warning lamp is not working.

BRAKE WARNING LAMP

The brake control module (BCM) (4/16) informs the driver information module (DIM) (5/1) if there is a fault in the brake system. The driver information module (DIM) informs the driver by lighting warning lamps and also displaying a text message. The signal is transmitted from the brake control module (BCM) (4/56) to the central electronic module (CEM) on the high speed section of the control area network (CAN). The central electronic module (CEM) transmits the signal onwards on the low speed section of the controller area network (CAN) to the driver information module (DIM).

The brake fluid level sensor detects the level of the brake fluid in the reservoir. The switch in the sensor closes again when the level is low. A signal is then transmitted on the controller area network (CAN) to the driver information module (DIM) which lights the red warning lamp and the brake warning lamp. The driver information module (DIM) also displays a text message.

FUEL GAUGE

There is sensor in the fuel tank, in some cases two. These transmit signals about the actual fuel level to the central electronic module (CEM) (4/56). The central electronic module (CEM) sends the signals on to the driver information module (DIM) (5/1). The driver information module (DIM) receives the signals, interprets them and displays the actual fuel level in the fuel gauge.

The low fuel level warning lamp lights when the fuel level is low. The warning lamp informs the driver that the fuel level is low. The warning lamp lights when there has been less than nine liters of fuel in the tank for 45 seconds.

The fuel gauge is not sensitive to rapid change. This is to prevent incorrect values being displayed when cornering or driving on slopes for example.

Scheme 713

The speedometer displays the actual speed the car is traveling at.

Information about speed comes from the speed sensor which is connected to the brake control module (BCM) (4/16) and the transmission control module (TCM) (4/28). The brake control module (BCM) and the transmission control module (TCM) calculate an average speed based on the signals sent from the two front wheels by the speed sensors. The calculated speed signals are then sent to the central electronic module (CEM) (4/56) from the brake control module (BCM) and the transmission control module (TCM) on the high speed section of the controller area network (CAN). Depending on the quality of the signal, the central electronic module (CEM) uses the signal from the brake control module (BCM) or the transmission control module (TCM). The central electronic module (CEM) then sends this information on to the driver information module (DIM) (5/1) which displays the speed.

Transmission control modules (TCM) are only installed in cars with automatic transmissions. In cars with manual transmissions, the speed signal is sent to the central electronic module (CEM) only by the brake control module (BCM).

TACHOMETER

A flywheel sensor is connected to the engine control module (ECM) (4/46). The engine control module (ECM) transmits the engine speed on the high speed section of the control area network (CAN). The central electronic module (CEM) (4/56) receives the signal and generates a corresponding signal on the low speed section of the control area network (CAN). The driver information module (DIM) (5/1) reads the signal and displays the engine speed for the driver.

Scheme 714

Engine control module (ECM) (4/46) checks the vehicle speed in relation to the current gear. The value is sent to the Central electronic module (CEM) (4/56) and on to Driver information module (DIM) (5/1).

In the lower information display in the Driver information module (DIM), an arrow appears at the most appropriate time to change up or down.

WARNING LAMP FOR LOW OIL PRESSURE (ONLY APPLIES TO VERSIONS WITH OIL PRESSURE SENSOR)

The oil pressure sensor is connected to the engine control module (ECM) (4/46). The engine control module (ECM) transmits the oil pressure signal onwards via the high speed section of the control area network (CAN). The central electronic module (CEM) (4/56) receives the signal and generates a corresponding signal on the low speed section of the control area network (CAN). The driver information module (DIM) (5/1) receives the signal. If the oil pressure is low, the driver information module (DIM) lights a red warning lamp to warn the driver. Explanatory information is also displayed as a text string.

HINT: In vehicles with an oil level sensor, the general warning lamp comes on and a text message appears when the oil level is too low.

GENERAL RED WARNING LAMP

This function displays different "faults" in the car. When a lamp lights this is followed by a text message that presents the driver with additional information about why the lamp has lit. The red warning lamp lights in the event of serious faults that affect driveability.

YELLOW INFORMATION LAMP

This function displays information. When a lamp lights this is followed by a text message that presents the driver with additional information about why the lamp has lit. The yellow information lamp lights when there is information of a less serious nature.

MALFUNCTION INDICATOR LAMP (MIL)

The malfunction indicator lamp (MIL) only lights in the driver information module (DIM) (5/1) if certain specific emissions related diagnostic trouble codes (DTCs) are stored in the engine control module (ECM) (4/46) or transmission control module (TCM) (4/28). A text message is also displayed when the lamp lights. The signal between the driver information module (DIM) and engine control module (ECM) is directly connected.

Scheme 715

The most important role of the driver information module (DIM) is to display the status of the vehicle systems for the driver. This covers functions such as

1. the vehicle speed
2. engine speed (RPM)
3. fuel level
4. engine coolant temperature (ECT)
5. various warning signals.

The control module is integrated in the combined instrument panel. If the control module is replaced, the combined instrument panel must also be replaced.

The driver information module (DIM) communicates with other control modules and components via CAN communication. However some functions are connected directly.

The control module checks the input and output signals through an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if the control module detects an error. In certain cases the control module replaces the faulty signal with a substitute value.

Any diagnostic trouble codes (DTCs) are stored in the control module memory. The data can be read off using VIDA (Volvo scan tool).

An easy way of checking that the driver information module (DIM) is both powered and grounded is to check whether the following warning lamps come on when the ignition is switched on

1. parking brake
2. malfunction indicator lamp (MIL) and
3. brake fluid level.

For further information, see SIGNALS .

The following table summarizes input and output signals to and from the driver information module (DIM). The signal types are divided into directly connected signals and Controller area network (CAN) communication. The illustration below (Scheme 716) displays the same information with the Volvo component designations.

Scheme 716

Scheme 717

The electrically convertible hardtop has a link system to which the front (1), center (2) and rear (3) roof sections and the parcel shelf (4) are connected.

The main links arms (5) are connected to the body at the rear edge. The center roof section is fixed to the main link arms. The front roof section sits on link arms (6) that are articulated to the main link arms. The rear roof section is also fastened to link arms (7) that are articulated to the main link arms.

The movement of the center and rear roof sections is generated by the link arms being actuated by two hydraulic cylinders known as the master cylinders. The movement of the front roof section is generated by two other hydraulic cylinder, known as the front roof cylinders.

The convertible roof module (CRM) regulates roof operation.

Scheme 718

The trunk lid consists of an upper section (1) and a lower section (2), each of which is moveably secured to a hinge (7).

The trunk lid can be opened in two ways, partly like a normal trunk lid, guided by hinges (6) and partly in the opposite direction, guided by hinges (7). The latter for when the roof is opened and closed. An electric catch motor (5) locks the upper section of the trunk lid in the catches (4) when the roof is not being operated.

Scheme 719

1. Catch, front roof section
2. Catch, center roof section
3. Catch, rear roof section
4. Catch, rear roof section, car body side
5. Catch, trunk lid
6. Lock pins, for open roof

1. There are two latches located under the front edge of the front roof section. When the roof is closed, the two latches (A) lock the front roof section against the windshield frame. This is done with the help of the front roof lock cylinder.
2. Two latches (B) lock the rear edge of the front roof section to the front edge of the center roof section. This is done with the help of the two roof cylinders (C).
3. Two rods (D) lock the rear edge of the center roof section to the front edge of the rear roof section. This is done with the help of the two roof cylinders (C).
4. Two catches (E) lock the rear edge of the rear roof section to the body when the roof is closed. Locking occurs via the two lock cylinders for the rear roof.
5. Two catches (F) are attached on the trunk lid's link system. These catches lock the upper section of the trunk lid in the link system, when the roof is open or closed. The lock catch motor operates these catches via cables.
6. When the roof is open (in the cargo compartment) the front section of the roof is operated through the movable mounting bracket (G). When the roof is in the correct resting position, the front roof section's lock cylinder locks the front catches (A) around the lock pins (H).

Lock, trunk lid

The trunk lid has an electric lock that locks the lid to the sill. The lock is fitted with a mechanical cable and a mechanical lock cylinder that can be used to open the trunk lid if the voltage to the lock is cut.

The lock cylinder for emergency opening of the trunk lid is placed

Model year 2006 and early versions 2007

Scheme 720

In the compartment between the front seats in the passenger compartment.

Later version 2007

Scheme 721

On the left-hand front edge of the rear seat.

Scheme 722

1. Cover panel, roof closed
2. Cover panel, roof open
3. Hydraulic cylinder

The cover panel is secured to the inside of the trunk lid. It slides forward to the rear seat backrest when the roof is open. The cover panel then closes against the trunk lid and to the backrest.

With the roof closed, the cover panel is in its drawn in position and located under the upper section of the trunk lid. When operating the roof, the cover panel is in its extended position.

The cover panel moves via a link system that is operated by two hydraulic cylinders.

The cover panel is not designed to be sat on.

Scheme 723

The cargo compartment contains several securing/stabilizing points for the stored roof

1. Four rubber spacers (1 and 2) on the floor of the cargo compartment just inside the sill.
2. Two moveable clamps (3) with locking pins are housed in the plate at the backrest. The latches of the front roof section engage in the locking pins and the clamps grip the front edge of the front roof section.
3. Two cradles (4), one on each side in the cargo compartment. The link system is secured in these when the roof is open.

Scheme 724

1. Two rubber pads (5) on the upper section of the trunk lid limit the movement of the upper section of the roof and prevent the roof section from colliding with various trunk lid components and the like.
2. Two rubber spacers (6) on the inside of the cargo compartment to support the window.
3. Two arms (7) ensure correct movement of the roof during the final phase of roof opening.
4. Two rubber heels (8) prevent the rear section of the roof from colliding with the front section during large roof movements.

Scheme 725

1. Lock cylinder, front roof
2. Roof cylinder, left
3. Roof cylinder, right
4. Main cylinder, left
5. Main cylinder, right
6. Lock cylinder rear roof, left
7. Lock cylinder rear roof, right
8. Cylinder tonneau cover, left
9. Cylinder tonneau cover, right
10. Cylinder trunk lid, left
11. Cylinder trunk lid, right
12. Hydraulic pump
13. Splitter box, hydraulic hoses

The hydraulic system consists of

1. hydraulic pump
2. 4 hydraulic valves
3. 11 hydraulic cylinders
4. 1 Splitter box

All hydraulic cylinders are dual-acting cylinders with single-sided piston rod. The hoses are attached with quick-release couplings.

The hydraulic cylinders operate the various roof functions independently and in pairs.

Hydraulic fluid is distributed from the splitter box to the hydraulic cylinders for the tonneau cover and the cargo compartment.

Hydraulic unit

Scheme 726

1. Electric motor that drives the hydraulic pump
2. Housing
3. Fluid reservoir
4. Relief valve
5. Lock for relief valve
6. Electrically operated hydraulic valve (x4)
7. Cable for release of relief valve lock
8. Hydraulic hoses

The hydraulic unit is located in the cargo compartment underneath the ski hatch. The convertible roof module (CRM) regulates the electric motor that drives the hydraulic pump clockwise or counterclockwise. The direction of rotation depends on the sequence/position of the roof during opening/closing.

The housing contains ducts through which the fluid passes to/from the hydraulic pump, to/from the four electrically controlled hydraulic valves, to/from the hydraulic cylinders and to/from the fluid reservoir.

The four hydraulic valves are integrated in the hydraulic unit and are directly connected to the convertible roof module (CRM). The various positions of the hydraulic cylinders (and thereby the positions of the roof sections) are regulated by opening/closing the valves in different patterns.

The relief valve releases pressure in the system when it is lifted. The ducts with pressure are then connected to the return ducts, whereby system pressure drops. Before the valve can be lifted, the lock (5) must first release the valve. This is done by pulling the cable. The handle of the cable is located under the rear seat cushion.

The hydraulic hoses are fitted in the housing with O-rings as seals. The hoses are secured with a screw. The hoses and housing have numbering to facilitate identification.

The hydraulic unit is enclosed by a casing to reduce noise from the pump.

Hydraulic cylinders

Scheme 727

1. Lock cylinder, front roof
2. Roof cylinder, left
3. Roof cylinder, right
4. Main cylinder, left
5. Main cylinder, right
6. Lock cylinder rear roof, left
7. Lock cylinder rear roof, right
8. Cylinder tonneau cover, left
9. Cylinder tonneau cover, right
10. Cylinder trunk lid, left
11. Cylinder trunk lid, right
12. Hydraulic pump
13. Splitter box hydraulic hoses

A = Open

B = Closed

All hydraulic cylinders are double acting cylinders with single side pistons. The piston/cylinder diameter, stroke length and mounting differ depending on task.

Roof cylinders

The two roof cylinders open/close the front roof section. In addition, the roof cylinders lock the front roof section to the center roof section and the center roof section to the rear section.

The locking sequence is carried out after the roof closes and the unlocking sequence occurs before the roof starts to open.

Locking occurs by the lugs on the hydraulic piston engaging in a cut-out on the locking mechanism plate. This causes the catches to follow the piston movement, where the front roof section locks into the center roof section. A ball joint is secured to the plate, opposite the catches. A push rod is connected to the ball joint. When the locking mechanism's plate moves, the push rod also moves (as do the catches). The push rod then engages in the lock housing for the rear roof section whereupon the center roof section is locked to the rear roof section.

The sequence is reversed when unlocking. i. e. the roof sections are first released and then the front roof sections opens.

The lock cylinders for the front roof section, lock cylinders and cylinders cover panel.

These cylinders move on bearings at both the cylinder and piston through ball joints. The design means that the load on these cylinders is relatively small.

Master cylinders

The master cylinders close/open the center roof section directly via the main link arms and the rear roof section indirectly via its link arms.

The movement and geometry of the link system when opening and closing the roof, cause the pistons to move elliptically. The master cylinders are suspended to prevent breaks and stresses.

Cylinders, trunk lid

The cylinders for the trunk lid are exposed to relatively large forces and are therefore strongly dimensioned. The cylinders move on bearings via bolts at both the piston and cylinder.

Connection of the hydraulic hoses to the pump

Scheme 728

F1 - F4 = hydraulic valves.

Connection of the hydraulic hoses to the splitter box

Scheme 729

Scheme 730

There is a divider (1) in the cargo compartment that can divide the cargo compartment into two sections. An upper section where the roof is stored when it is open and a lower section for storing luggage. Two gas struts (2) hold the divider in place.

The divider must be completely folded out for the roof to be opened.

There is a load assistance system for accessing the cargo compartment under the stored roof. The hydraulic system raises the stored roof slightly, which facilitates loading any loose luggage.

The switch for the load assistance system is located on the right-hand side of the trunk sill.

INTERNAL ROOF

The headlining consists of two main sections plus flexible fabric surfaces that cover the C-post when raised. The front headlining is fixed to the front section of the roof panel with clips and plastic screws. Moveable cover panels are secured to the front headlining along the side edges with hinges (2 per side). These are operated via wires.

The rear headlining is fixed to the center section of the roof panel with clips. Moveable cover panels are secured to the rear headlining along the side edges with hinges (3 per side). These are operated via wires.

Cables run along the right and left side edges of the headlining. The cables are screwed in place at the front and rear of the link arms. The cables are also fastened with screws along the link arms. The cables pull the moveable cover panels and fabric surfaces along the C-post to the correct position when the roof is operated.

The parcel shelf is only active when the roof is folded up. It is attached to the main mechanism and is folded away when the roof is lowered.

Each roof section has separate roof headlining.

The headlinings for the front and center roof sections have moving flaps. The flaps are attached in the spring loaded hinges, these, in turn, are attached in the front and center roof sections. Between the flaps and roof headlining's middle section is an area of headlining that is elastic.

When the roof is opened the headlining is folded inwards, which provides necessary space for the movement of the link system.

The movement of the flaps is controlled by a number of wires and spring loaded hinges. The wires and the spring loaded hinges help to guide the roof headlining to the correct positions when opening/closing the roof.

Cables

Scheme 731

The wire runs along the headlining's right and left edges. The wires pull the headlining to the correct position when the roof is closed.

The cables consist of three cable groups marked A, B and C in the illustration.

Cable A consists of cables A1, A2 and A3.

1. A1. "Front headlining" runs between points 1 and 3.
2. A2. "Center headlining" runs between points 2 and 5.
3. A3. "Upper section of C-post" runs between points 2 and 7.

Cable B runs between the C-post bracket and the mounting of the electrically convertible hardtop, between points 8 and 12.

Cable C runs between points 9 and 11.

Points that have both a sliding knot and mounting are the same component.

READING OFF EXTENDED FAULT-TRACING INFORMATION

This function can be used to read parameters, status identifiers and counters stored at the same time as a diagnostic trouble code (DTC). These are called frozen values.

Software downloads normally take place during manufacture of the car. However they are also required when replacing control modules.

When ordering software, the hardware and the software in the car is compared to the information in the Volvo central database. If the comparison is OK the software is downloaded to the control module.

If the comparison between the car and Volvo central database is not OK, the database is updated with the car configuration. When this is complete the software is downloaded.

If the power to the electrical power steering module (EPS) is cut, no new software download is required, as long as the software was previously loaded correctly into the control module.

When replacing the electrical power steering module (EPS), new software must be downloaded into the new module. New software must be downloaded because the software is optimized for the profile of the car.

Note. A diagnostic trouble code is stored if the software is not downloaded to a new control module, and the power steering function will not correspond to the profile of the car.

Scheme 732

1. Hydraulic fluid, pressure side
2. Hydraulic fluid, return side.

When the electrical power steering module (EPS) receives a 15 supply via the ignition switch which "wakes up" the control module. This is to diagnose certain functions and to prepare to start the pump motor. When the engine is started, the control module will activate the pump motor in the system so that the power steering function is activated.

The following is measured when the driver turns the wheel

1. steering angle speed
2. the vehicle speed
3. maximum permitted power consumption
4. engine status (engine running).

These input signals, together with the internal signals (pump motor speed, temperature in the control module, power consumption of the pump motor etc) are used by the control module to control and diagnose the electro hydraulic power steering. This gives optimal power steering adaptation.

The control module controls the power consumption of the pump motor using the internal power stage. For efficient control of the pump motor, a pulse width modulated supply is used. By controlling the pulse ratio, the control module is able to regulate the output of the pump motor and therefore the speed which indirectly controls the hydraulic pressure in the power steering system. Principally the control module continuously monitors the following

1. the power consumption of the pump motor
2. the speed (RPM) of the pump motor
3. the temperature in the control module.

This means that the system is regulated constantly so that the hydraulic pressure is correct. The functionality of the system can also be diagnosed efficiently.

Scheme 733

The steering wheel module (SWM) (3/254) informs the electrical power steering module (EPS) (4/99) about the actual steering wheel angle speed via the controller area network (CAN). This allows the electrical power steering module (EPS) to calculate the optimum desired value for the pump motor speed for optimum steering assistance, irrespective of the speed of steering wheel movements.

Scheme 734

While driving, the brake control module (BCM) (4/16) registers the acceleration and deceleration of the wheels. The 4 wheel sensors (7/31-32 and 7/56-57) (one on each wheel) provide the brake control module (BCM) with information about the rotation speed of each wheel. The brake control module (BCM) calculates the actual speed of the car using this information and puts it out on the controller area network (CAN). The vehicle speed signal is used by the electrical power steering module (EPS) (4/99) so that, when combined with other parameters, it can calculate the optimal desired value for the pump motor speed. The system reduces the speed of the pump motor (reduced hydraulic pressure) when the vehicle speed increases. The pump motor speed increases (increased hydraulic pressure) as vehicle speed drops. This to obtain optimal steering assistance in relation to vehicle speed. This is speed dependent power steering.

Scheme 735

The engine control module (ECM) (4/46) provides information about engine status and engine speed via the controller area network (CAN). This information is used to activate the pump motor when the engine is started.

Vehicles equipped with the function automatic start/stop of engine will also use the information from Engine control module (ECM) and Central electronic module (CEM) (4/56) to decide if the vehicle is in position autostop.

If the vehicle is in position autostop, the pump motor will be deactivated. The pump motor is reactivated when the engine is started again.

Scheme 736

If a fault is registered (certain diagnostic trouble codes (DTCs) only), the electrical power steering module (EPS) (4/99) will inform the central electronic module (CEM) (4/56) that there is a fault in the power steering system via the controller area network (CAN). The central electronic module (CEM) then transmits a request via the controller area network (CAN) to the driver information module (DIM) (5/1) to light the information lamp and to activate a text message in the display. The text message informs the driver that there is a fault in the power steering system. When the fault has been remedied, a request is transmitted in the same way to switch off the information lamp and deactivate the text message.

Scheme 737

The power steering system is electro hydraulic and governed by the electrical power steering module (EPS). The control module regulates the power steering assistance based on input signals. This allows it to provide optimal steering assistance, irrespective of whether the vehicle is stationary with the engine running or is being driven at high speed. The functions managed by the electrical power steering module (EPS) are active when the engine is running.

The control module is under the right-hand headlamp. The control module and pump motor make up a single replaceable unit.

The electrical power steering module (EPS) is powered by the battery (30 supply) via a fuse in the integrated relay/fusebox in the engine compartment. The electrical power steering module (EPS) receives a 15 supply via the ignition switch and is unfused in the integrated relay/fusebox in the engine compartment and in the central electronic module (CEM). The electrical power steering module (EPS) is grounded in the left-hand suspension turret via a ground lead.

The electrical power steering module (EPS) communicates with other control modules using controller area network (CAN) communication.

If replacing the electrical power steering module (EPS), software optimized for the profile of the car must be downloaded into the control module. If this is not done, although the power steering will function, it will not be optimized to the profile of the car.

The table below summarizes the input signals to and output signals from the electrical power steering module (EPS).

The signal types are divided into directly connected signals and Controller area network (CAN) communication. The illustration below (Scheme 738) displays the same information with the Volvo component designations.

Scheme 738

Scheme 739

The entire engine is made of aluminum.

The compact "pent roof" design of the combustion chamber and the V shaped arrangement of the valves optimize injection and evacuation via the intake passage and combustion chamber (cross-flow) and the exhaust passage. The swirl surfaces of the combustion chamber and the centrally positioned spark plug ensures optimal combustion, low sensitivity to knocking and low, stable exhaust emissions.

The pendulum suspension of the engine consists of an engine pad secured to a side member. The cylinder head is "gravity" cast which is a slower process than press casting. This is so that the exhaust and intake ducts and the water and oil mantles are integrated during construction.

Applies from 2006 model year

The engine meets Euro 5 emissions standards.

All bearings are lead free. The screws used are Crome 6+ free.

Scheme 740

The engine block is divided up into five sections. The cylinder head consists of two sections and the cylinder block of three sections. The seal between the cylinder head and cylinder block is a conventional cylinder head gasket. The seal between the other gasket faces is a liquid gasket.

There is a cover over the sparkplug wells for protection against dirt and water. The two camshafts are carried on six bearing caps each in the two halves of the cylinder head. The upper half is a combined valve and camshaft cover.

It has cast oil ducts on the underneath which ensure good oil supply to the camshafts and the mechanical valve lifters. The lower half contains the maintenance-free mechanical valve lifters, the valve springs and valves.

Scheme 741

The engine block is divided into three sections, the cylinder block, intermediate section and oil pan. The mating flange between the cylinder block and intermediate section is in the center line of the crankshaft.

The cylinder block has five cast iron cylinder sleeves cast into the cylinder block which cannot be replaced. The six main bearing seats have cast iron reinforcements in the intermediate section.

On the top of the intermediate section there are cast oil channels which distribute the oil to the main bearings and on via the crankshaft to the big ends.

The oil pan contributes to the rigid construction and acts as additional reinforcement. There is central smooth-bore oil duct for piston cooling.

Scheme 742

The oil pan is made of die cast aluminum with baffles. This is so that the oil does not splash excessively. It is secured in the cylinder block with a liquid LOCTITE gasket, which ensures the seal between the cylinder block and oil pan.

Scheme 743

The crankshaft has six main bearings. The 5th main bearing is a throw-out bearing. At the front end of the crankshaft are two spline joints, the inner of which drives the oil pump. The drive gear for the timing belt and vibration damper is on the outer joint.

A blind spline ensures that the position and control of the drive gear is correct. The connecting rods are forged and the split joint between the connecting rods and the caps gives an exact mounting to the caps.

B5244SX and B5254TX are both equipped with forged crankshafts which give maximum strength and contribute to a low noise level.

PISTON

The piston has a homogenous aluminum alloy with graphite coating on the sides. This coating gives reduced friction and noise. The piston rings are of different materials depending on where they are located on the piston. The upper compression ring is a nitrated steel ring. The lower compression ring is manufactured from cast iron and the oil scraper ring is a three piece design, all made of nitrated steel (does not apply to B5xx4Sx). For B5244S7 engines the oil scraper ring is two piece instead of three piece. It is more wear resistant than the three piece ring. The ring height is 2.5 mm compared to 2.0 mm for the three piece ring.

The piston pin is hardened steel and is held together using steel snap rings. The piston is oval and conical and flat at the top. By reducing the area from the upper piston ring to the top of the piston, the release of hydro-carbons from the engine to the three-way catalytic converter (TWC) is reduced.

The pistons are oil cooled so that they can have a lower compression height. Oil is led through a valve in a longitudinal channel in the lower section of the cylinder block on the exhaust side. There is a nozzle screwed to the channel at each cylinder. This leads the oil towards the underside of the piston.

Scheme 744

The camshafts are cast iron. The cam lobes which press against the valve lifters are hardened to tolerate the contact pressure. The valve lifters are steel and mechanical, not hydraulic.

There is a certain amount of valve clearance between the valve lifters and cam lobes. The valve clearance is adapted to compensate for differences in length between the valve and cylinder head due to expansion when warming up. Mechanical valve lifters ensure more precise valve timing, reduced friction, more stable combustion and reduced mass.

The material in the lifters is case-hardened steel. The surfaces between the camshaft and valve are slightly convex to guarantee centered contact.

Scheme 745

The timing belt which drives both the camshafts and the coolant pump is a conventional single tooth belt. The camshaft's pulley wheels are secured by three screws in each camshaft. The holes for the screws are oval to allow the correct setting of the camshaft positions.

The timing belt tension is retained by a mechanical belt tensioner. The belt tensioner presses the belt via a tensioner roll installed on a lever. The idler wheel on the other side of the belt prevents the belt from swinging.

Scheme 746

The auxiliary equipment consists of two belts and two auxiliary units. The auxiliary units (generator (GEN), Air conditioning (A/C) compressor) are driven by two Poly-V drive belts tensioned by a mechanical tensioner. The belt tensioners are all located on a bracket that connects the auxiliary units (generator (GEN), Air conditioning (A/C) compressor).

The generator (GEN) receives its power via the air conditioning (A/C) compressor and the air conditioning (A/C) compressor receives its power through the vibration damper which is located on the crankshaft. The power steering pump is driven by an electrical hydraulic pump.

Scheme 747

The tensioner consists or a spring and a friction element. The friction element provides the required damping to absorb small oscillations and speed variations. The spring ensures correct belt tension, irrespective of wear and temperature. The belts are made of cord reinforced rubber.

Scheme 748

The oil is led from the oil pan via a suction piece to the oil pump. The oil pump is located on the cylinder block. The oil is then pumped onwards to the oil cooling system and then to the oil filter. The oil flows from the filter through a cast oil duct in the intermediate section to the main bearings. The oil then flows through drilled channels in the crankshaft to the connecting rod bearings.

The camshafts are supplied with oil by a bored channel in the cylinder block. The channel runs through the cylinder head, where it flows out at the bottom of the upper half of the cylinder head. There is a cross duct in the channel to the cylinder head which carries oil to the pistons via a piston cooling valve.

The oil flows on via an oil duct to the bearing for the left-hand camshaft and the valve lifters (intake side). The bearings for the right-hand side camshaft (exhaust side) are supplied by a cast cross duct at the front edge of the upper half. This cast cross duct also supplies pressurized oil to the solenoids for the VVT unit. Drain holes in the cylinder block release the oil from the cylinder head and crankshaft bearing back to the oil pan.

Scheme 749

The oil filter holder is made of die cast aluminum. It is on the cold side of the engine. The oil filter cover is plastic. There is a by-pass valve in the cover. A O-ring in the cover ensures that it is sealed.

Scheme 750

The piston cooling valve is manufactured in steel with a hardened piston, a spring and a spring stop. A copper washer ensures that oil does not leak onto the cylinder block.

INJECTOR

The valve is enclosed in a plastic casing with O-rings on each end which act as seals. There is a coil in the valve which creates a magnetic field. This overpowers the force of the spring which holds the fuel needle in place. The fuel is let through and mixes with the intake air.

EVAPORATIVE EMISSION (EVAP) SYSTEM

The housing for the evaporative emission system (EVAP) valve is plastic and contains a solenoid valve. The evaporative emission system (EVAP) canister consists of a plastic holder with active carbon and a filter. Internally, the plastic holder is divided up into chambers depending on the market and the prevailing emissions requirements.

All the active carbon in the canisters is held by springs and pressure plates so that no air columns are created by vibration for example. This could lead to hydrocarbon leakage at the carbon beds. The connector pipe has a filter so that carbon dust cannot leak out and damage the leak diagnostic pump and the EVAP valve.

The leak diagnostic pump consists of a plastic housing with an electric motor, pump, valves, leak calibration and a PTC heater element.

Scheme 751

The intake system is divided into two sections, the upper and lower intake manifolds. The upper intake manifold is made of plastic for naturally aspirated and turbocharged engines. The lower intake manifold is aluminum for both types of engine to protect the fuel injection nozzles in the event of a collision.

The intake system for naturally aspirated engines has a total volume of 5.3 liters with fixed barrel lengths. On turbocharged engines the total volume is 3.0 liters with short barrels.

The gasket between the lower intake manifold and cylinder head on naturally aspirated engines is a calibrated single gasket. On turbocharged engines there is a double gasket with a built in non-return valve.

Scheme 752

The throttle body (TB) is die cast aluminum. The throttle disc is brass on naturally aspirated engines and aluminum on turbocharged engines. The position sensors are under the plastic cover. These read the position of the throttle disc. There are also two connections to the engine in the cover. These turn the throttle disc to the angle requested by the driver.

The throttle body (TB) does not need to be cooled, but may need to be heated. An O-ring in the intake manifold ensures the seal between the intake manifold and throttle body (TB).

Scheme 753

The integrated manifold and turbine housing are made of austenite forged steel to tolerate exhaust temperatures up to 1050 °C.

The bearing housing and turbine housing are held together by a V-shaped clamp. The compressor housing is made of die cast aluminum. The bearing housing is cooled by the oil and coolant system to prevent coking in the bearing for the turbine shaft which spins at up to 170, 000 RPM.

Scheme 754

The exhaust system primarily consists of four sections. Manifold (and turbocharger (TC) if the engine is turbocharged), three-way catalytic converter (TWC), heated oxygen sensors (HO2S) and muffler. The exhaust system is manufactured from chromium steel sections welded together.

The pipes are specific lengths so that the gases flowing from the cylinders do not interfere with each other and so that there is good flow distribution in the three way catalytic converter (TWC). There is a boot on the three way catalytic converter (TWC) to absorb engine movements and any manufacturing and installation tolerances.

Heated oxygen sensors (HO2S) are used to control the engine and monitor the three way catalytic converter (TWC). One heated oxygen sensor (HO2S) before and one heated oxygen sensor (HO2S) between the stones. In the B5244S7 an additional heated oxygen sensor (HO2S) is located in the manifold.

The entire exhaust system is manufactured in chromium steel. A three-way catalytic converter (TWC) consists of perforated ceramic beads or metal substrates. These are coated with a washcoat. The washcoat contains precious metals among other things.

FLAME TRAP

The flame trap is made of die cast aluminum and integrated with the oil filter. The cyclone separators are plastic and cannot be replaced.

Scheme 755

The coolant pump pumps coolant through the cylinder block, and also cools the cylinder head, cylinder sleeves, spark plug wells, intake ducts and fuel injection nozzles.

The coolant flows in at the pump and passes through a number of channels before it collects and then flows out to the thermostat housing. If the thermostat housing is closed, the coolant passes via the by-pass channel directly to the coolant pump to then circulate through the cylinder block again.

In principle, its appearance is the same as the oil cooler for the transmission. Both have an inlet and outlet. The oil cooler is constructed in layers where water and oil flow around each other. Having flowed through the restrictions in the oil ways, the pressure in the system falls.

When the fuel combusts in the engine, the result is both mechanical work and excess energy. The excess heat is taken away from the engine via the exhaust gases by convection to the air in the engine compartment and also by transfer to the coolant and engine oil. The cooling system is a closed system.

B5244S6

Engine B5244S6 has a Premair sensor on the cooling system.

RADIATOR

The radiator is made of aluminum to tolerate the thermal variances when the radiator is being both cooled by cool air and heated by hot coolant.

THERMOSTAT

The thermostat is in the thermostat housing which is in the connection to the coolant outlet from the cylinder head. At the heart of the thermostat is a wax body which expands with energy in the form of heat. In modern cooling systems, the thermostat begins to expand when the surrounding coolant temperature is 90 °C.

OIL PAN

The main task of the oil pan is to be the reservoir for the oil. It is also part of the cylinder block. There are a number of components which are secured in or on the oil pan.

The oil level is checked via the dipstick which is connected to the oil pan. A suction pipe with a nozzle supplies the oil pump with oil which is then pumped onwards in the engine. To facilitate the suction function of the oil pump, there is a bleed valve which ensures that any air in the system is evacuated. The oil flows through the oil cooler to lower its temperature. The oil cooler is screwed to the outside of the oil pan.

Scheme 756

The function of the crankshaft is to transfer the upwards and downwards power of the piston movement. The engine is pendulum mounted, which provides better crankshaft balance than a non-pendulum mounted engine. The connecting rod, which is secured on the crankshaft, transfers the upwards and downwards movement of the piston into crankshaft rotation.

The main task of the piston is to compress the fuel/air mixture during the different strokes. The piston rings provide a seal so that the fuel/air mixture is not forced past the piston. The uppermost ring expands when the piston moves downwards. The second ring, as well as sealing is an oil scraper ring during the downward piston movement. The third ring ensures that the oil is drained via the drainage hole.

CAMSHAFTS, VALVE SYSTEM

The camshafts and valves let in the fuel/air mixture for the ignition stage. The camshafts and valves then release the fuel/air mixture after ignition.

Conical valve springs allow smaller shims to be used and reduce the total moving mass. The valve springs operate progressively. This means that there is little force at the beginning and the end of the closing phase, but considerable force during maximum valve lift.

The camshaft is rotated by the timing belt which is turned by the crankshaft. When the cam lobes on the camshaft press in the valve lifter, the valve is also pressed in and lets the fuel/air mixture out. A VVT unit on the camshaft can vary the valve timing steplessly using the oil pressure. The function of the VVT unit is to determine when to open or close the valves (within specific tolerances).

MECHANICAL BELT TENSIONER

The belt tensioner must maintain constant pressure on the timing belt and prevent the belt from jumping off the cogs.

OIL FILTER

The filter is an environment filter which filters out any dirt particles from the oil. The oil flow from the outside into the filter. If the filter becomes blocked, the by-pass valve opens so that the oil can pass the filter. This ensures that the engine is always lubricated with oil.

PISTON COOLING VALVE

The piston cooling valve regulates the oil flow by letting oil through the piston cooling nozzles.

Scheme 757

The oil pump pumps oil from the oil pan via channels in the intermediate section and cylinder block into the cylinder head and onwards in the system. The oil pump is on the end of the crankshaft. The crankshaft runs through the oil pump. A duo-centric gear wheel reduces the flow of oil, increasing the pressure. This results in a pulse action which forces out the oil. The oil can only flow in one direction.

The injector ensures engine performance in certain situations. The fuel comes from the fuel rail to the inlet for the injector and then through the injectors. The fuel is mixed with the intake air. The fuel/air mixture must be as homogenous as possible.

Scheme 758

The EVAP canister absorbs the hydro-carbons in the fuel vapors so that they are not released. The engine control module (ECM) controls the EVAP valve. The hydro-carbons are emptied from the EVAP canister when the valve is open. When emptying, the atmospheric air flows through the EVAP canister (where stored hydro-carbons are gathered) and on to the intake manifold and combustion chamber. The energy in the hydro-carbons is then used during the combustion process. So that emissions are not negatively affected, the EVAP valve is pulsed by a pulse width modulation (PWM) signal, the frequency of which is calculated by the engine control module (ECM).

The signals from the heated oxygen sensors (HO2S) are used as a reference. The EVAP valve is closed during the leak diagnostic. The leak diagnostic unit checks the gas and fuel filled sections of the EVAP system. Any leaks in the fluid filled sections cannot be detected. When the pump is not activated, it is open so that the fuel tank and EVAP system can "breathe".

A number of parameters must be met before the EVAP canister can be emptied. For example

the engine coolant has reached a certain temperature.

the fuel/air ratio is within the tolerance zones.

During leak diagnostics, the control module activates the pump and test pressurizes/calibrates the pump against a built-in leak scenario in the pump module. A valve then closes so that the pump motor can create overpressure in the tank and EVAP system. The control module is able to determine the size of the leak in the tank and EVAP system by measuring the power consumption of the pump in these two circumstances. If the current level is too low in relation to the level for the in-built leak scenario, there is leakage in the system. The built-in PTC heater element is used to prevent condensation in damp weather which could disrupt the leak diagnostic.

INTAKE SYSTEM

Each cylinder has an intake manifold which comes from a plenum chamber. The injectors are on the lower aluminum intake manifold close to the intake valves. This is so that the fuel mixes as well as possible with the turbulent air. The position of the injectors is optimized to minimize wetting the cylinder walls and therefore emissions. There are ducts in the lower intake manifold for the crankcase gases so that they can reach the combustion chamber.

Scheme 759

For B5xx4Sx

The air enters via the air intake on the front member. The air is routed via a cold air hose in the air cleaner (ACL) housing. Here there is also a snow valve. This valve opens if the air cleaner (ACL) housing and air intake are blocked by snow. This lets the air flow through and also uses cooling flanges to cool the engine control module (ECM). The air then flows through a funnel with a net which reduces air turbulence before the air reaches the mass air flow (MAF) sensor.

The mass air flow (MAF) sensor controls the mass air flow to the engine. The air then flows to the electrical throttle body (TB) and into the intake manifold. The manifold absolute pressure (MAP) sensor gauges the pressure in the intake manifold. The evaporative emission system (EVAP) valve recirculates the fuel/air mixtures for further combustion. The evaporative emission system (EVAP) valve is by the throttle body (TB). There is a direct terminal from the air cleaner (ACL) to the intake manifold which by-passes the mass air flow (MAF) sensor. There is a brake vacuum ejector in the middle of the hose. The brake vacuum ejector uses the pressure differences in the air cleaner (ACL) housing and plenum chamber to create a flow in the hose to create a vacuum in the brake booster.

Scheme 760

For B5xx4Tx

The air enters via the air intake on the front member. There is a rail in the air intake pipe which divides the pipe to minimize drops in pressure. The air then flows on to the air cleaner (ACL) housing. Here there is also a snow valve. This valve opens if the air cleaner (ACL) housing and air intake are blocked by snow. This lets the air flow through and also uses cooling flanges to cool the engine control module (ECM).

The air then flows through a funnel to the mass air flow (MAF) sensor. The mass air flow (MAF) sensor controls the mass air flow to the engine. The air then flows through a fresh air hose over the engine. The air then passes the turbocharger (TC) and charge air cooler before reaching the electronic throttle body (TB) and being released into the intake manifold. The evaporative emission system (EVAP) valve recirculates the fuel/air mixtures for further combustion. The evaporative emission system (EVAP) valve is by the throttle body (TB).

THROTTLE BODY (TB)

The throttle body guides the air flow into the intake manifold. The requested throttle disc angle is obtained by the driver by the accelerator pedal movement / accelerator pedal position. The intake air comes from the air filter housing through the throttle body and on to the intake manifold.

TURBOCHARGER (TC)

The exhaust gases enter the turbine housing via the manifold and then flow out to the exhaust system via the down pipe and three-way catalytic converter (TWC). The turbine expels the exhausts and rotates the compressor wheel. The compressor wheel creates a certain amount of suction using the intake air. This intake air enters the compressor via the air filter and uses a rotational movement to speed up the air, creating the boost pressure.

The air then continues into the intake system. The wastegate valve then controls the boost pressure in the turbocharger by determining the amount of exhaust gases which must pass the turbine to transfer drive to the compressor. The by-pass valve is a membrane which equalizes the pressure of the intake and exhaust air to eliminate noise.

EXHAUST SYSTEM

The three-way catalytic converter (TWC) acts by oxidizing carbon monoxide (CO) and hydro-carbons (HC) to water and carbon dioxide (CO 2 ). Nitrous oxides (NO x ) are reduced to nitrogen and water. Over 98% of these substances are converted in the three-way catalytic converter (TWC) during normal driving. Lead pollutants in the fuel damage the three-way catalytic converter (TWC) and can quickly render it unusable.

CRANKCASE VENTILATION

The crankcase ventilation controls the pressure in the crankcase. The crankcase gases are also separated in the flame trap and cyclone separators and favorable particles are returned to the engine.

The flame trap roughly separates the crankcase gases from the cylinder block. The crankcase gases circulate around the walls in the flame trap before entering the cyclone separators. The cyclone separators act on the crankcase gases to separate the particles/substances. The oil in the crankcase gas runs down into a container chamber to be returned to the oil pan. The rest of the crankcase gas is directed on to a pressure regulator which regulates the pressure in the crankcase. The crankcase gas is then evacuated from the pressure regulator to return to the intake manifold via the turbocharger on vehicles with turbocharged engines. Otherwise the gas returns directly to the intake manifold.

When the coolant temperature is high enough to partially open the thermostat, the coolant is distributed via the radiator and the bypass channel to the coolant pump. When the thermostat is fully open, all the coolant goes to the radiator. The cooled air is sucked through the radiator by an electric engine cooling fan (FC) on the fan shroud behind the radiator.

The thermostat regulates the amount of coolant to the engine. The wax body expands when energy reaches it in the form of heat. In modern cooling systems, the thermostat begins to expand when the surrounding coolant temperature is 90 °C.

When the wax body expands in the thermostat, a flow of coolant is allowed through the radiator while the flow to the by-pass is shut off to speed up cooling. Coolant routed through the bypass returns to the engine without being cooled. Any air is able to leave the system via a jiggle pin. The jiggle pin is in the thermostat.

Scheme 761

Engine B5254 is a 5 cylinder 20 valve turbocharged engine with a cylinder capacity of 2.5 dm 3 . Engine B5244 is a 5 cylinder 20 valve naturally aspirated engine with a cylinder capacity of 2.4 dm 3 .

Visually there is no different between the engines. The difference is in specific components which affect the turbocharger (TC) and natural aspiration. There are different transmission combinations for the engine. The 5 and 6 speed manual transmission are called M56 and M66. The automatic transmissions are AW55-51 and AW50AWD.

The engine and transmission are pendulum mounted. A mounting on the engine is linked via a rubber bushing to the side member and an engine mounting on the transmission.

see DESIGN

see FUNCTION

HEATED OXYGEN SENSORS (HO2S)

Front heated oxygen sensor (HO2S)

Scheme 762

The front heated oxygen sensor (HO2S) is used to provide the engine control module (ECM) with information about the remaining oxygen content of the exhaust gases in front of the three-way catalytic converter (TWC). This is so that the Engine Control Module (ECM) can continually check the combustion so that lambda=1. lambda=1 is the ideal fuel-air ratio, with 14.7 kg air per 1 kg fuel.

The heated oxygen sensor (HO2S) uses current control and its signal characteristic is linear. With a linear signal characteristic, the amplitude of the signal curve is low when the oxygen content in the exhaust gases changes. The probe consists of a preheating element and the actual lambda sensor. The lambda sensor is an oxygen sensitive ceramic body consisting of zirconium oxide. The control module supplies power to the ceramic body, which reacts to the oxygen content of the exhaust gases. This in turn affects the signal to the engine control module (ECM). In order to determine the oxygen content in the exhaust pipe, the heated oxygen sensor (HO2S) needs reference air from the surrounding air. This reference air reaches the heated oxygen sensor (HO2S) via the air lines.

The engine control module (ECM) can diagnose the heated oxygen sensor (HO2S). For more information, see: HEATED OXYGEN SENSOR (HO2S) DIAGNOSTIC

VIDA (Volvo scan tool) can be used to read off the calculated lambda value from the heated oxygen sensor.

Center heated oxygen sensor (HO2S)

Scheme 763

Some vehicles have 3 heated oxygen sensors (HO2S), front, center and rear.

The center heated oxygen sensor (HO2S) is the same type as the rear. However it has a different part number to differentiate it from the rear heated oxygen sensor (HO2S).

The center heated oxygen sensor (HO2S) is used

1. to provide the engine control module (ECM) with information about the remaining quantity of oxygen in the exhaust gases. This information is provided more quickly than in vehicles with only a front and rear heated oxygen sensor (HO2S)
2. to allow quicker start of exhaust purification
3. for regulation when the engine is under low loads.

The center heated oxygen sensor (as with the rear heated oxygen sensor (HO2S)) uses voltage control. The signal characteristic is binary. With a binary signal characteristic, the amplitude of the signal curve changes considerably when changing the oxygen content in the exhaust gases.

The engine control module (ECM) can diagnose the center heated oxygen sensor (HO2S). The signal can be read using VIDA (Volvo scan tool).

For more information, see HEATED OXYGEN SENSOR (HO2S) DIAGNOSTIC

Rear heated oxygen sensor (HO2S)

The rear heated oxygen sensor (HO2S) is used to provide the Engine Control Module (ECM) with information about the remaining oxygen content of the exhaust gases behind the three-way catalytic converter (TWC). This information is used by the Engine Control Module (ECM) to check the function of the three-way catalytic converter (TWC). This check is carried out when the conditions for the catalytic converter diagnostics have been met. The rear heated oxygen sensor (HO2S) has no direct effect on regulation of the fuel/air mixture. However the Engine Control Module (ECM) uses the signal to optimize the signal from the front heated oxygen sensor (HO2S). For more information, see: THREE-WAY CATALYTIC CONVERTER (TWC) DIAGNOSTICS

The heated oxygen sensor (HO2S) uses voltage control. The signal characteristic is binary. With a binary signal characteristic, the amplitude of the signal curve changes considerably when changing the oxygen content in the exhaust gases. Otherwise its components and function are the same as the front heated oxygen sensor (HO2S).

The engine control module (ECM) can diagnose the rear heated oxygen sensor. The signal can be read using VIDA (Volvo scan tool).

Preheating of the heated oxygen sensors (HO2S)

The heated oxygen sensor (HO2S) only functions above a certain temperature, approximately 300 °C. The normal operating temperature is between 300-900 °C. The heated oxygen sensors (HO2S) are electrically pre-heated so that operating temperature is rapidly reached. They are also pre-heated to ensure that the heated oxygen sensors (HO2S) maintain a normal operating temperature and to prevent condensation which could damage the heated oxygen sensor (HO2S).

The heater element in the probe consists of a positive temperature coefficient (PTC) resistor. The system relay supplies the heater element with voltage. The element is grounded in the engine control module (ECM). When the control module grounds the connection a current flows through the PTC resistor. When the heated oxygen sensor (HO2S) is cold, the resistance in the PTC resistor is low and a large current will flow through the circuit. The current from the Engine Control Module (ECM) is pulsed at first to prevent condensation damage to the heated oxygen sensor (HO2S). Depending on the temperature, allowances are made for factors such as the dew point. As the temperature in the PTC resistor rises, the resistance rises, the current falls and switches in stages to a constant current. The pre-heating time for the front heated oxygen sensor (HO2S) is short, approximately 20 seconds.

The heater element heats the heated oxygen sensors (HO2S) to approximately 350 °C. The probes maintain this as a minimum temperature.

The engine control module (ECM) can diagnose the heater element.

Scheme 764

The engine coolant temperature (ECT) sensor checks the temperature of the engine coolant. The temperature of the engine coolant is required so that the engine control module (ECM) can regulate

1. the injection period
2. the idle speed
3. the engine cooling fan (FC)
4. the ignition advance
5. engagement and disengagement of the A/C compressor
6. diagnostic functions.

The sensor is a negative temperature coefficient (NTC) type which is supplied with power from the control module (signal) and is grounded in the control module.

The resistance in the sensor changes depending on the temperature of the coolant. Depending on the resistance in the sensor, a voltage (signal) is transmitted to the Engine Control Module (ECM). The lower the temperature the higher the voltage (high resistance). A high temperature results in low voltage (low resistance).

The engine coolant temperature (ECT) sensor is located beside the thermostat.

The engine control module (ECM) can diagnose the engine coolant temperature sensor. The sensor value can be read off using VIDA (Volvo scan tool).

Scheme 765

Note. The engine cooling fan may have a post-run of up to approx. 6 minutes after the engine has been turned off. The time for the fan's post-run depends on engine temperature, temperature in the engine compartment and pressure level in the AC-system.

The engine cooling fan (FC) has two functions. One is to cool the engine compartment, the other is to cool the condenser when the air conditioning (A/C) compressor is working.

The engine control module (ECM) transmits a pulse width modulated (PWM) signal to the engine cooling fan (FC) control module. The control module then activates the fan at different speeds. The speed of the engine cooling fan (FC) is determined by the engine control module (ECM), depending on the coolant temperature (based on the signal from the engine coolant temperature (ECT) sensor) and the vehicle speed.

The temperature conditions for engagement of the different engine cooling fan (FC) stages may vary slightly, depending on the engine variant and the equipment level. The temperature conditions apply when

1. the A/C is off
2. no faults are detected by the Engine Control Module (ECM).

The engine cooling fan (FC) and its control module are behind the radiator.

The engine control module (ECM) can diagnose the engine cooling fan. The fan can be activated using VIDA (Volvo scan tool).

Scheme 766

Overview

The mass air flow (MAF) sensor on naturally aspirated engines is a combined sensor and contains two sensors in the same component

1. mass air flow (MAF) sensor
2. temperature sensor.

The mass air flow (MAF) sensor is positioned between the air cleaner (ACL) housing and the intake manifold.

Mass air flow sensor

The mass air flow (MAF) sensor gauges the air mass sucked into the engine. It continuously transmits signals to the engine control module (ECM) about the mass of the intake air. This data is used by the engine control module (ECM) to calculate

1. the injection period
2. the fuel pressure
3. the ignition timing
4. the engine load.

The transmission control module (TCM) also uses this data for its gear shift calculations. This data is transmitted to the transmission control module (TCM) from the engine control module (ECM) via the high speed side of the Controller area network (CAN).

The mass air flow (MAF) sensor is a hot wire type. Unlike other hot wire types, the mass air flow sensor in the Denso system uses a hot wire which has a ceramic casing. This eliminates the need for a clean burn function.

The mass air flow (MAF) sensor is supplied with battery voltage by the system relay and is grounded in the engine control module (ECM). The signal from the sensor is analogue and varies between approximately 0.5-4.5 V depending on the air mass. Low air flow (low mass) results in low voltage, high air flow (high mass) gives high voltage.

On turbocharged engines the mass air flow (MAF) sensor has a slightly different design. It is not a combined sensor and only contains sensors for the mass air flow.

The engine control module (ECM) can diagnose the mass air flow (MAF) sensor. The signal can be read using VIDA (Volvo scan tool).

Temperature sensor

The temperature sensor checks the temperature of the intake air in the intake manifold. This data is used by the engine control module (ECM) to calculate injection period. The control module also controls certain diagnostic functions using the signal from the temperature sensor.

The sensor, which is an NTC resistor, is grounded in the control module and supplied with power (signal) from the control module.

The resistance in the sensor changes according to the temperature of the intake air. This provides the control module with a signal of between 0.5-5 V. The lower the temperature the higher the voltage (high resistance). A high temperature results in low voltage (low resistance).

The engine control module (ECM) can diagnose the temperature sensor. The sensor signal can be read using VIDA (Volvo scan tool).

Scheme 767

The manifold absolute pressure (MAP) sensor is on top of the radiator and is connected to the intake manifold by a hose.

The manifold absolute pressure (MAP) sensor detects quick pressure changes in the intake manifold after the throttle. The signal from the sensor is used by the engine control module (ECM) to supplement the mass air flow (MAF) sensor when calculating injection period.

The semi-conductor sensor is grounded in the control module and is supplied with power from the control module.

The resistance in the intake manifold moves the silicone membrane in the sensor, giving a signal of 0.5 - 4.5 V. Low pressure results in low voltage, high pressure in high voltage.

The engine control module (ECM) can diagnose the manifold absolute pressure (MAP) sensor. The sensor signal can be read using VIDA (Volvo scan tool).

Scheme 768

The function of the leak diagnostic unit is to pressurize the fuel tank system during leak diagnostics.

The leak diagnostic unit consists of a plastic housing with

1. electrical air pump
2. a valve / solenoid which governs the air flow in the unit
3. a heater element (PTC resistor) which warms up the pump.

The electrical pump, valve and heater element in the unit are supplied with voltage by the system relay. The pump, valve and heater element are grounded (control) in the engine control module (ECM).

When leak diagnostics are not active, the valve is held open to ambient air for EVAP control to be carried out.

During leak diagnostics the pump in the leak diagnostic unit starts. The valve in the unit is operated by the engine control module (ECM) by grounding the different circuits internally in the engine control module (ECM).

The Engine control module (ECM) checks the fuel tanks system for leaks by pressurizing the system and at the same time monitoring a number of relevant parameters. Also see: LEAK DIAGNOSTICS (CERTAIN MARKETS ONLY)

The engine control module (ECM) can diagnose the leak diagnostic unit.

The valve in the leak diagnostic unit can be activated.

The leak diagnostic unit is at the upper front edge of the fuel tank.

Scheme 769

The engine speed (RPM) sensor provides the Engine Control Module (ECM) with information about the speed and position of the crankshaft. The Engine Control Module (ECM) is able to use the signal from the engine speed (RPM) sensor to determine when a piston is approaching top dead center (TDC). However it is unable to use the signal from the engine speed (RPM) sensor to determine whether the piston is in the combustion stroke or whether the exhaust valve is open (exhaust stroke). The signal from the camshaft position (CMP) sensor is also required to determine the operating cycle of the engine. See also: CAMSHAFT POSITION (CMP) SENSOR

The signal from the engine speed (RPM) sensor is also used to check the engine for misfires. For more information, see: MISFIRE DIAGNOSTIC

There is a steel ring with stamped holes welded to the rim of the primary section (the section fixed to the crankshaft) of the flywheel.

The holes are positioned with a gap of 6° between each hole. This arrangement creates a hole for each tooth. There are 360° in one revolution. 6° between each hole means that there are 60 holes. However two holes are not stamped, to create a reference position (long gap - missing tooth) for the crankshaft. The first tooth after the reference position is located 84° before TDC on cylinder 1. See: CAMSHAFT CONTROL (CVVT)

The engine speed (RPM) sensor is at the rear of the engine above the flywheel.

The sensor is inductive with a permanent magnet. An alternating current is induced in the sensor when the flywheel/carrier plate passes the engine speed (RPM) sensor. The generated voltage and frequency increases with the engine speed (RPM).

The signal varies between 0.1-100 V depending on the engine speed (RPM).

The Engine Control Module (ECM) is able to determine the engine speed (RPM) by counting the number of holes per time unit. When the reference position passes the engine speed (RPM) sensor, the voltage and frequency drop momentarily to zero, even though the engine is still running. This allows the engine control module (ECM) to determine the position of the crankshaft.

If the signal from the engine speed (RPM) sensor is incorrect or missing, the control module will use signals from the camshaft position (CMP) sensor.

The engine control module (ECM) can diagnose the engine speed (RPM) sensor. The sensor value (engine speed (RPM)) can be read off using VIDA (Volvo scan tool).

Scheme 770

Overview

The fuel pressure sensor is combined and consisted of both the fuel pressure sensor and the fuel temperature sensor. The sensor detects the fuel pressure (the absolute pressure) and the temperature of the fuel in the fuel rail.

The fuel pressure sensor is on the right-hand end of the fuel rail.

Fuel pressure sensor

The pressure sensor is a piezo resistive type resistor, the resistance of which changes with the pressure. Depending on the pressure in the fuel rail, an analog signal of 0-5 V is transmitted. Low pressure results in low voltage, high pressure in high voltage.

The engine control module (ECM) then uses this signal to adjust the pressure in the fuel rail using the fuel pump control module. See also: FUEL PRESSURE REGULATION

The pressure sensor is supplied with 5 V and grounded in the engine control module (ECM). The pressure sensor transmits a signal indicating the fuel pressure to the engine control module (ECM) on a separate cable.

The engine control module (ECM) can diagnose the fuel pressure sensor. Its signals (pressure and temperature) can be read using VIDA (Volvo scan tool).

Note. The absolute pressure is displayed when using VIDA (Volvo scan tool) parameter readout to read off the fuel pressure. If there is no pressure at the fuel rail, the atmospheric pressure will be displayed.

HINT: The relative pressure (absolute pressure minus atmospheric pressure) is displayed when reading off the fuel pressure via a manometer connected to the fuel rail.

Fuel temperature sensor

The temperature sensor is an NTC sensor. The sensor is supplied with voltage (signal) from and grounded in the engine control module (ECM).

The resistance in the sensor changes according to the temperature of the fuel. This provides the engine control module (ECM) with a signal of between 0-5 V. Low temperature results in high voltage (high resistance). High temperature results in low voltage (low resistance).

The engine control module (ECM) uses the signal to calculate the density of the fuel.

Scheme 771

The function of the camshaft position (CMP) sensor is to detect the position of the camshaft rotor flanks. The signal from the sensor is used by the engine control module (ECM) to determine cam timing.

Each camshaft has five flanks per camshaft revolution. Camshaft position sensor (CMP) uses a pulse wheel on the camshaft consisting of five teeth (one tooth positioned by each flank) to detect the flanks.

The flanks are not symmetric on the camshaft. This allows the control module to determine which flank has been detected and therefore which operating cycle the camshaft is in.

When the operating cycle of the camshaft is established, the control module is able to determine which cylinder should be ignited. In the event of misfire or engine knock, the control module is also able to determine which cylinder is misfiring or knocking. See also: KNOCK SENSOR (KS) and ENGINE SPEED (RPM) SENSOR .

Data about the position of the camshaft is used during camshaft control (CVVT). See also: CAMSHAFT CONTROL (CVVT)

The sensor, which is a magnetic resistor with a permanent magnet, is grounded in the control module and supplied with 5 V from the control module. When one of the teeth on the camshaft pulse wheel passes the camshaft position (CMP) sensor, a signal is transmitted to the control module from the camshaft position (CMP) sensor. The signal varies between 0-5 V and is high when a tooth is in contact with the camshaft position (CMP) sensor and low when the tooth leaves the camshaft position (CMP) sensor.

Both the intake camshaft and exhaust camshaft have a camshaft position sensor. Cylinder detection on start up (the operating cycle of each cylinder) is improved by using a camshaft position sensor on the intake camshaft and exhaust camshaft.

The camshaft position (CMP) sensors are located by the camshafts at the rear of the engine.

The engine control module (ECM) can diagnose the camshaft position (CMP) sensors.

Scheme 772

The function of the knock sensor (KS) is to monitor combustion knocking from the engine. Knocking may damage the engine and reduces the efficiency of engine combustion.

If the engine control module (ECM) registers knocking from any of the cylinders, the ignition will be retarded for that cylinder at the next combustion stage. If repeated ignition retardation does not prevent knocking, the injection period will be increased. This has a cooling effect.

The sensor is made up of a Piezo electrical crystal. If there is engine knock, vibrations (sound waves) spread through the cylinder block to the knock sensor (KS). The resulting mechanical stress in the piezo electrical material in the knock sensors generates a voltage. This signal is transmitted to the engine control module (ECM). The signal corresponds to the frequency and amplitude of the sound waves. This allows the Engine Control Module (ECM) to determine if the engine is knocking. The camshaft position (CMP) sensor and engine speed (RPM) sensor are used to determine the operating cycle of the engine (which cylinder is igniting) and therefore which cylinder is knocking.

The knock sensor (KS) is positioned on the cylinder block below the intake manifold.

The engine control module (ECM) can diagnose the knock sensor (KS).

Scheme 773

The electronic throttle unit, using the control signal from the engine control module (ECM), regulates the amount of air for engine combustion. This is done using an electronic shutter.

The electronic throttle unit consists of a round throttle disc on a shaft. This is turned using a DC motor (damper motor), gear wheel and two springs, an opening spring and a return spring. The damper motor is controlled by the control module and is supplied with powered by a built in power stage in the control module. At one of the limit positions the throttle disc is closed so that no air can pass the throttle unit. At the other limit position the throttle disc is parallel to the air flow so that the air is able to freely pass through the throttle unit. The throttle spindle is electronically monitored by two throttle position (TP) sensors (Hall sensors) which are supplied with power by the control module. The signals from the throttle position (TP) sensors provide the control module with data about the position of the throttle disc. The throttle unit also has a connector with six pins.

The electronic throttle unit is located on the engine intake manifold. In the event of a fault, the throttle unit must be replaced as a single unit.

The engine control module (ECM) can diagnose the electronic throttle unit.

THROTTLE POSITION (TP) SENSOR

See: ELECTRONIC THROTTLE UNIT

Scheme 774

The function of the accelerator pedal (AP) position sensor is to provide the engine control module (ECM) and central electronic module (CEM) with information about the position of the accelerator pedal. This data is used by the engine control module (ECM) to deploy the shutter in the throttle unit to the correct angle.

The sensor consists of a plastic housing with circuits. The output signals are a pulse width modulated (PWM) signal and an analog signal related to the accelerator pedal (AP) position.

These signals indicate the position of the accelerator pedal (AP). The pulse width modulation (PWM) signal is transmitted to the engine control module (ECM). The analog signal is transmitted to the central electronic module (CEM) and on to the engine control module (ECM) via the controller area network (CAN).

Normally the pulse width modulation (PWM) signal is used to regulate the throttle angle. In the event of a fault in the pulse width modulation (PWM) signal the analog signal is used as a replacement, unless this is also diagnosed as faulty.

The sensor is supplied with 12 V by the system relay via a fuse and is grounded in the car body.

The pulse width modulation (PWM) signal is also used in conjunction with the analog signal for accelerator pedal (AP) position sensor diagnostics. The accelerator pedal (AP) position sensor signals can be read using VIDA (Volvo scan tool). A diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects a difference between the analog and pulse width modulation (PWM) signals. The engine control module (ECM) then uses the signal with the lowest value for regulation.

The accelerator pedal (AP) position sensor is located on the accelerator pedal bracket.

Scheme 775

Engine control module (ECM) receives information about the clutch pedal's position in two ways.

Partly from a clutch pedal position sensor which is directly connected to Central electronic module (CEM), and partly from a clutch pedal switch directly connected to the Engine control module (ECM).

The function of the clutch pedal switch is to provide extra safety for the function autostart. In order for the function to be activated, the Engine control module (ECM) must receive signal that indicates pressed down pedal from the clutch pedal switch.

To start without the function autostart it is enough that any of the signals (from clutch pedal position sensor or clutch pedal switch) indicates pressed down pedal.

In its starting position, the clutch pedal switch is open (clutch pedal released). The switch's installation shall be adjusted so that is closed when the clutch pedal passes 75% of full pedal movement.

The clutch pedal switch is on the pedal box by the clutch pedal.

The engine control module (ECM) can diagnose the clutch pedal switch. The status (position) of the switch can be read using the diagnostic tool.

Note. Read-out only works on vehicles built after week 46 2007.

Scheme 776

The function of the main relay (system relay) is to supply certain components with voltage.

The relay is mechanical and has a closing and opening function. In the rest position the circuit in the relay is open.

The main relay terminals (#30 and #86) are supplied with voltage by the battery. When the ignition key has been turned and the engine control module (ECM) is powered, the terminal (#85) on the main relay is grounded by the engine control module (ECM).

When the terminal (#85) is grounded, the relay is activated and a number of components are powered via the relay terminal (#87).

The main relay is in the integrated relay/fuse box in the engine compartment and is diagnosed by the engine control module (ECM).

Scheme 777

The air conditioning (A/C) relay supplies the A/C compressor with voltage. The relay is controlled by the engine control module (ECM) based on information from different signals

1. the climate control module (CCM) (via the control area network (CAN))
2. the engine coolant temperature
3. the position of the accelerator pedal (AP)
4. the pressure in the system.

The engine control module (ECM) can temporarily disengage the A/C compressor during wide open throttle (WOT) acceleration.

The relay is mechanical. It has a closing / breaking function and is supplied with power from the system relay.

In the rest position the circuit in the relay is open.

The system relay supplies the coil and the relay with power. The relay activates when the coil is grounded in the engine control module (ECM), the circuit closes and the A/C compressor is supplied with power via the relay voltage output.

The relay coil is grounded (signal) when the engine control module (ECM) receives a signal via the Controller area network (CAN) from the climate control module (CCM) to activate the relay and start the compressor.

FUEL PUMP (FP) RELAY

See central electronic module (CEM).

STARTER MOTOR RELAY

The function of the starter motor relay is to supply power to the starter motor. See also: START

The starter motor relay is in the relay/fuse box in the engine compartment.

Scheme 778

The function of the injectors is to spray fuel into the cylinders in the correct spray patterns. This happens sequentially.

The injectors are in the intake manifold.

It is essential that the injectors are correctly installed with no air leakage around them. Fuel leakage from the top of an injector when it is not activated may lead to starting and driving problems.

The engine control module (ECM) controls the injectors by grounding the valves in pulses.

The engine control module (ECM) can diagnose the injectors. The injectors can be activated using VIDA (Volvo scan tool).

Scheme 779

The evaporative emission system (EVAP) valve is used to open and close the connection between the EVAP canister and the intake manifold. The valve controls the flow of hydro-carbons (fuel vapor) from the EVAP canister to the engine intake manifold using the vacuum in the intake manifold. This ensures that hydro-carbons stored in the EVAP canister are used in the engine combustion process.

The valve is an electro-magnetic valve which is powered from the system relay. When the valve needs to be opened, it is grounded internally in the engine control module (ECM). The evaporative emission system (EVAP) valve is closed when in the standby position (open-circuit).

When the control module requests that the EVAP canister should be drained (the hydrocarbons stored in the canister should be released into the engine), the control module deploys the evaporative emission system (EVAP) valve by grounding it. A pulse width modulation (PWM) signal is used to ground the valve and to control the degree to which the valve will open. In this way, the drainage of the EVAP canister is matched to the volumetric efficiency of the EVAP canister, the engine speed (RPM) and the engine load.

The engine control module (ECM) can diagnose the evaporative emission system (EVAP) valve. The valve can be activated using VIDA (Volvo scan tool).

The evaporative emission system (EVAP) valve is close to the intake manifold.

Scheme 780

The camshaft reset valve controls the oil flow to the CVVT unit (camshaft pulley).

The valve consists of an electro-magnetic valve with a spring-loaded piston. There are slits in the piston which channel the engine lubricating oil to the CVVT unit by moving the piston in the reset valve. The continuous variable valve timing (CVVT) unit turns the camshaft (the camshaft timing changes). The direction in which the camshaft turns depends on the chamber in the CVVT unit which is supplied with oil (pressure). See also: CAMSHAFT CONTROL (CVVT)

The system relay supplies the reset valve with voltage. The valve is grounded (control stage) in the engine control module (ECM). When the valve is grounded using a pulse width modulation (PWM) signal, the oil flow in the valve can be regulated to the different chambers in the continuous variable valve timing (CVVT) unit at variable rates. This allow the angle of the camshaft to be changed precisely and smoothly.

The engine control module (ECM) can diagnose the camshaft reset valve.

The valve is located on the cylinder head above the intake camshaft.

Scheme 781

The ignition coils supply the spark plugs with high voltage to produce sparks. The engine control module (ECM) controls the ignition coils so that sparks are generated at the correct time.

Each ignition coil has its own integrated power stage.

The ignition coils are in the sparkplug wells above each spark plug.

The engine control module (ECM) can diagnose the ignition coils.

Scheme 782

The emissions warning lamp in the Driver Information Module (DIM) has a warning symbol. This warning symbol varies depending on the market. The warning symbols are

1. Engine symbol" (not USA)
2. CHECK ENGINE" (MIL - Malfunction Indicator Lamp, USA only).

The warning lamp lights when the ignition key is turned to position II. The warning lamp will go out after approximately 15 seconds or if the engine is started when no fault is found in the engine management system.

The warning lamp will light if there is a fault in one of the parameters in the engine management system. The warning lamp will also light in response to a request transmitted via the control area network (CAN) if there is a fault in the transmission control module (TCM) which affects emissions.

SUBSTITUTE VALUE

For certain types of diagnostic trouble codes (DTCs), the missing signal is replaced with a substitute value so that the system can continue functioning.

LIGHTING THE MALFUNCTION INDICATOR LAMP (MIL)

In the event of emissions related diagnostic trouble codes (DTCs), a counter counts down to determine when to light the malfunction indicator lamp (MIL). The conditions for lighting the malfunction indicator lamp (MIL) vary depending on which diagnostic trouble code (DTC) is stored.

Scheme 783

All gases that evaporate from fuel in the fuel tank must be led to and stored in the evaporative emission system (EVAP) canister so that they can be directed into the engine for combustion. In order to detect leakages which cause evaporation of gases into the air, the fuel tank system is diagnosed for leakage. The fuel tank system consists of

1. fuel tank
2. the EVAP canister purge valve (1)
3. EVAP canister (2)
4. leak diagnostic unit (3)
5. air cleaner (ACL) (4)
6. Roll-over valve (5)
7. Float Limit Vent Valve (6)
8. fuel filler pipe (7)
9. all lines between the above components.

The fuel tank system has a leak diagnostic unit to diagnose any leakage. The leak diagnostic unit pressurizes the fuel tank system when the ignition is off, if the conditions for diagnosis have been met. The control module can detect faults in the function of the leak diagnostic unit and leakage that is 0.5 mm or greater. Minor leak; leakage greater than 0.5 mm but less than 1.0 mm. Major leak (fuel tank filler cap missing for example) leakage greater than 1.0 mm.

The leak diagnostic unit consists of a pump and a valve that controls the air flow in the unit. The fuel tank system tests for leaks by measuring the power consumption of the pump. The power consumption of the pump corresponds to a certain pressure in the fuel tank system. During diagnosis, the rate at which the pressure can build up is checked, taking into account the quantity of fuel in the tank. The quicker the pressurization the better the fuel tank system is sealed.

Conditions for diagnosis

The diagnosis begins when all the following conditions are met

1. There must be no diagnostic trouble code (DTC) stored for the following components or functions: the power stage for the pump in the leak diagnostic unit the power stage for the valve in the leak diagnostic unit the power stage for the EVAP canister purge valve the EVAP canister purge valve.
2. Engine off for at least 5 hours (context), engine running for at least 20 minutes (context).
3. Ignition off
4. Vehicle speed 0 km/h.
5. Engine coolant temperature (ECT) +4 °C or higher
6. Maximum altitude of 2500 meters above sea level
7. Outside temperature between +4 and +35 °C
8. Stable signal from the fuel level sensor
9. Fuel volume in the tank between 15-85 %
10. Battery voltage between 11.0-14.5 V. The voltage must be stable.
11. EVAP canister purge valve closed
12. Low volume in the canister.

Diagnostic phases

The diagnostic is divided into the following phases and is carried out in sequence when all conditions for the diagnostic have been met.

1. reference phase 1
2. function test
3. leak diagnostic
4. reference phase 2 (only during minor leak diagnostics, if the previous phase detected leaks).

Scheme 784

Reference phase 1 (1-2)

The illustration is a diagram of a fault free fuel tank system.

Before the leak diagnostic begins, the control module runs reference phase 1 for leakage. During reference phase 1 ( 1-2 ) for leakage that is 0.5 mm, the pump in the leak diagnostic unit pumps ambient air through a 0.5 mm hole and back out to the ambient air. At the same time, the power consumption ( A ) of the pump is measured and stored in the control module. The stored value ( A ) for the power consumption of the pump corresponds to a leakage of 0.5 mm. This value is then used by the engine control module (ECM) to determine the leak status of the fuel tank system.

Function test (1-3)

If the value for the power consumption of the pump is too high or low during reference phase 1 ( 1-2 ), or if the value for pump power consumption varies too much during reference phase 1 ( 1-2 ), the diagnostic is cancelled and starts again the next time the conditions for the diagnostic are met. A diagnostic trouble code (DTC) is stored if the diagnostic is cancelled because the power consumption of the pump is varying excessively.

After reference phase 1, the valve ( 2 ) in the leak diagnostic unit is activated and controls the air flow to the fuel tank to pressurize the fuel tank system. This change of air flow will cause the power consumption of the pump to fall briefly before the pressure builds up in the fuel tank system ( in the illustration). A diagnostic trouble code is stored if the value for the power consumption of the pump drops too quickly, slowly or not at all.

Scheme 785

Leak diagnostic, major leak (leakage greater than 1.0 mm)

The diagnostic for "major leaks" is carried out every other time when the conditions for the diagnostic are met. The leak diagnostic unit pressurizes the fuel tank system, measures the power consumption of the pump ( 4 ) and compares this with a calculated desired value ( B ). If the measured value reaches the calculated desired value within a certain time frame (determined by the fuel level in the tank), the engine control module (ECM) assumes that the fuel tank system is free of major leaks.

If a diagnostic trouble code (DTC) for major leaks is stored by the engine control module (ECM), a diagnostic trouble code (DTC) for fuel tank filler cap missing will also be stored and the driver will be notified by a text message in the driver information module (DIM).

Leak diagnostic, minor leak (leakage greater than 0.5 mm but less than 1.0 mm)

The diagnostic for minor leaks is run every 14th time the conditions for the diagnostic are met. The diagnostic for major leaks is always run before the diagnostic for minor leaks. The leak diagnostic unit continues to pressurize the fuel tank system ( 5 ). If the measured value ( 6 ) is the same or less than the value stored in reference phase 1 ( A ) (minor leak) after a certain amount of time (the time is determined by the fuel level in the tank), reference phase 2 is run (see " Reference phase 2 " below).

A diagnostic trouble code (DTC) for minor leakage is stored, depending on the power consumption of the pump during reference phase 2.

Scheme 786

Reference phase 2

The illustration shows the reference phase after the diagnostic for minor leaks, sealed fuel tank system.

Reference phase 2 is run when the power consumption of the pump is too low during the diagnostic for leakage. This is to ensure that lower power consumption during the minor leak diagnostic ( 6 ) is not caused by changes in components. If the measured power consumption during reference phase 2 ( 7 ) is lower than that measured during pressurization ( 6 ), the control module interprets this as meaning that the fuel tank system is sealed. A diagnostic trouble code (DTC) for minor leakage is stored if the measured power consumption from reference phase 2 ( 7 ) is the same or higher than that measured during pressurization ( 6 ).

When replacing the engine control module (ECM), the hardware number on the control module is read and transmitted to the Volvo central database. The software is compiled depending on the configuration of the vehicle (for example, structure week and hardware number). The software is then transmitted to VIDA (Volvo scan tool) and downloading is carried out.

A vehicle identity check, a read off of the vehicle's new configuration for updating the Volvo central database and programming of codes are included in the download sequence. The procedure when updating software is identical except that the hardware number is not read but taken directly from the Volvo central database.

The engine control module (ECM) is included in the immobilizer system and a number of conditions must be met for the control module to approve a start.

Immobilizer code: During a start attempt, the central electronic module (CEM) transmits its immobilizer code and the engine control module (ECM) compares this with its own programmed code. This condition is met if the codes correspond.

Serial number: The serial number for the brake control module (BCM) is programmed into the engine control module (ECM). During a start attempt the engine control module (ECM) transmits a query to the brake control module (BCM) about which serial number it has programmed in and then compares this with the serial number programmed into the engine control module (ECM). This condition is met if the serial numbers correspond.

Both conditions must be met to allow a start. When replacing the engine control module (ECM), both the immobilizer code and serial number are programmed automatically when downloading software.

Scheme 787

The starter motor (6/25) is powered via the starter motor relay (2/35). The relay is controlled by the engine control module (ECM) (4/46). The start process is as follows

1. The ignition key is turned to start position (position III)
2. A high signal from the ignition switch (3/1) is transmitted to the engine control module (ECM) via the central electronic module (CEM) and integrated relay/fusebox in the engine compartment. The engine control module (ECM) interprets this high signal as a request to activate the starter motor.
3. The engine control module (ECM) activates the starter motor by grounding the relay for the starter motor relay. The relay is powered by the ignition switch
4. The relay closes the circuit between the starter motor solenoid and the battery, activating the starter motor
5. The engine control module (ECM) activates the starter motor until the ignition key is released from the start position (position III).

The starter motor will not be activated if

1. the function for electronic Immobilizer does not allow start. The engine control module (ECM) receives signal regarding if the electronic immobilizer is active or inactive, from the central electronic module (CEM) via the CAN-net.
2. the gear selector is not in position "P" or "N" (automatic transmissions). The engine control module (ECM) receives a signal indicating the position of the gear selector from the transmission control module (TCM) (4/28) via both the controller area network (CAN) and from a directly connected cable between the engine control module (ECM) and transmission control module (TCM).
3. the clutch pedal is released (manual transmissions, certain markets). The engine control module (ECM) receives a signal indicating the position of the clutch pedal from the central electronic module (CEM) via the controller area network (CAN).

Auto start (2007-)

If the ignition key is released from position III before the engine is started, the starter motor continues to run. The starter motor runs until the engine is started or until after a certain amount of time. The engine coolant temperature (ECT) determines how long the starter motor is permitted to run

1. at -40 °C, approx. 10 seconds
2. at -10 °C, approx. 8 seconds
3. over 15 °C, approx. 4 seconds.

If the engine does not turn or if the engine speed is extremely low when the start relay is activated, the engine control module (ECM) interrupts start relay activation.

Activation of the starter motor is not permitted or is interrupted if

1. the engine is running (the engine speed (RPM) above a certain value)
2. the immobilizer function does not allow a start
3. the gear selector is not in position "P" or "N" (automatic transmissions). The engine control module (ECM) receives a signal indicating the position of the gear selector from the transmission control module (TCM) (4/28) via both the controller area network (CAN) and from a directly connected cable between the engine control module (ECM) and transmission control module (TCM).
4. the clutch pedal is not depressed (manual transmission). The signal about the clutch pedal position (clutch pedal sensor) is received by the engine control module (ECM) (4/56), via the controller area network (CAN) and via a directly connected cable from the clutch pedal switch (3/271).
5. the brake pedal is not depressed (automatic transmission).

Scheme 788

When the camshaft (A) is set at the factory, it is aligned with the position of the crankshaft (B). The position of the camshaft in relation to the crankshaft is designated the camshaft 0 position . During camshaft (CVVT) control, the 0 position of the camshaft is advanced so that the opening and closing of the intake valves can be changed to relative to the camshaft. By controlling the camshaft (the camshaft is regulated from its 0 position) the performance of the engine is increased, the idle speed quality is improved and the emissions are reduced.

There are diagnostics for this function. See also: CAMSHAFT DIAGNOSTICS (CVVT)

Camshaft position detection

Scheme 789

In order to detect the position of the camshaft in relation to the crankshaft, the engine control module (ECM) uses the signals from the engine speed (RPM) sensor (the position of the crankshaft) and from the camshaft position (CMP) sensor (the position of the camshaft). The control module uses these two signals to determine the position of the camshaft in relation to the position of the crankshaft.

Both the intake camshaft and exhaust camshaft have a camshaft position sensor. Cylinder detection on start up (the operating cycle of each cylinder) is improved by using a camshaft position sensor on the intake camshaft and exhaust camshaft.

The following description applies to the intake camshaft.

Scheme 790

Detecting the camshaft flanks

The camshaft is divided into five flanks per camshaft revolution (flanks 1-5). The flanks are detected by the camshaft position (CMP) sensor. Its signal is affected by the shape of the camshaft rotor. See also: CAMSHAFT POSITION (CMP) SENSOR

Because the teeth on the camshaft pulse wheel are differently designed the control module can determine the position of the camshaft using the camshaft position (CMP) sensor signal. The control module is able to establish which combustion cycle the cylinders are in.

Scheme 791

Detecting the reference positions of the camshaft

The crankshaft has five reference positions, one for each camshaft flank. The reference positions are predetermined points on the flywheel. The reference positions are detected using the signal from the engine speed (RPM) sensor. See also: ENGINE SPEED (RPM) SENSOR

The camshaft rotates at half the speed of the crankshaft. Two engine revolutions are required to detect all five camshaft flanks

The positions on the flywheel are designated °CA (Crank angle). 0°CA = Top dead center cylinder 1.

Scheme 792

Detecting the position of the camshaft in relation to the position of the crankshaft

Each camshaft flank aligns with pre-defined positions on the crankshaft when the camshaft is in its 0 position. These positions on the crankshaft are called flank reference positions. Each flank is 33°CA before top dead center (BTDC) when the camshaft is in its 0 position (camshaft not deployed), see D1-D5 in illustration.

A: Engine speed (RPM) sensor signal.

B: Camshaft position (CMP) sensor signal, intake. From high to low signal when the teeth on the camshaft pulley leave the camshaft position (CMP) sensor.

C: Low engine speed (RPM) sensor signal because of the holes in the flywheel/carrier plate.

1: Top dead center (TDC) cylinder 1, 0°CA (84°CA after hole " C " in the flywheel/carrier plate).

2: Top dead center (TDC) cylinder 2, 144°CA.

4: Top dead center (TDC) cylinder 4, 288°CA.

5: Top dead center (TDC) cylinder 5, 432°CA.

3: Top dead center (TDC) cylinder 3, 576°CA.

Regulating the camshaft position

To control the intake camshaft the engine control module (ECM) regulates the infinitely variable camshaft reset valve. The valve controls the flow of engine oil to the continuous variable valve timing (CVVT) unit which is affected by the oil pressure that builds up. This allows the CVVT unit to change the position of the camshaft. Also, see " Control, CVVT unit " below and CAMSHAFT RESET VALVE (CONTINUOUS VARIABLE VALVE TIMING (CVVT))

When controlling the camshaft position (the engine control module (ECM) controls the camshaft), detection of the camshaft flanks will be offset from the reference positions on the crankshaft. Angles D1-D5 shown in the illustration will increase when the camshaft is controlled.

HINT: The exhaust camshaft signals are the same as those of the intake camshaft. However, the exhaust camshaft flanks are 318°CA before the intake camshaft flanks.

The engine control module (ECM) is then able to calculate the °CA (crankshaft degrees from top dead center (TDC)) that the intake valve opens and the exhaust valve closes for each cylinder. This is because the opening and closing angles are fixed and predefined in relation to the camshaft flanks.

The camshaft position relative to the crankshaft position can be read in VIDA (Volvo scan tool).

Control, CVVT unit

Scheme 793

HINT: The illustration is a view of the CVVT unit from the side and from the rear.

1: Timing belt pulley

2: Lock pin with spring

3: Rotor

4: Rotor wings

A1: Chamber A

B1: Chamber B

The continuous variable valve timing (CVVT) unit allows the position of the camshaft to be adjusted relative to the crankshaft.

The camshaft is secured to the rotor (3). The rotor (and with it the camshaft) rotates in relation to the timing belt pulley (1) within set angles.

When the camshaft is in its 0 position, the timing belt pulley and the rotor are locked together by the lock pin (2). A spring-loaded lock pin slides into a hole on the inside of the end of the timing belt pulley to secure it.

Camshaft reset valve

Scheme 794

5: Piston with slits

6: Return spring

A: Channel leading to chamber A1 in the CVVT unit

B: Channel leading to chamber B1 in the CVVT unit

C: Channel for oil (pressure)

D: Channel for oil (return)

The camshaft reset valve controls the oil flow to the continuous variable valve timing (CVVT) unit. The engine control module (ECM) uses a pulse width modulation (PWM) signal to control the valve. See also: CAMSHAFT RESET VALVE (CONTINUOUS VARIABLE VALVE TIMING (CVVT))

Control takes place as follows when deploying the camshaft

Scheme 795

HINT: The illustration is a view of the CVVT unit from the side and from the rear.

1. The oil is forced from the engine lubrication system (C)
2. The valve is grounded by the engine control module (ECM). The oil flows via the slits in the piston (5) to the oil channel (A) in the camshaft
3. The oil flows via oil channels in the camshaft to the top of the lock pin (2). If the camshaft is in its 0 position, the lock pin will be forced in by the oil pressure and the rotor releases from the timing belt pulley
4. The chamber (A1) fills with oil. The oil pressure will rotate the rotor (3)
5. The oil in the chamber (B1) will be forced out of the chamber by the rotation of the rotor. The oil flows to the engine oil pan via the camshaft, channel (D) and the valve.

Control takes place as follows when returning the camshaft

Scheme 796

HINT: The illustration is a view of the CVVT unit from the side and from the rear.

1. The oil is forced from the engine lubrication system (C)
2. The engine control module (ECM) breaks the ground connection for the valve. The piston (5) in the valve springs back (6) and the oil flows via the piston slits in the valve to the oil channel (B) in the camshaft
3. The chamber (B1) fills with oil. The oil pressure in the chamber will rotate the rotor
4. The rotor (4) reaches its limit position and the lock pin slides into a hole on the inside of the front end of the camshaft pulley
5. The oil in the chamber (A1) will be forced out of the chamber by the rotation of the rotor. The oil flows to the engine oil pan via the camshaft, channel (D) and the valve.

The reset valve is controlled by the engine control module (ECM) at high frequency. The frequency changes for deployment and return. This ensures rapid and precise control. The extent of camshaft control (change in the camshaft radial position) varies depending on the engine variant.

Scheme 797

Fuel pressure regulation for demand controlled fuel pumps (DECOS - Demand Controlled fuel Supply) means that the fuel pressure is controlled steplessly by varying the output of the fuel pump. The design of the system allows a greater maximum pressure (approximately 6.5 bar) in the fuel pump. This pressure is used in extreme situations, such as heavy engine load for example.

The following components are used for fuel pressure regulation

1. engine control module (ECM) (4/46)
2. fuel pump control module (4/83)
3. fuel pressure sensor with fuel temperature sensor (7/156)
4. fuel pump with by-pass valve (6/33).

The time taken for the engine start procedure can be reduced by rapidly increasing the pressure in the fuel rail when the engine control module (ECM) receives a signal about the position of the ignition switch from the central electronic module (CEM).

The engine control module (ECM) is better able to calculate the injection period because the signal from the fuel pressure sensor provides information about the fuel pressure and actual fuel temperature. This particular improves the cold starting characteristics of the engine.

The advantages of varying the output of the fuel pump so that it is not always at full power are

1. the total power consumption of the fuel pump (FP) is reduced, reducing the load on the power supply system
2. the service life of the fuel pump (FP) is increased
3. fuel pump noise is reduced.

Control

The engine control module (ECM) attempts to maintain a fuel pressure of 480 kPa (absolute pressure). A pulse width modulation (PWM) signal from the engine control module (ECM) to the fuel pump (FP) control module requests an increase or decrease in pressure. The fuel pump control module then operates the fuel pump unit to obtain the desired pressure using a pulse width modulation voltage on the ground lead. The fuel pump (FP) can be controlled steplessly by changing the pulse width modulation (PWM) signal. Only that pressure which is required at that specific time will then be released to the fuel rail/injectors. The value of the pulse width modulation (PWM) signal is a measurement of the operational load of the fuel pump (FP) (% duty, 100% = maximum pressure).

The engine control module (ECM) continuously monitors the fuel pressure using the signal from the fuel pressure sensor. This allows the desired fuel pressure to be achieved. If necessary, the signal to the fuel pump control module can be changed so that it corresponds to that required to achieve the requested fuel pressure.

By-pass valve

When the injectors are closed because of too high pressure (during engine braking for example) there is a pressure peak. The by-pass valve in the fuel pump (FP) is used to even out the pressure peak. The opening pressure of the valve is approximately 6.5 bar.

The by-pass valve also functions as a non-return valve, ensuring that the fuel pressure in the system is maintained when the engine is switched off.

There is high pressure before the engine is started. This high pressure means that the valve in the by-pass valve opens and the system is "flushed".

Passive safety

For safety reasons, the engine control module (ECM) shuts off the fuel pump (FP) if the supplemental restraint system module (SRS) detects a collision.

Scheme 798

To ensure that the correct throttle angle is reached, the engine control module (ECM) controls the throttle shutter in the throttle unit (6/120), mainly using the signal from

1. accelerator pedal (AP) position sensor (7/51)
2. clutch pedal sensor (7/123) via central electronic module (CEM) (4/56)
3. stop lamp switch (3/9)
4. the throttle position (TP) sensor on the electronic throttle unit (6/120)
5. brake pedal sensor (7/124) via brake control module (BCM) (4/16).

Additional signals and parameters are used to ensure optimum throttle control. By example by compensating for

1. the load from the air conditioning (A/C) compressor
2. the load from the transmission depending on the selected gear mode (automatic)
3. engine coolant temperature (ECT).

In a combustion engine, the difference between the minimum and maximum airflow is considerable. The smaller air flows need more thorough regulation (for example during idle air trim), so the throttle position (TP) sensor signal 1 is amplified approximately 4 times in the engine control module (ECM) before it reaches the Analog/Digital converter in the engine control module (ECM). This means that there are three, two real and one fictitious, input signals available to the engine control module (ECM). These signals are used to determine the position of the throttle disc and to control the throttle motor to the correct throttle angle.

Because the signal is amplified, it reaches its maximum value at approximately a quarter of maximum deployment.

The engine control module (ECM) primarily uses the signal from throttle position (TP) sensor 1 as a measurement of throttle opening. The signal from throttle position (TP) sensor 2 is mainly to check that throttle position (TP) sensor 1 is working. The engine control module (ECM) then uses the signal to calculate a throttle angle (actual value). This is the actual throttle angle. The value for the actual throttle angle is used by those functions in the engine control module (ECM) which depend on this information so that the throttle can be correctly regulated.

There is an adaptation (learning) in the engine control module (ECM) so that the control module can calculate how the damper motor needs to be controlled. See " Adaptation of the electronic throttle unit " below. This adaptation occurs automatically when necessary. The engine control module (ECM) moves the throttle disc to the different positions and reads off and registers the actual values from the throttle position (TP) sensors.

The throttle angle is regulated so that the actual angle (actual value) is the same as the angle calculated by the engine control module (ECM) (desired value). The engine control module (ECM) also uses the values that were stored during adaptation of the throttle angle, and the actual signals from the throttle position (TP) sensor.

The damper motor is deployed by the integrated power stage in the engine control module (ECM) using a pulse width modulation (PWM) signal. The torsion from the opening and return springs in the electronic throttle unit is also used. If the engine control module (ECM) detects a fault in the electronic throttle unit so that the throttle disc cannot be controlled, the springs in the throttle unit will turn the throttle disc to the limp home position (return position). This return position is calibrated to provide a throttle angle large enough to allow the car to be driven to a workshop, although with considerably reduced driveability.

Throttle angle

The engine control module (ECM) also monitors the throttle unit signals from the throttle position (TP) sensors, to ensure that these signals are within the parameters and correspond to the same throttle angle.

If the difference between the signals exceeds a set limit the maximum value is selected as the actual value (which means that the throttle disc is controlled down). If the engine control module (ECM) detects a fault in both throttle position sensors, the electronic throttle unit power stage is switched off. The throttle switches to limp home mode (return position). Diagnostic trouble codes (DTC) are stored in the engine control module (ECM) if faults are detected in the throttle position (TP) sensors.

Adaptation of the electronic throttle unit

Adaptation of the electronic throttle unit is carried out automatically when requested by the engine control module (ECM). Adaptation is carried out to check the function of the electronic throttle unit, and, if necessary, to update the values obtained from the throttle position (TP) sensors etc. during regulation, as these values can change somewhat over the service life of the throttle unit. Diagnostic trouble codes (DTC) are stored in the engine control module (ECM) if faults are detected in the electronic throttle unit.

Scheme 799

Overview

Fuel trim reduces exhaust emissions. Fuel trim reduces nitrous oxides (NO x ), carbon monoxide (CO) and hydrocarbon (HC) emissions.

Theoretically, if the correct amount of oxygen is added during combustion, fuel can be converted to water (H 2 O) and carbon dioxide (CO 2 ). Emissions would then be completely safe.

In practice considerable amounts of hydro-carbons (HC) and varying amounts of carbon monoxide (CO) and carbon dioxide (CO 2 ) remain.

Scheme 800

Due to the high temperature and pressure, nitrous oxides such as NO and NO 2 are also formed. The common designation for these gases is nitrous oxides NO x .

Scheme 801

By speeding up the reaction between the remaining reactive components using a catalytic converter, these can be converted to water (H 2 O), carbon dioxide (CO 2 ) and nitrogen (N 2 ).

However this can only happen if the balance of hydro-carbons (HC), carbon monoxide (CO), oxygen (O 2 ) and nitrous oxides (NO x ) is exactly right in the exhaust. This happens when the fuel air mixture before combustion is 14.7 kg of air per kg of fuel. The Lambda value is then said to be one, (lambda=1).

Scheme 802

A base program in the engine control module (ECM) calculates the injection period based on data about load, i. e. the measured air mass and engine speed (RPM). The calculated injection time (from the base program) is then modified by a circuit (short-term fuel trim). The signal from the heated oxygen sensor (HO2S) is used to finely adjust the injection period so that lambda=1 is reached. The short-term fuel trim is also a circuit that finely adjusts the injection period so that the fuel air mixture is optimized (lambda=1). The control module also used the signals from the front and rear heated oxygen sensors (HO2S) to correct the front heated oxygen sensor (HO2S) (offset adjustment) and thereby the injection period. This gives a higher degree of accuracy during fuel trim. Fuel trim is a rapid process which may take place several times a second. Adjustment of the calculated injection period calculated in the base program is limited.

The integrator can be read using VIDA (Volvo scan tool).

Adaptive functions

Scheme 803

Certain factors, such as deviations in tolerance for certain components such as the mass air flow (MAF) sensor and injectors, intake air leakage, fuel pressure etc, will affect the composition of the fuel air mixture. To compensate for this, the engine control module (ECM) has adaptive (self learning) functions. When the engine is new, the short-term fuel trim is assumed to vary cyclically around a nominal center line (A) 1.00 with, for example, a ± 5% change in the injection period when fuel trim is active.

If there is air leakage the short-term fuel trim will be offset to a new position (B) and will then work for example between 1.10 (+10%) and 1.20 (+20%), although still at an amplitude of 5%, but with an offset in relation to the original center line (A). The injection period has then been increased to compensate the increase in the amount of air.

The adaptive functions will correct the change, so that the short-term fuel trim will work around the new center line (B) where it will again have its full range of control available.

Put simply, fuel trim is a measurement of the difference (C) between the original short-term fuel trim center line (A) and the new center line (B).

Scheme 804

The adaptive functions consist of two sections and correspond to the different operating ranges of the engine, load (D) and engine speed (E)

1. Additive adaptation (1) is when the engine is idling. This is how the control module adjusts the CO content at idle speed. Long-term fuel trim, idling can be read off using VIDA (Volvo scan tool).
2. Multiplicative adaptation (2), carried out at loads and engine speeds above idle. Long-term fuel trim, load can be read off using VIDA (Volvo scan tool).

The adaptive adjustments of the injection period are stored continuously in the control module. This means that under different operating conditions the fuel air mixture is obtained before the heated oxygen sensor (HO2S) is warm enough to function.

A diagnostic trouble code (DTC) will be stored in the control module if any adaptation value is too high or too low. For further information, also see: HEATED OXYGEN SENSOR (HO2S) DIAGNOSTIC

Scheme 805

Knock occurs in the combustion chamber when the fuel and air mixture self ignites. This can occur either before or after the spark plug has produced an ignition spark. In both cases the gas in two or more places ignites in the combustion chamber.

This results in an extremely fast combustion process with flames from several directions. When these flames collide, the pressure in the cylinder increases rapidly and there is a mechanical knocking sound.

If any of the cylinders knock there is a specific type of vibration in the cylinder block. These vibrations are transferred to the knock sensor (KS) which is screwed into place in the cylinder block. The resulting mechanical stress in the piezo electrical material in the knock sensors generates a voltage. The engine control module (ECM) can then determine which cylinder is knocking with the help of the camshaft position (CMP) sensor and the engine speed (RPM) sensor.

The knock sensor (KS) also senses some normal engine sound. The control module is able to recognize the vibrations which correspond to knocking by filtering, amplifying and using software to evaluate the signal.

If the knock sensor (KS) detects knocking in the engine above a certain threshold value, the ignition timing is first retarded and then the fuel/air mixture is enriched to eliminate knocking.

Scheme 806

The following components are used for ignition control

1. engine speed (RPM) sensor (7/25)
2. camshaft position (CMP) sensor (7/172-7/173)
3. mass air flow (MAF) sensor (7/17)
4. engine coolant temperature (ECT) sensor (7/16)
5. throttle position (TP) sensor on the electronic throttle unit (6/120)
6. knock sensor (KS) (7/24)
7. transmission control module (TCM) (4/28)
8. spark plugs with ignition coils (20/3-20/7)
9. brake control module (BCM) (4/16).

The engine control module (ECM) calculates the optimum ignition advance based on the software and information from the sensors. The engine control module (ECM) cuts the current to the ignition coil mounted on the cylinder to be ignited and produces a spark.

During the starting phase the engine control module (ECM) produces a fixed ignition setting. When the engine has started and the vehicle is being driven, the engine control module (ECM) calculates the optimum ignition setting, taking factors such as the following into account

1. engine speed (RPM)
2. load
3. temperature.

The engine control module (ECM) analyses the signal from the knock sensor (KS) when the engine reaches operating temperature. If any of the cylinders knock, the ignition is retarded for that specific cylinder until the knocking ceases.

The ignition then advanced to the normal position or until the knock recurs.

Before the transmission control module (TCM) changes gear, it sometimes transmits a torque limiting request to the engine control module (ECM). The engine control module (ECM) then retards the ignition momentarily to reduce the torque, resulting in smoother gear changes and reducing the load on the transmission. There are different ignition retardation levels depending on the signals from the transmission control module (TCM). The return signal from the engine control module (ECM) to the transmission control module (TCM) confirms that the signal reached the engine control module (ECM). The Brake Control Module (BCM) transmits information to the engine control module (ECM) about deviations in the drive line. The signal is used to stop the diagnosis. For further information, also see: MISFIRE DIAGNOSTIC

The engine misfires if the fuel does not ignite correctly. For further information, also see: MISFIRE DIAGNOSTIC

Scheme 807

The air conditioning (A/C) compressor is controlled by the engine control module (ECM) (4/46) on request from the climate control module (CCM) (3/112) via the controller area network (CAN). When the engine control module (ECM) receives a signal from the climate control module (CCM) to activate the air conditioning (A/C) compressor, the engine control module (ECM) grounds the circuit for the relay coil for the A/C compressor. See also: AIR CONDITIONING (A/C) RELAY

The relay (2/22) closes the circuit between the integrated relay/fuse box in the engine compartment and the clutch for the A/C compressor (8/3).

In addition to the information from the climate control module (CCM), the engine control module (ECM) checks the engagement and disengagement of the A/C compressor based on

1. the signal from the air conditioning (A/C) pressure sensor (high pressure side) (7/8)
2. the signal from the air conditioning (A/C) pressure sensor (low pressure side) (8/119)
3. the throttle position (TP) sensor (6/120)
4. the engine coolant temperature (ECT) sensor (7/16).

Scheme 808

The cruise control function is an example of distributed functionality.

The following components are used when regulating the cruise control

1. engine control module (ECM) (4/46)
2. steering wheel module (SWM) (3/254) (cruise control buttons)
3. central electronic module (CEM) (4/56) (clutch pedal position)
4. brake control module (BCM) (4/16) (brake pedal position, speed signal)
5. driver information module (DIM) (5/1) (cruise control lamp)
6. transmission control module (TCM) (4/28) (cruise control active/not active, gear selector in position "P" or "N")
7. electronic throttle unit (6/120)
8. stop lamp switch (3/9)

To activate cruise control the function must be switched on using the "CRUISE" button. A lamp lights up in the driver information module (DIM).

The driver activates the function by pressing the SET+ or SET- button. A message is then transmitted via the low speed side of the Controller area network (CAN) to the central electronic module (CEM) which then transmits the message on via the high speed side of the Controller area network (CAN) to the engine control module (ECM).

The engine control module (ECM) controls the throttle angle so that a constant speed is maintained using the vehicle speed signal from the Brake Control Module (BCM). The transmission control module (TCM) also receives a message indicating that cruise control is active via the Controller area network (CAN), so that the transmission follows certain shifting patterns when the cruise control is active.

If the accelerator pedal (AP) is depressed the speed increases as normal and then resumes to the stored value when the driver releases the accelerator pedal (AP) again.

The engine control module (ECM) continually stores the speed. If the cruise control is disengaged, if for example the driver depresses the brake pedal, the previous speed can be resumed by pressing the "RESUME" button.

Cruise control cannot be activated at speeds below 30 km/h.

Cruise control is disengaged

1. when the driver presses the clutch pedal or brake pedal
2. when the driver presses the "CRUISE" button on the steering wheel
3. when the driver depresses the "0" button on the steering wheel
4. if "P" or "N" positions are transmitted on the controller area network (CAN) (applies to automatic transmissions)
5. if the speed deviates too much from the set value
6. when the control system detects a fault that prevents activation.

Scheme 809

The engine control module (ECM) (4/46) regulates the charge voltage of the generator (GEN) (via LIN communication) when requested by the central electronic module (CEM) (4/56) (via CAN communication).

The engine control module (ECM) can change the charge voltage requested by the central electronic module (CEM). to suit certain operating conditions such as engine start, idle speed or high engine load.

The value requested by the engine control module (ECM) for charging voltage and alternator charging current can be read using VIDA (Volvo scan tool).

The alternator control module (ACM) transmits fault information to the engine control module (ECM). Diagnostic trouble codes (DTCs) are stored in the engine control module (ECM).

Scheme 810

The engine control module (ECM) controls the following functions

1. start
2. injectors
3. ignition
4. fuel pressure
5. throttle
6. camshafts (CVVT)
7. evaporative emission system (EVAP) valve
8. engine cooling fan (FC)
9. Air conditioning (A/C) compressor
10. alternator control module (ACM) (2005-).

The engine control module (ECM) is supplied with battery voltage via fuses in the central electronic module (CEM) and in the integrated relay/fusebox in the engine compartment.

To prevent certain stored date from being erased from the engine control module (ECM) when the ignition is switched off, the control module also has a 30-supply. This supply is from the integrated relay/fusebox in the engine compartment.

The control module is grounded via the wiring which is connected at the right-hand suspension turret.

The engine control module (ECM) contains a voltage regulator which maintains a low voltage (5 V) in internal components in the control module such as

1. Analog/Digital converter
2. Digital/Analog converter
3. Micro-processor.

The functions which require battery power and high output are controlled by external or internal power stages. For example ignition coils have external power stages (integrated into the ignition coils) while the power stages for the injectors are integrated into the control module.

The micro-processor in the engine control module (ECM) receives signals from the different sensors and control modules in the vehicle. The micro-processor uses a program which calculates how the signals from the different sensors and other control modules are to be interpreted and how the components / functions need to be controlled.

The control module has several self-learning (adaptive) functions. It continually adapts ongoing calculations to changing circumstances (wear, air leaks, differences between different fuels).

Emissions are kept low through efficient management of the injection period, ignition, evaporative emission system (EVAP) valve and camshafts etc. Faults which affect emissions can be detected by running diagnostics for functions and components.

The engine control module (ECM) is in the intake system. It is cooled by the engine intake air.

The engine control module (ECM) communicates with other control modules using controller area network (CAN) communication.

The engine control module (ECM) checks activations, input and output signals and functions using an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if, after validation, the control module detects a fault. In certain cases the faulty signal is also replaced with a substitute value or certain functions are limited.

For example, substitute values can be set for

1. engine coolant temperature (ECT) sensor
2. mass air flow (MAF) sensor
3. throttle position (TP) sensor
4. air pressure
5. fuel pressure.

Mathematical calculations and signals from certain components are used to calculate the substitute values. Other substitute values are fixed, predefined values in the control module.

The substitute value allows the car to be driven and for the emissions to be kept at a reasonable level even though vital functions/components are malfunctioning.

Functions which may be limited are for example

1. Camshaft control (CVVT)
2. fuel trim
3. throttle angle
4. fuel pressure regulation.

The substitute values are used and functions restricted so that the system is still able to work while protecting components that are required for safety reasons (for example the throttle angle).

Any diagnostic trouble codes (DTCs) are stored in the control module memory. This information can be read off using VIDA (Volvo scan tool) via the data link connector (DLC) in the vehicle.

The table below summarizes the input signals to and output signals from the Engine Control Module (ECM). The signal types are divided into directly connected signals, serial communication and controller area network (CAN) communication. The illustrations below ( (Scheme 811) and (Scheme 812) ) displays the same information with the Volvo component designations.

Scheme 811

Scheme 812

IGNITION SWITCH

The ignition switch powers certain functions in the engine control module (ECM) via fuses in the front integrated relay/fusebox and central electronic module (CEM). The ignition switch also supplies the engine control module (ECM) with signals such as

1. wake up" signal
2. start signal.

wake up" signal

The ignition switch transmits a high signal to the engine control module (ECM) via the central electronic module (CEM) indicating that the ignition switch is in position I or II. The system prepares for start-up (for example by temporarily activating the fuel pump (FP) relay).

Start signal

The ignition switch transmits a high signal to the engine control module (ECM) when the ignition switch is in position III.

The engine control module (ECM) activates the starter motor relay. The relay in turn activates the starter motor.

The fuse in the front integrated relay/fusebox supplies current to the ignition switch.

The central electronic module (CEM) has diagnostics for the ignition switch.

TRANSMISSION CONTROL MODULE (TCM)

The engine control module (ECM) uses a directly connected signal from the transmission control module (TCM) in the start function (activating the starter motor).

IMMOBILIZER

See Immobilizer.

ALTERNATOR CONTROL MODULE (ACM)

See Alternator.

AIR CONDITIONING (A/C) PRESSURE SWITCH

The air conditioning (A/C) pressure sensor detects the pressure in the low pressure side of the air conditioning (A/C) system. See also: REGULATING THE AIR CONDITIONING (A/C) COMPRESSOR

The air conditioning (A/C) pressure sensor has a pressure sensing switch which is supplied powered by the fuse and grounded (signal) in the engine control module (ECM). The air conditioning (A/C) pressure sensor is affected by the pressure in the low-pressure pipe of the air conditioning (A/C) system (thick pipe).

The engine control module (ECM) cannot diagnose the air conditioning (A/C) pressure sensor.

OIL PRESSURE SENSOR (CERTAIN MARKETS ONLY)

The function of the oil pressure switch is to warn the driver about low oil pressure via the driver information module (DIM).

The oil pressure switch has a pressure sensing switch which is powered (signal) by the engine control module (ECM) and grounded in the cylinder block. The oil pressure sensor is affected by the oil pressure of the engine.

When the oil pressure exceeds a certain value, the switch in the oil pressure sensor will open. A high signal is then sent to the engine control module (ECM).

If the oil pressure is below a certain value, the switch in the oil pressure sensor will close and a high signal will be sent to the engine control module (ECM). The engine control module (ECM) then transmits a CAN signal to the driver information module (DIM) to light the indicator lamp for low oil pressure.

The oil pressure sensor is on the cylinder block.

The engine control module (ECM) cannot diagnose the oil pressure sensor.

FUEL PUMP CONTROL MODULE

The fuel pump control module powers the fuel pump and regulates the output of the pump. The fuel pressure changes with the output of the pump.

The fuel pump control module is supplied with battery voltage by the fuel pump (FP) relay and is grounded in the car body. The fuel pump (FP) relay is controlled by the central electronic module (CEM) when requested by the engine control module (ECM).

The engine cannot be started if the power supply to the fuel pump control module is faulty because the fuel pump will not then be powered.

The fuel pump control module is controlled by the engine control module (ECM) via serial communication. The fuel pump control module then controls the fuel pump by transmitting pulse width modulated (PWM) voltage on the ground lead for the fuel pump. This means that the voltage drop across the pump changes, and with it the output of the fuel pump. See also: FUEL PRESSURE REGULATION

There are no diagnostics for the fuel pump control module. The engine control module (ECM) has diagnostics for fuel pressure regulation and the associated components. See also: FUEL PRESSURE REGULATION, DIAGNOSTICS

The pulse-width modulated (PWM) signal from the engine control module (ECM) to the fuel pump control module can be read using VIDA (Volvo scan tool).

The fuel pump control module is on the outside on the right-hand side of the fuel tank.

FUEL PUMP

The function of the fuel pump is to ensure that the pressure is correct at the delivery lines for the injectors when requested by the fuel pump control module.

The fuel pump consists of

1. An electrical pump with an integrated safety valve
2. A pressure equalization valve. This valve equalizes rapid pressure peaks which occur, for example, when the injectors close during engine braking. It also contains a non-return valve which ensures that the pressure in the system does not drop when the engine is switched off
3. Fuel level sensor
4. Fuel filter, cannot be replaced separately
5. Relief valve, releases fuel into the pump housing
6. Ejector pump, continuously fills the pump housing with fuel. The fuel always flows from the fuel pump through the ejector and back to the pump housing.

The fuel pump is supplied with battery voltage by the fuel pump control module and is grounded in the car body via the fuel pump control module.

The engine control module (ECM) has diagnostics for the fuel pump function to ensure that the pressure is correct. See also: FUEL PRESSURE REGULATION, DIAGNOSTICS

The fuel pump can be activated and its status read off using VIDA (Volvo scan tool).

The pressure in the fuel rail can be measured by connecting a manometer to a nipple. This nipple is on the right-hand end of the fuel rail.

BRAKE LIGHT SWITCH

The task of the brake light switch is to provide the engine control module (ECM) with information about the position of the brake pedal.

A signal is transmitted to the engine control module (ECM) when the brake pedal is pressed. The engine control module (ECM) disengages the cruise control (if activated). The brake pedal sensor also disengages cruise control.

The brake light switch is supplied with power from the ignition switch (terminal 30). When the brake pedal is depressed the switch closes and a high signal (12 V) is transmitted to the engine control module (ECM).

The engine control module (ECM) can diagnose the brake light switch. The status of the switch can be read using VIDA (Volvo scan tool).

The brake light switch is on the pedal box by the brake pedal.

A/C PRESSURE SENSOR

The air conditioning (A/C) pressure sensor detects the pressure in the high-pressure side of the air conditioning (A/C) system. See also: REGULATING THE AIR CONDITIONING (A/C) COMPRESSOR

The sensor is linear. It is grounded in the control module and supplied with a 5 Volt current from the control module. A linear signal (between 0-5 V depending on the pressure in the air conditioning (A/C)) is transmitted to the control module. Low pressure produces low voltage, high pressure produces high voltage. The air conditioning (A/C) pressure sensor is affected by the pressure in the high-pressure pipe of the air conditioning (A/C) system (narrow pipe).

The engine control module (ECM) can diagnose the air conditioning (A/C) pressure sensor. The sensor value can be read off using VIDA (Volvo scan tool).

There are two heated oxygen sensors (HO2S), front and rear.

Front heated oxygen sensor (HO2S)

Scheme 813

The front heated oxygen sensor (HO2S) is used to provide the engine control module (ECM) with information about the remaining oxygen content of the exhaust gases in front of the three-way catalytic converter (TWC). This is so that the Engine Control Module (ECM) can continually check the combustion so that lambda=1. lambda=1 is the ideal fuel-air ratio, with 14.7 kg air per 1 kg fuel.

The heated oxygen sensor uses current control and its signal characteristic is linear. With a linear signal characteristic, the amplitude of the signal curve is low when changing the oxygen content in the exhaust gases. The probe consists of a preheating element (see " Pre-heating heated oxygen sensors (HO2S) " below) and the actual lambda sensor. The lambda sensor is an oxygen-sensitive ceramic body consisting of zirconium oxide. The control module supplies power to the ceramic body, which reacts to the oxygen content of the exhaust gases. This in turn affects the signal to the engine control module (ECM). In order to determine the oxygen content in the exhaust pipe, the heated oxygen sensor needs reference air from the surrounding air. This reference air reaches the heated oxygen sensor via the air lines.

The engine control module (ECM) can diagnose the heated oxygen sensor (HO2S). For more information, see: HEATED OXYGEN SENSOR (HO2S) DIAGNOSTIC

VIDA (Volvo scan tool) can be used to read off the calculated lambda value from the heated oxygen sensor.

Rear heated oxygen sensor (HO2S)

Scheme 814

The rear heated oxygen sensor (HO2S) is used to provide the Engine Control Module (ECM) with information about the remaining oxygen content of the exhaust gases behind the three-way catalytic converter (TWC). This information is used by the Engine Control Module (ECM) to check the function of the three-way catalytic converter (TWC). This check is carried out when the conditions for the catalytic converter diagnostics have been met. The rear heated oxygen sensor (HO2S) has no direct effect on regulation of the fuel/air mixture. However the Engine Control Module (ECM) uses the signal to optimize the signal from the front heated oxygen sensor (HO2S). For more information, see: THREE-WAY CATALYTIC CONVERTER (TWC) DIAGNOSTICS

The heated oxygen sensor (HO2S) uses voltage control. The signal characteristic is binary. With a binary signal characteristic, the amplitude of the signal curve changes considerably when changing the oxygen content in the exhaust gases. Otherwise its components and function are the same as the front heated oxygen sensor (HO2S).

The engine control module (ECM) can diagnose the rear heated oxygen sensor. The signal can be read using VIDA (Volvo scan tool).

Preheating of the heated oxygen sensors (HO2S)

The heated oxygen sensor (HO2S) only functions above a certain temperature, approximately 300 °C. The normal operating temperature is between 300-900 °C. The heated oxygen sensors (HO2S) are electrically pre-heated so that operating temperature is rapidly reached. This also ensures that the heated oxygen sensors (HO2S) maintain a normal operating temperature and to prevent condensation which could damage the heated oxygen sensor (HO2S).

The heater element in the probe consists of a positive temperature coefficient (PTC) resistor. The system relay supplies the heater element with voltage. The element is grounded in the engine control module (ECM). When the control module grounds the connection a current flows through the PTC resistor. When the heated oxygen sensor (HO2S) is cold, the resistance in the PTC resistor is low and a large current will flow through the circuit. The current from the Engine Control Module (ECM) is pulsed at first to prevent condensation damage to the heated oxygen sensor (HO2S). Depending on the temperature, allowances are made for factors such as the dew point. As the temperature in the PTC resistor rises, the resistance rises, the current falls and switches in stages to a constant current. The pre-heating time for the front heated oxygen sensor (HO2S) is short, approximately 20 seconds.

Probe preheating begins as soon as the engine is started. The heater element heats the heated oxygen sensors (HO2S) to approximately 350 °C. The probes maintain this as a minimum temperature.

The engine control module (ECM) can diagnose the heater element.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR

The engine coolant temperature (ECT) sensor checks the temperature of the engine coolant. The temperature of the engine coolant is required so that the engine control module (ECM) can regulate

1. the injection period
2. the idle speed
3. the engine cooling fan (FC)
4. the ignition advance
5. engagement and disengagement of the A/C compressor
6. diagnostic functions.

The sensor is a negative temperature coefficient (NTC) type which is supplied with power from the control module (signal) and is grounded in the control module.

The resistance in the sensor changes depending on the temperature of the coolant. Depending on the resistance in the sensor, a voltage (signal) is transmitted to the Engine Control Module (ECM). At 0 °C, the voltage is approximately 4.0 V. At 100 °C the voltage is approximately 0.5 V. Low temperature results in high voltage (high resistance), high temperature in low voltage (low resistance).

The engine coolant temperature (ECT) sensor is located beside the thermostat.

The engine control module (ECM) can diagnose the engine coolant temperature sensor. The sensor value can be read off using VIDA (Volvo scan tool).

ENGINE COOLING FAN (FC) / ENGINE COOLING FAN (FC) CONTROL MODULE

Note. The engine cooling fan may have a post-run of up to approx. 6 minutes after the engine has been turned off. The time for the fan's post-run depends on engine temperature, temperature in the engine compartment and pressure level in the AC-system.

The engine cooling fan (FC) has two functions. One is to cool the engine compartment, the other is to cool the condenser when the air conditioning (A/C) compressor is working.

The engine control module (ECM) transmits a pulse width modulated (PWM) signal to the engine cooling fan (FC) control module. The control module then activates the fan at different speeds. The speed of the engine cooling fan (FC) is determined by the engine control module (ECM), depending on the coolant temperature (based on the signal from the engine coolant temperature (ECT) sensor) and the vehicle speed.

The temperature conditions for engagement of the different engine cooling fan (FC) stages may vary slightly, depending on the engine variant and the equipment level. The temperature conditions apply when

1. the A/C is off
2. no faults are detected by the Engine Control Module (ECM).

The engine cooling fan (FC) and its control module are behind the radiator.

The engine control module (ECM) can diagnose the engine cooling fan. The fan can be activated using VIDA (Volvo scan tool).

Scheme 815

The mass air flow (MAF) sensor gauges the air mass sucked into the engine. It continuously transmits signals to the engine control module (ECM) about the mass of the intake air. This data is used by the engine control module (ECM) to calculate

1. the injection period
2. the fuel pressure
3. the ignition timing
4. turbocharger (TC) boost pressure (turbocharged engines only)
5. the engine load.

The transmission control module (TCM) also uses this data for its gear shift calculations. This data is transmitted to the transmission control module (TCM) from the engine control module (ECM) via the high speed side of the Controller area network (CAN).

The mass air flow (MAF) sensor consists of a plastic housing with connectors, test electronics and an aluminum heat sink. The test electronics in the mass air flow (MAF) sensor consist of a hot film comprised of four resistors. The hot film is cooled by the air flow to the engine.

The mass air flow (MAF) sensor is supplied with battery voltage by the system relay and is grounded in the engine control module (ECM). The signal from the sensor is analog and varies between approximately 1-5 V depending on the air mass. Low air flow (low mass) results in low voltage, high air flow (high mass) gives high voltage. No air flow gives a reading of approximately 1 V.

The mass air flow (MAF) sensor is positioned between the air cleaner (ACL) housing and the intake manifold.

The shape of the mass air flow (MAF) sensor is slightly different on naturally aspirated engines and also contains an air temperature sensor.

The engine control module (ECM) can diagnose the mass air flow (MAF) sensor. The signal can be read using VIDA (Volvo scan tool).

Scheme 816

Overview

The boost pressure sensor is a combined sensor and contains two sensors in the same component

1. manifold absolute pressure (MAP) sensor
2. temperature sensor.

The boost pressure sensor is on the right-hand upper section of the charge air cooler (CAC).

Manifold absolute pressure (MAP) sensor

The manifold absolute pressure (MAP) sensor detects the pressure in the intake manifold downstream of the charge air cooler (CAC). The signal from the sensor is primarily used by the engine control module (ECM) to check that the correct boost pressure is reached. The boost pressure is governed by the turbocharger (TC) control valve.

The sensor, which is a piezo resistor, is grounded in the control module and supplied with 5 V from the control module.

The resistance in the sensor changes depending on the pressure in the intake manifold, giving a signal of 0.5-4.5 V. Low pressure results in low voltage, high pressure on high voltage.

The engine control module (ECM) can diagnose the manifold absolute pressure (MAP) sensor. The sensor signal can be read using VIDA (Volvo scan tool).

Temperature sensor

The temperature sensor detects the temperature of the intake air after the charge air cooler (CAC). This data is used by the engine control module (ECM) to calculate the boost pressure control and to calculate the injection period. The control module also controls certain diagnostic functions using the signal from the temperature sensor.

The sensor, which is an NTC resistor, is grounded in the control module and supplied with power (signal) from the control module.

The resistance in the sensor changes according to the temperature of the intake air. This provides the control module with a signal of between 0.5-5 V. The lower the temperature the higher the voltage (high resistance). A high temperature results in low voltage (low resistance).

The engine control module (ECM) can diagnose the temperature sensor. The sensor signal can be read using VIDA (Volvo scan tool).

ENGINE SPEED (RPM) SENSOR

The engine speed (RPM) sensor provides the Engine Control Module (ECM) with information about the speed and position of the crankshaft. The engine control module (ECM) is able to use the signal from the engine speed (RPM) sensor to determine when the piston in cylinder 1 is approaching top dead center (TDC). However it is unable to use the signal from the engine speed (RPM) sensor to determine whether the piston is in the combustion stroke or whether the exhaust valve is open (exhaust stroke). The signal from the camshaft position (CMP) sensor is also required to determine the operating cycle of the engine.

The signal from the engine speed (RPM) sensor is also used to check the engine for misfires. For more information, see: MISFIRE DIAGNOSTIC

There is a steel ring with stamped holes welded to the rim of the primary section (the section fixed to the crankshaft) of the flywheel.

The holes are positioned with a gap of 6° between each hole. This arrangement creates a hole for each tooth. There are 360° in one revolution. 6° between each hole means that there are 60 holes. However two holes are not stamped, to create a reference position (long gap - missing tooth) for the crankshaft. The first tooth after the reference position is located 84° before TDC on cylinder 1. See: CAMSHAFT CONTROL (CVVT)

The engine speed (RPM) sensor is at the rear of the engine above the flywheel.

The sensor is inductive with a permanent magnet. An alternating current is induced in the sensor when the flywheel/carrier plate passes the engine speed (RPM) sensor. The generated voltage and frequency increases with the engine speed (RPM).

The signal varies between 0.1-100 V depending on the engine speed (RPM).

The Engine Control Module (ECM) is able to determine the engine speed (RPM) by counting the number of holes per time unit. When the reference position passes the engine speed (RPM) sensor, the voltage and frequency drop momentarily to zero, even though the engine is still running. This allows the engine control module (ECM) to determine the position of the crankshaft.

If the signal from the engine speed (RPM) sensor is incorrect or missing, the control module will use the signals from the camshaft position (CMP) sensor, on the condition that the position of the camshaft has been adapted. This means that the car can be driven if the signal is missing.

The engine control module (ECM) can diagnose the engine speed (RPM) sensor. The sensor value (engine speed (RPM)) can be read off using VIDA (Volvo scan tool).

FUEL PRESSURE SENSOR / FUEL TEMPERATURE SENSOR

The fuel pressure sensor is combined and consisted of both the fuel pressure sensor and the fuel temperature sensor. The sensor detects the fuel pressure (the absolute pressure) and the temperature of the fuel in the fuel rail.

The fuel pressure sensor is on the right-hand end of the fuel rail.

Fuel pressure sensor

The pressure sensor is a piezo resistive type resistor, the resistance of which changes with the pressure. Depending on the pressure in the fuel rail, an analog signal of 0-5 V is transmitted. Low pressure results in low voltage, high pressure in high voltage.

The engine control module (ECM) then uses this signal to adjust the pressure in the fuel rail using the fuel pump control module. See also: FUEL PRESSURE REGULATION

The pressure sensor is supplied with 5 V and grounded in the engine control module (ECM). The pressure sensor transmits a signal indicating the fuel pressure to the engine control module (ECM) on a separate cable.

The engine control module (ECM) can diagnose the fuel pressure sensor. Its signals (pressure and temperature) can be read using VIDA (Volvo scan tool).

Note. The absolute pressure is displayed when using VIDA (Volvo scan tool) parameter readout to read off the fuel pressure. If there is no pressure at the fuel rail, the atmospheric pressure will be displayed.

HINT: The relative pressure (absolute pressure minus atmospheric pressure) is displayed when reading off the fuel pressure via a manometer connected to the fuel rail.

Fuel temperature sensor

The temperature sensor is an NTC sensor. The sensor is supplied with voltage (signal) from and grounded in the engine control module (ECM).

The resistance in the sensor changes according to the temperature of the fuel. This provides the engine control module (ECM) with a signal of between 0-5 V. Low temperature results in high voltage (high resistance). High temperature results in low voltage (low resistance).

The engine control module (ECM) uses the signal to calculate fuel density.

CAMSHAFT POSITION (CMP) SENSOR

The function of the camshaft position (CMP) sensor is to detect the flanks of the camshaft rotor. The signal from the sensor is used by the engine control module (ECM) to determine the angle of the camshaft.

Each camshaft has four segments per camshaft revolution. A pulse wheel on the camshaft consisting of four teeth (the teeth are positioned by each flank) is used by the camshaft position sensor (CMP) to detect the segments.

The teeth on the camshaft gear wheel are not equally wide. This allows the control module to determine which flank is detected and therefore which operating cycle the camshaft is in.

When the operating cycle of the camshaft is established, the control module is able to determine which cylinder should be ignited. In the event of misfire or knock in the engine, the control module is also able to determine which cylinder is misfiring or knocking. See also: KNOCK SENSOR (KS) and ENGINE SPEED (RPM) SENSOR

Data about the position of the camshaft is used during camshaft control (CVVT). See also: CAMSHAFT CONTROL (CVVT)

The sensor, which is a magnetic resistor with a permanent magnet, is grounded in the control module and supplied with 5 V from the control module. When one of the teeth on the camshaft pulse wheel passes the camshaft position (CMP) sensor, a signal is transmitted to the control module from the camshaft position (CMP) sensor. The signal varies between 0-5 V and is high when a tooth is in contact with the camshaft position (CMP) sensor and low when the tooth leaves the camshaft position (CMP) sensor.

The camshaft position (CMP) sensor is positioned at the rear of the engine by the controllable camshaft (CVVT).

The engine control module (ECM) can diagnose the camshaft position (CMP) sensor.

Scheme 817

The function of the knock sensor (KS) is to monitor combustion knocking from the engine. Knocking may damage the engine and reduces the efficiency of engine combustion.

If the engine control module (ECM) registers knocking from any of the cylinders, the ignition will be retarded for that cylinder at the next combustion stage. If repeated ignition retardation does not prevent knocking, the injection period will be increased. This has a cooling effect. On turbocharged engines the boost pressure will also be lowered, reducing the engine load.

The sensor is made up of a piezo electrical crystal. If there is engine knock, vibrations (sound waves) spread through the cylinder block to the knock sensor (KS). The resultant mechanical stress in the piezo electrical material in the knock sensors generates a voltage. This signal is transmitted to the Engine Control Module (ECM). The signal corresponds to the frequency and amplitude of the sound waves. This allows the Engine Control Module (ECM) to determine if the engine is knocking. The camshaft position (CMP) sensor and engine speed (RPM) sensor are used to determine the operating cycle of the engine (which cylinder is igniting) and therefore which cylinder is knocking.

The knock sensors (KS) are positioned on the cylinder block below the intake manifold.

Ignition retardation due to knocking can be read using VIDA (Volvo scan tool).

The engine control module (ECM) can diagnose the knock sensors (KS).

Scheme 818

The electronic throttle unit, using the control signal from the engine control module (ECM), regulates the amount of air for engine combustion. This is done using an electronic shutter.

The electronic throttle unit consists of a round throttle disc on a shaft. This is turned using a DC motor (damper motor), gear wheel and two springs, an opening spring and a return spring. The damper motor is controlled by the control module and is supplied with powered by a built in power stage in the control module. At one of the limit positions the throttle disc is closed so that no air can pass the throttle unit. At the other limit position the throttle disc is parallel to the air flow so that the air is able to freely pass through the throttle unit. The throttle disc shaft is mechanically connected to two built-in potentiometers (position sensors) which are supplied with power by the control module. The signals from the potentiometers provide the control module with data about the position of the throttle disc. The throttle unit also has a connector with six gold plated terminal pins.

Note. A damaged pin surface can interfere with the function.

1. Current channels, potentiometers
2. Contact strips, potentiometers
3. Spring
4. Spring
5. Throttle disc
6. Damper motor
7. Gear wheel
8. Gear sector
9. Connector

The throttle unit is located on the engine intake manifold.

In the event of a fault, the throttle unit must be replaced as a single unit.

The engine control module (ECM) can diagnose the electronic throttle unit.

See ELECTRONIC THROTTLE UNIT

Scheme 819

The function of the accelerator pedal (AP) position sensor is to provide the engine control module (ECM) and central electronic module (CEM) with information about the position of the accelerator pedal. This data is used by the engine control module (ECM) to deploy the shutter in the throttle unit to the correct angle.

The sensor consists of a plastic housing with two potentiometers, an AC/DC converter and circuits. The potentiometers are connected to a shaft which is affected by the position of the accelerator pedal (AP). The resistance in the potentiometers changes with the position of the accelerator pedal (AP).

The accelerator pedal (AP) position sensor transmits an analog and a digital signal (pulse width modulated (PWM) signal). The signals give information about the position of the accelerator pedal (AP). The digital signal is generated by the AC/DC converter in the sensor and is transmitted to the engine control module (ECM). The analog signal is transmitted central electronic module (CEM) and on to the engine control module (ECM) via the controller area network (CAN). The analog and digital signals are used at the same time by the engine control module (ECM) to regulate the throttle shutter angle.

The sensor is supplied with 12 V by the system relay via a fuse and is grounded in the car body.

The digital signal is also used in conjunction with the analog signal for accelerator pedal (AP) position sensor diagnostics. The accelerator pedal (AP) position sensor signals can be read off using VIDA (Volvo scan tool). A diagnostic trouble code (DTC) is stored if the engine control module (ECM) detects a difference between the analog and digital signals. The engine control module (ECM) then uses a minimal value to ensure the function (limp home).

The accelerator pedal (AP) position sensor is located on the accelerator pedal bracket.

CLUTCH PEDAL SWITCH

Engine control module (ECM) receives information about the clutch pedal's position in two ways.

Partly from a clutch pedal position sensor which is directly connected to Central electronic module (CEM), and partly from a clutch pedal switch directly connected to the Engine control module (ECM).

The function of the clutch pedal switch is to provide extra safety for the function autostart. In order for the function to be activated, the Engine control module (ECM) must receive signal that indicates pressed down pedal from the clutch pedal switch.

To start without the function autostart it is enough that any of the signals (from clutch pedal position sensor or clutch pedal switch) indicates pressed down pedal.

In its starting position, the clutch pedal switch is open (clutch pedal released). The switch's installation shall be adjusted so that is closed when the clutch pedal passes 75% of full pedal movement.

The clutch pedal switch is on the pedal box by the clutch pedal.

The engine control module (ECM) can diagnose the clutch pedal switch. The status (position) of the switch can be read using the diagnostic tool.

MAIN RELAY (SYSTEM RELAY)

The function of the main relay (system relay) is to supply certain components with voltage.

The relay is mechanical and has a closing and opening function. In the rest position the circuit in the relay is open.

The main relay terminals (#30 and #86) are supplied with voltage by the battery. When the ignition key has been turned and the engine control module (ECM) is powered, the terminal (#85) on the main relay is grounded by the engine control module (ECM).

When the terminal (#85) is grounded, the relay is activated and a number of components are powered via the relay terminal (#87).

The main relay is in the integrated relay/fusebox in the engine compartment and is diagnosed by the engine control module (ECM).

AIR CONDITIONING (A/C) RELAY

The air conditioning (A/C) relay supplies the A/C compressor with voltage. The relay is controlled by the engine control module (ECM) based on information from different signals

1. the climate control module (CCM) (via the control area network (CAN))
2. the engine coolant temperature
3. the position of the accelerator pedal (AP)
4. the pressure in the system.

The engine control module (ECM) can temporarily disengage the A/C compressor during wide open throttle (WOT) acceleration.

The relay is mechanical. It has a closing / breaking function and is supplied with power from the system relay.

In the rest position the circuit in the relay is open.

The system relay supplies the coil and the relay with power. The relay activates when the coil is grounded in the engine control module (ECM), the circuit closes and the A/C compressor is supplied with power via the relay voltage output.

The relay coil is grounded (signal) when the engine control module (ECM) receives a signal via the Controller area network (CAN) from the climate control module (CCM) to activate the relay and start the compressor.

The function of the starter motor relay is to supply power to the starter motor.

The starter motor relay is in the relay/fusebox in the engine compartment.

Scheme 820

The function of the injectors is to spray fuel into the cylinders in the correct spray patterns. This happens sequentially.

The injectors are in the intake manifold.

It is essential that the injectors are correctly installed with no air leakage around them. Fuel leakage from the top of an injector when it is not activated may lead to starting and driving problems.

The engine control module (ECM) controls the injectors by grounding the valves in pulses.

The engine control module (ECM) can diagnose the injectors. The injectors can be activated using VIDA (Volvo scan tool).

EVAPORATIVE EMISSION SYSTEM (EVAP) VALVE

The evaporative emission system (EVAP) valve is used to open and close the connection between the EVAP canister and the intake manifold. The valve controls the flow of hydro-carbons (fuel vapor) from the EVAP canister to the engine intake manifold using the vacuum in the intake manifold. This ensures that hydro-carbons stored in the EVAP canister are used in the engine combustion process.

The valve is an electro-magnetic valve which is powered from the system relay. When the valve needs to be opened, it is grounded internally in the engine control module (ECM). The evaporative emission system (EVAP) valve is closed when in the standby position (open-circuit).

When the control module requests that the EVAP canister should be drained (the hydrocarbons stored in the canister should be released into the engine), the control module deploys the evaporative emission system (EVAP) valve by grounding it. A pulse width modulation (PWM) signal is used to ground the valve and to control the degree to which the valve will open. In this way, the drainage of the EVAP canister is matched to the volumetric efficiency of the EVAP canister, the engine speed (RPM) and the engine load.

The engine control module (ECM) can diagnose the evaporative emission system (EVAP) valve. The valve can be activated using VIDA (Volvo scan tool).

The evaporative emission system (EVAP) valve is close to the intake manifold.

IGNITION COILS

The ignition coils supply the spark plugs with high voltage to produce sparks. The engine control module (ECM) controls the ignition coils so that sparks are generated at the correct time.

Each ignition coil has its own integrated power stage.

The ignition coils are in the sparkplug wells above each spark plug.

The engine control module (ECM) can diagnose the ignition coils.

EMISSIONS WARNING LAMP

The emissions warning lamp in the Driver Information Module (DIM) has a warning symbol. This warning symbol varies depending on the market. The warning symbols are

1. Engine symbol"

The warning lamp lights when the ignition key is turned to position II. The warning lamp will go out after approximately 15 seconds or if the engine is started when no fault is found in the engine management system.

If is not complete (certain diagnostic functions not completed), the warning lamp will flash instead of going out when the ignition key is in position II.

The warning lamp will light if there is a fault in one of the parameters in the engine management system. The warning lamp will also light in response to a request transmitted via the control area network (CAN) if there is a fault in the transmission control module (TCM) which affects emissions.

In the event of emissions related diagnostic trouble codes (DTCs), a counter counts down to determine when to light the malfunction indicator lamp (MIL). The conditions for lighting the malfunction indicator lamp (MIL) vary depending on which diagnostic trouble code (DTC) is stored.

When replacing the engine control module (ECM), the hardware number on the control module is read and transmitted to the Volvo central database. The software is compiled depending on the configuration of the vehicle (for example, structure week and hardware number). The software is then transmitted to VIDA (Volvo scan tool) and downloading is carried out.

A vehicle identity check, a read off of the vehicles' new configuration for updating the Volvo central database and programming of codes are included in the download sequence. The procedure when updating software is identical except that the hardware number is not read but taken directly from the Volvo central database.

The engine control module (ECM) is included in the immobilizer system and a number of conditions must be met for the control module to approve a start.

Immobilizer code: During a start attempt, the central electronic module (CEM) transmits its immobilizer code and the engine control module (ECM) compares this with its own programmed code. This condition is met if the codes correspond.

Serial number: The serial number for the brake control module (BCM) is programmed into the engine control module (ECM). During a start attempt the engine control module (ECM) transmits a query to the brake control module (BCM) about which serial number it has programmed in and then compares this with the serial number programmed into the engine control module (ECM). This condition is met if the serial numbers correspond.

Both conditions must be met to allow a start. When replacing the engine control module (ECM), both the immobilizer code and serial number are programmed in automatically when downloading software.