Electronic Modules - Design and Function: Other Volvo XC90 I

CLIMATE CONTROL MODULE (CCM)

The climate control module (CCM) has a built-in diagnostic system which continuously monitors internal functions and input and output signals.

READING OFF INPUT AND OUTPUT SIGNALS

Using this function, the status or value of parameters can be read off. The presentation of the status or value can be obtained graphically or digitally.

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

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.

For further information, see FROZEN VALUES CLIMATE CONTROL MODULE, DESCRIPTION .

EXPLANATION

Not all the parameters described need to be implemented in the control module. This varies from system to system.

Parameters can also vary depending on which type of climate control module the car is equipped with.

Frozen values are parameter values that are stored when a diagnostic trouble code (DTC) is stored.

BATTERY VOLTAGE, VALUE

Measurement range: 0-18 V

Normal value when the generator (GEN) is charging: 13.0-14.5 V

The value indicates the voltage at the climate control module. Delayed X supply means that voltage supply is retained for 1 minute after the ignition is switched off. Activation of functions such as blower fan run-on and damper motor self-adjustment must be possible during this time.

DISTANCE, VALUE

Indicates the total mileage of the vehicle. The value is given in km.

TIME, VALUE

The value displays the time that has passed since the diagnostic trouble code (DTC) was stored.

FAN CURRENT, VALUE

Measurement range: 0-10 mA

The climate control module calculates the value based on the signal from the control knob for the blower fan. With electronic climate control, the value is also affected by automatic climate control (AUTO position).

The value is used to control the power supply from the power unit to the blower fan motor.

FAN SWITCH, VALUE

Measurement range: 0-100 %

The value indicates the control signal from the climate control module to the blower fan motor.

PASSENGER COMPARTMENT TEMPERATURE, VALUE

Measurement range: -40 to +85 °C

The climate control module calculates the temperature based on the signal from the passenger compartment temperature sensor.

The value is used to control the passenger compartment temperature and as the input signal to the central electronic module (CEM).

FAN LEVEL, VALUE

Measurement range: 0-7 step

The value indicates the position of the blower fan switch and is used by the climate control module to calculate the control signal to the blower fan motor.

VOLTAGE FAN, VALUE

Measurement range: 1-5 V

The value indicates the position of the blower fan switch and is used by the climate control module to calculate the control signal to the blower fan motor.

LEFT TEMPERATURE DAMPER MOTOR, STATUS

The status displays if the damper motor is activated or not.

Off = not activated

On = activated

RIGHT TEMPERATURE DAMPER MOTOR, STATUS

The status displays if the damper motor is activated or not.

Off = not activated

On = activated

RECIRCULATION DAMPER MOTOR, STATUS

The status displays if the damper motor is activated or not.

Off = not activated

On = activated

DAMPER MOTOR FLOOR / VENTILATION STATUS

The status displays if the damper motor is activated or not.

Off = not activated

On = activated

DAMPER MOTOR, DEFROSTER, STATUS

The status displays if the damper motor is activated or not.

Off = not activated

On = activated

ENGINE RUNNING, STATUS

The status displays if the engine was running when the diagnostic trouble code (DTC) was stored.

No = engine not running

Yes = engine running

PULSES FROM THE TEMPERATURE SENSOR FOR THE FAN MOTOR, VALUE

Measurement range: 0-15 pulses/65 ms

The value indicates the speed of the fan for the passenger compartment temperature sensor. The standard number of pulses is 12-13/65 ms.

TEMPERATURE, VALUE

Measurement range: -60 to +195 °C

The value indicates the engine coolant temperature (ECT). The climate control module uses the value to control the blower fan during cold start when AUTO is selected.

OUTSIDE TEMPERATURE, VALUE

Measurement range: -40 to +80 °C

The climate control module obtains the value via the control area network (CAN) from the passenger door module.

The value is used to control the passenger compartment temperature.

EVAPORATOR TEMPERATURE SENSOR, VALUE

Measurement range: 0-5 V

The climate control module uses the value from the evaporator temperature sensor to calculate the temperature.

The value is used to control the air conditioning (A/C) compressor. The compressor is switched off when there is a risk of freezing.

AIR CONDITIONING (A/C), STATUS, COMPRESSOR STATUS

The status displays if the compressor was running when the diagnostic trouble code (DTC) was stored.

Off = compressor off

On = compressor on

LINEAR PRESSURE, VALUE

Measurement range 0-3100 kPa

The value indicates the pressure in the compressor.

VOLTAGE, PASSENGER COMPARTMENT TEMPERATURE SENSOR, VALUE

Measurement range: 0-5 V

The climate control module uses the value from the passenger compartment temperature sensor to calculate the passenger compartment temperature. The value is used as a compensation parameter to control the passenger compartment temperature.

SUN SENSOR, SENSOR SIGNAL, VALUE

Measurement range: 0-5 V

The climate control module uses the value from the sun sensor to calculate the sun intensity. The value is used as a compensation parameter to control the passenger compartment temperature.

TWILIGHT SENSOR, SENSOR SIGNAL, VALUE

Measurement range: 0-5 V

The climate control module uses the value from the twilight sensor to calculate the degree of darkness. The value is used to control the strength of the lighting of the button LEDs.

TEMPERATURE DAMPER MOTOR, LEFT POSITION, VALUE

Measurement range: 0-100 %

The value indicates how much the damper is open.

The climate control module calculates the value based on the stage movement of the damper motor.

DAMPER MOTOR, TEMPERATURE RIGHT POSITION, VALUE

Measurement range: 0-100 %

The value indicates how much the damper is open.

The climate control module calculates the value based on the stage movement of the damper motor.

RECIRCULATION DAMPER MOTOR POSITION, VALUE

Measurement range: 0-100 %

The value indicates how much the damper is open.

The climate control module calculates the value based on the stage movement of the damper motor.

FLOOR / VENTILATION DAMPER MOTOR POSITION, VALUE

Measurement range: 0-100 %

The value indicates how much the damper is open.

The climate control module calculates the value based on the stage movement of the damper motor.

DAMPER MOTOR DEFROSTER POSITION, VALUE

Measurement range: 0-100%

The value indicates how much the damper is open.

The climate control module calculates the value based on the stage movement of the damper motor.

AUTOMATIC BREAKER, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

FLOOR, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

DEFROSTER, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

MAX DEFROSTER, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

AIR CONDITIONING (A/C) ON, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

AIR CONDITIONING (A/C) OFF, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

RECIRCULATION ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

VENTILATION, ACTIVATED, STATUS

The status displays if the signal from the air distribution selector to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

SEAT HEATER LEFT FRONT ACTIVATED, STATUS

The status displays if the signal from the seat heater to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

SEAT HEATER RIGHT FRONT ACTIVATED, STATUS

The status displays if the signal from the seat heater to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

DEFROSTER / HEATED REAR WINDSHIELD, ACTIVATED, STATUS

The status displays if the signal from the defroster / heated rear windshield to the climate control module was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

SENSOR SIGNAL, AIR QUALITY SENSOR (AQS), STATUS

The climate control module interprets the pulse width of the air quality sensor and presents it as different levels.

Off

Level 1

Level 2

Level 3

AIR QUALITY SENSOR PULSE WIDTH, VALUE

Measurement range 0-100 %

The climate control unit calculates the air quality using the signal from the air quality sensor. The value is used to control the position of the recirculation motor.

DASHBOARD ENVIRONMENT PANEL, BUTTON IDENTITY, STATUS

The status indicates the function of the button.

The following alternatives are available

1. Empty position Adjustable head restraints Folding door mirrors Private locking STC DSTC Auxiliary lamps Reduced alarm Bi-fuel Child-proof lock.

DASHBOARD ENVIRONMENT PANEL, BUTTON ACTIVATED, STATUS

The status displays if the button was activated when the diagnostic trouble code (DTC) was stored.

Yes = activated

No = not activated

DASHBOARD ENVIRONMENT PANEL, BUTTON STATUS

The status displays if the function for the button corresponds to the configuration for the central electronic module (CEM).

Unknown = the status could not be determined

Not permitted = the button function does not correspond to the configuration of the central electronic module

Permitted = the button function corresponds to the configuration of the central electronic module

CARCONFIGSTATUS, ADJUSTABLE HEAD RESTRAINT, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, FOLDING DOOR MIRRORS, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, BIFUEL, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, PRIVATE LOCKING, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, STC (STABILITY AND TRACTION CONTROL), STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, DSTC (DYNAMIC STABILITY AND TRACTION CONTROL), STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, AUXILIARY LAMPS, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, REDUCED ALARM, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

CARCONFIGSTATUS, CHILD-PROOF LOCK, STATUS

The status displays whether the identity of a certain switch is permissible or missing compared with the permitted switch identities in the Car Configuration File.

Not defined = comparison failed

Not permitted = identity not permitted

OK = identity permitted

Button missing = button missing on the dashboard environment panel in comparison to the information in the Car Config File

DOWNLOADING SOFTWARE AND REPLACING THE CONTROL MODULE

New software can be downloaded into the climate control module. When ordering software, the hardware and the software in the car is compared to 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 entire climate control module must be replaced as one unit. The exceptions are the fan for the passenger compartment temperature sensor and the switches on the lower section of the dashboard environment panel.

Five customer parameters can be programmed into the climate control module. These customer parameters are stored in the control module but not in the Volvo central database. This means that the customer parameters must be reprogrammed when the hardware is replaced.

Scheme 26

The way in which the climate in the passenger compartment is regulated depends on the type of climate control module (CCM) in the car.

Electronic climate control

Electronic climate control means that either manual settings or the AUTO function can be used. In the latter case the control module automatically regulates heat, air conditioning, recirculation and air distribution until the selected temperature is achieved.

Manual climate control

Manual climate control means that heat, air conditioning, recirculation and air distribution must be selected manually.

STD

STD means that heat, recirculation and air distribution must be selected manually.

The climate control module (CCM) (3/112) regulates the following

1. Activation of the air conditioning (A/C) compressor (8/3) with a request via the Controller area network (CAN) to the engine control module (ECM) (4/46)
2. Controlling the damper motors. For electronic climate control (6/48), (6/95), (6/96), (6/102) and (6/103). For manual climate control; (6/48), (6/69), (6/95) and (6/96)
3. Blower fan speed (6/28).

The climate control module (CCM) regulates the climate in the passenger compartment based on the following input signals

1. The passenger compartment temperature, signal from the internal passenger compartment temperature sensor
2. The outside temperature, signal from the outside temperature sensor (7/11)
3. The evaporator temperature, signal from the evaporator temperature sensor (7/41)
4. Sun roof status. Signal from the sun roof control module (4/33) via the upper electronic module (UEM) (4/70) over the Controller area network (CAN)
5. Side window status. Signals from the driver door module (DDM) (3/126) and passenger door module (PDM) (3/127) via the Controller area network (CAN)
6. Door status. Signal from the central electronic module (CEM) (4/56) via the Controller area network (CAN)
7. Sun intensity. Signal from the sun sensor (7/12)
8. Speed. Signal from the brake control module (BCM) (4/16) (previously ABS), via the Controller area network (CAN)
9. Windshield wiper status. Signal from the steering wheel module (SWM) (3/130) via the Controller area network (CAN).

The climate control module (CCM) (for electronic climate control) uses information about the status of the sun roof, side windows and doors to determine how it should compensate for changes in the passenger compartment temperature. If side windows, doors or the sun roof are opened, the climate control module (CCM) will not compensate for a change in passenger compartment temperature. Instead it maintains the same level of climate control for the compressor and blower fan as before.

The climate control module (CCM) (for electronic climate control) uses the signal from the steering wheel module (SWM) to establish whether the windshield wipers are switched on. This is to regulate the blower fan and the damper motor to remove any mist from the inside of the windshield when it rains.

The climate control module (CCM) (for electronic climate control) uses the signal from the sun sensor to compensate for high sun intensity by decreasing the temperature of ventilation air, changing air distribution and increasing the speed of the blower fan.

The climate control module (CCM) (for electronic climate control and manual climate control) uses the signal from the evaporator temperature sensor to control the activation of the air conditioning (A/C) compressor. If the signal from the evaporator temperature sensor indicates an evaporator temperature below 6 °C, the compressor cannot be activated because of the risk of freezing.

To maintain a constant flow of air in the passenger compartment the climate control module (CCM) (for electronic climate control) uses the speed signal from the brake control module (BCM) to regulate the speed of the blower fan. Generally, as the speed of the car increases the speed of the blower fan decreases.

At higher speeds the flow of air into the fresh air damper is adjusted.

Scheme 27

The seat heaters are activated by pressing the switches on the climate control module (CCM) (3/112). The climate control module (CCM) transmits information via the Controller area network (CAN) about the status selected for each seat to the central electronic module (CEM) (4/56). The central electronic module (CEM) then transmits the information to the relevant control module for seat heating (4/201, 4/202). The control modules for the seat heaters then control the current to the heater pad for the left-hand seat (9/16, 9/18) and right-hand seat (9/17, 9/19).

The central electronic module (CEM) also transmits information to the climate control module (CCM) about whether the seat heaters are activated or not. The climate control module (CCM) uses this information to light / turn off the LEDs on the buttons.

Scheme 28

The climate control module (CCM) (3/112) controls the recirculation during the following conditions for electronic climate control

1. The recirculation switch is on (the LED lights orange)
2. The system is in AUTO position and there is a large difference between the desired and current temperature
3. The car is equipped with an air quality sensor, and the recirculation switch is on (the LED light green).

The air quality sensor transmits a signal to the climate control module (CCM) if it detects high concentrations of pollutants in the outside air. When this occurs the climate control module (CCM) transmits a signal to the damper motor for recirculation (6/48) to close the fresh air damper and to use recirculated air. The level of recirculation is controlled by the signal from the air quality sensor

1. signal 1 provides partial recirculation for speeds below 85 km/h, no recirculation for speeds exceeding 85 km/h
2. signals 2 and 3 provide 100% recirculation.

If the high level of pollutants remains the system stays in recirculation for a certain time, maximum of 10 minutes. The time that the system is recirculating is determined by the outside temperature, if the air conditioning (A/C) is on and if the windshield wipers are activated. The system returns to fresh air for a short time before recirculation is resumed. The particle filter absorbs most of the pollutants entering the passenger compartment during this time. The maximum time prevents misting and musty air.

The air quality transmits information about the content of pollutants to the climate control module (CCM). This information is graded into four levels, and the information used for diagnosis.

Recirculation is never permitted if the defroster is selected. The climate control module (CCM) requests the compressor when the evaporator temperature exceeds 3 °C.

Scheme 29

The heated rear windshield and door mirrors are activated by pressing the switch on the climate control module (CCM) (3/112). The climate control module (CCM) transmits information to the central electronic module (CEM) (4/56) about the selected heating status. The central electronic module (CEM) transmits a signal to the driver's door module (3/126) and passenger door module (PDM) (3/127) for the heated door mirrors and to the rear electronic module (REM) (4/58) for the heated rear windshield.

The central electronic module (CEM) also transmits information to the climate control module (CCM) about whether the seat heaters are activated or not. The climate control module (CCM) uses this information to light / turn off the LED on the button.

SWITCH FUNCTIONS, DASHBOARD ENVIRONMENT PANEL, (LOWER SECTION)

The following functions can be activated using the switches on the dashboard environment panel

1. Folding head restraint, rear seat (S60/S80)
2. Folding door mirrors (market dependent)
3. Bi-fuel, on / off (market dependent)
4. Valet lock, on/off
5. Child lock, on / off (market dependent)
6. STC, off / on (option)
7. DSTC, off / on (option)
8. Auxiliary lamps, off / on (option)
9. Reduced alarm, on / off (option).

In order for certain functions to be activated the engine must be switched on and/or the master key must be in position II.

Folding head restraints, rear seat

When the switch for the folding head restraints is activated, information is transmitted by the climate control module (CCM) (3/112) to the rear electrical module (4/58) via the Controller area network (CAN).

Folding door mirrors

When the switch for the folding door mirrors is activated, information is transmitted by the climate control module (CCM) to the driver's door module (3/126) and the passenger door module (PDM) (3/127) via the Controller area network (CAN).

Bi-fuel

When the bi-fuel switch is activated, a signal is transmitted from the climate control module (CCM) to the engine control module (ECM) (4/46) on the Controller area network (CAN) via the central electronic module (CEM). The engine control module (ECM) transmits a signal to the climate control module (CCM) about the type of fuel being used. The climate control module (CCM) uses this signal to light / turn off the LED on the switch.

Valet lock / child-proof lock

When activating the valet lock switch or the child lock switch information is transmitted to the rear electronic module (REM) via the Controller area network (CAN).

STC or DSTC

When the STC or DSTC switch is activated, a signal is transmitted from the climate control module (CCM) to the brake control module (BCM) (previously ABS) (4/16) via the Controller area network (CAN). The brake control module (BCM) transmits a signal to the climate control module (CCM) about whether the STC or DSTC functions are operating. The climate control module (CCM) uses this signal to light / turn off the LED on the switch.

Auxiliary lamps

When the auxiliary lamps switch is activated, information is transmitted from the climate control module (CCM) to the central electronic module (CEM). The central electronic module (CEM) transmits a signal to the climate control module (CCM) about whether the auxiliary lamps are on or not. The climate control module (CCM) uses this information to light / turn off the LED on the switch

Reduced alarm

When activating the reduced alarm switch information is transmitted via the Controller area network (CAN) to the upper electronic module (UEM) and rear electronic module (REM).

Rear A/C

When activating the switch for rear A/C information is transmitted via the Controller area network (CAN) to the rear electronic module (REM). From this signal and the signal from the engine control module (ECM) indicating whether the engine is running or not, the rear electronic module (REM) will activate/deactivate the relay supply to the rear A/C system. The rear electronic module (REM) transmits a signal indicating whether the rear A/C is on or not to the climate control module (CCM) via the control area network (CAN). The climate control module (CCM) uses this information to light / turn off the LED in the switch.

Scheme 30

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

The climate control module is located in the center console. There are three versions of control module (market dependent). These are

1. Electronic Climate Control. This fully automatic climate control system has air conditioning and the option of manual settings
2. Manual Climate Control. A manual climate control system with air conditioning
3. Standard Heater. A manual climate control system without air conditioning.

The climate control module (for the electronic climate control and manual climate control) obtains the current passenger compartment temperature from a sensor integrated into the control module.

The intensity of the dashboard lighting is regulated based on a signal from the twilight sensor. The twilight sensor is located at the front of the dashboard environment panel under the button for air distribution to the floor.

The climate control module communicates with components which are directly connected and with other control modules and also with components via serial communication and Control area network (CAN).

The control module checks input and output signals and carried out activations via 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 (DTC) are stored in the control module memory. This information can be read off using the diagnostic tool via the data link connector (DLC) in the car.

A simple method for checking that the climate control module has a power supply and is grounded is to increase or decrease the blower fan speed. Another method is to activate one of the functions controlled by the buttons on the dashboard environment panel.

SIGNALS

The table below summarizes input and output signals to and from the climate control module. The signal types are divided into directly connected signals, serial communication and Controller area network (CAN) communication. The illustration below displays the same information with the Volvo component designations.

Scheme 31

Scheme 32

The climate control unit consists of the following components

1. Heater element
2. Damper motor module (DMM), temperature left
3. Blower fan
4. Damper motor module (DMM), fresh air/recirculation
5. Power unit for blower fan motor
6. Particle filter
7. Damper motor module, ventilation and floor (also defroster for MCC)
8. Damper motor module (DMM), temperature right
9. Damper motor module (DMM), defroster (ECC).

Engine coolant constantly flows through the heater element. There is no valve to regulate the flow. The selected temperature is achieved using dampers for the right and left-hand sides of the car installed upstream and downstream of the heater element. These control the amount of air to be warmed. There are also dampers downstream of the heater element that guide the airflow to the correct air vent.

The climate control module provides infinitely variable electronic blower fan control. When AUTO mode (ECC only) is engaged the climate control module (CCM) adapts the blower fan speed to the setting of the controls and the vehicle speed. The blower fan can be set to run-on in order to reduce residual moisture in the evaporator (the function is not available for vehicle's with engine B8444S).

A timer located in the central electronic module (CEM) controls the run-on time. 50 minutes after the engine has been switched off and the ignition has been turned to position 0 or I, the central electronic module (CEM) supplies power to the climate control module (CCM) and the blower fan is activated at full speed for 7 minutes. This run-on dries the evaporator and prevents bad odors.

This function is programmed at the factory, but can be deactivated in the event of customer complaints via programming of customer parameters. Programming is carried out via VIDA (Volvo scan tool).

Scheme 33

The damper motor module (DMM) consists of a control unit and a stepper motor. The different versions of the climate control system have up to 5 damper motor modules (DMM). These are for the different functions such as defroster and recirculation. The climate control module (CCM) communicates with the other damper motor modules (DMM) via two LIN buses, LIN bus 1 and LIN bus 2.

When regulating the different dampers, the climate control module (CCM) transmits a request for a new damper position to the each damper motor module (DMM). The damper motor module (DMM) calculates and then regulates the required direction and number of steps required to obtain the requested position. The damper motor module (DMM) then transmits information to the climate control module (CCM) indicating the actual damper position and status.

When replacing the damper motor module (DMM), the new damper motor must be identified by the climate control module (CCM). This is carried out via VIDA (Volvo scan tool). When replacing the damper motors, ensure that identification is carried out.

Each damper motor module (DMM) is powered via a relay in the central electronic module (CEM).

There are diagnostics for the damper motor module (DMM).

COOLING SYSTEM (NOT B8444S)

The engine control module (ECM) controls the A/C compressor. When the air conditioning (A/C) compressor on the dashboard environment panel is activated, a request is transmitted via the control area network (CAN) to the engine control module (ECM) about the activation of the compressor. The engine control module (ECM) determines when the compressor must operate. If any of the following conditions are met the compressor is disconnected

1. high engine coolant temperature (ECT)
2. wide open throttle (WOT)
3. the engine has just been started
4. overpressure in the air conditioning (A/C) system.

When the engine is started the engine control module (ECM) activates the air conditioning compressor for a short period even if the climate control module (CCM) has not transmitted a request for this. This is carried out for diagnosis. This check is carried out at all temperatures exceeding -6 °C.

The advantage in allowing the engine control module (ECM) to control the air conditioning compressor is that it can delay compressor activation somewhat, if the idling speed must be compensated for the extra load for example.

Scheme 34

The engine control module (ECM) controls the variable A/C compressor. When the A/C switch on the dashboard environment panel is activated, a request is transmitted via the control area network (CAN) to the engine control module (ECM) about the activation of the compressor. The engine control module (ECM) calculates the current to open the valve to control the variable A/C compressor. If any of the following conditions are met, the valve that activates the compressor is not opened

1. high engine coolant temperature (ECT)
2. wide open throttle (WOT)
3. the engine has just been started
4. overpressure in the air conditioning (A/C) system.

When the engine is started the engine control module (ECM) activates the air conditioning compressor for a short period even if the climate control module (CCM) has not transmitted a request for this.

This is carried out for diagnosis and maintenance at all temperatures exceeding 0 °C.

Scheme 35

The evaporator temperature sensor is installed on the heater. Its role is to inform the climate control module (CCM) of the temperature of the refrigerant. The climate control module (CCM) controls the request from the evaporator temperature sensor to activate the air conditioning compressor. The evaporator temperature sensor is directly connected to the climate control module (CCM).

There are diagnostics for the evaporator temperature sensor.

Scheme 36

The air quality sensor (AQS) is available as an option for ECC. The air quality sensor (AQS) is, together with a particle filter, part of a system which has the role of ensuring that the air in the passenger compartment is free of pollutants. The role of the air quality sensor (AQS) is to transmit a signal to the climate control module (CCM) if it detects increased concentrations of pollutants in the outside air.

The air quality sensor (AQS) measures concentrations of COx and NOx.

The air quality sensor (AQS) compares the present values with previous ones and can calculate changes in pollutant concentrations.

The air quality sensor (AQS) communicates with the climate control module (CCM) via a LIN bus.

The signal from the air quality sensor (AQS) to the climate control module (CCM) has four steps, 0-3

1. off = no increase or reduction in pollutant level
2. signal 1 = gradual increase in pollutant level
3. signal 2 = medium increase in pollutant level
4. signal 3 = rapid increase in pollutant level.

The climate control module (CCM) uses the signal to control the recirculation damper motor.

There are diagnostics for the air quality sensor (AQS).

Scheme 37

The system for the seat heaters consists of three different parts

1. a seat heating module (SHM) which controls the function for communicating with the climate control module (CCM)
2. two heater pads
3. a temperature sensor.

The seat heating module (SHM) is under the left and right-hand front seat. The heater pads are in the seat and backrest. The temperature sensor is in the seat.

The seat heating module (SHM) is directly connected to the heater pad and temperature sensor. The seat heating module (SHM) communicates with the climate control module (CCM) via a LIN bus.

There are diagnostics for the seat heating module (SHM).

Scheme 38

Across the lower section of the dashboard environment panel there is a 12V socket and space for a maximum of seven switches.

Each switch has its own identity. This is unique for the relevant function. The switches can therefore be positioned in any location on the dashboard environment panel, as long as they are installed in the off position. They do not have to be in any particular order. However, the identity of the installed switches must correspond with the car configuration file so that they can be activated.

There are diagnostics for the switches.

REAR A/C (ONLY XC90 WITH THREE ROWS OF SEATS)

XC90 with three rows of seats is equipped with a rear A/C system. This consists of

1. power unit
2. fan
3. expansion valve
4. blower fan switch.

The rear A/C system is controlled by a switch in the lower section of the dashboard environment panel. When the switch is activated, the climate control unit (CCM) transmits a signal to the rear electronic module (REM) via the controller area network (CAN). The rear electronic module (REM) supplies the power unit and the blower fan switch with voltage via a relay. The blower fan switch sends control voltage to the power unit based on the position of the control. The power unit converts the control voltage to supply voltage for the blower fan motor.

The rear A/C is directly connected to the front air conditioning via the high and low pressure pipes and hoses. The only way to control the cooling in the third row of seats is to control the fan speed using the rear fan switch.

The rear electronic module (REM) diagnoses the relay supply, otherwise the rear A/C cannot be diagnosed.

The climate control module (CCM) has a built-in diagnostic system which continuously monitors internal functions and input and output signals.

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.

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

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.

For further information, see: DESCRIPTION OF FROZEN VALUES

PROGRAMMING THE CLIMATE CONTROL MODULE (CCM), CUSTOMER ADAPTATION

Certain parameters for the climate control module (CCM) can be read off and programmed using this function. The purpose of this programming is to

1. read the programmed parameters before replacing the control module. This is so the same parameters can be entered into the new control module
2. adapt the function of the control module to the requirements of the driver (customer adaptation)
3. adapt the function of the control module for the equipment levels of the vehicle (passenger compartment ventilation filter, parking heater).

Blower fan run-on, status

Provides the status for activation of the blower fan run-on. The run-on dries the evaporator and prevents bad odors which may otherwise result from residual moisture in the system.

OFF = Run-on inactive

ON = Run-on active (preset)

Air distribution floor/defroster when residual heater is active (NOTE Accessory)

Parameter programming controls the desired setting of air distribution between the floor and defroster when the residual heater is active.

The function means that the coolant can circulate for around 20 minutes after the engine has been switched off. In this way, the passenger compartment can be heated for up to 20 minutes without the engine having to be running. The function is started via the control stalk.

The function can be activated for a further 20 minutes, however, the temperature of the coolant will have cooled considerably and the residual heat will therefore be lower.

Possible settings (70/30% preset)

1. 90/10 (90% floor, 10% defroster)
2. 80/20 (80% floor, 20% defroster)
3. 70/30 (70% floor, 30% defroster)
4. 60/40 (60% floor, 40% defroster)
5. 50/50 (50% floor, 50% defroster)
6. 30/70 (30% floor, 70% defroster)
7. 10/90 (10% floor, 90% defroster).

Programming the seat temperature

Enter the setting for the high and low temperature levels for heating the front seat.

IDENTIFYING THE DAMPER MOTORS

This function is used to identify the damper motor module (DMM) after a replacement. When replacing the damper motor module (DMM), the new unit will have a general identity on the LIN bus. The damper motor module (DMM) must then be run to its limit positions. The number of steps the motor can be run between the limit positions is unique for each damper. This determines the functionality of the new damper motor module (DMM) for the climate control module (CCM).

New software can be downloaded into the climate control module (CCM). 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 entire climate control module (CCM) must be replaced as one unit.

Different customer parameters can be programmed into the climate control module (CCM). These customer parameters are stored in the control module but not in the Volvo central database. This means that the customer parameters must be reprogrammed when hardware is replaced.

For further information about programmable customer parameters, see: DIAGNOSTIC FUNCTIONS

Scheme 39

The way in which the climate in the passenger compartment is regulated depends on the type of climate control module (CCM) in the car.

Electronic climate control (ECC)

Electronic climate control means that either manual settings or the AUTO function can be used. In the latter case the control module automatically regulates heat, air conditioning, recirculation and air distribution until the selected temperature is achieved.

Manual climate control (MCC)

Manual climate control means that heat, air conditioning, recirculation and air distribution must be selected manually.

Climate control module (CCM) (3/112) regulates the following

1. Activation of the air conditioning (A/C) compressor (8/3) using a request via the controller area network (CAN) to the engine control module (ECM) (4/46)
2. Controlling the damper motors. For ECC (6/48), (6/95), (6/96), (6/102) and (6/103). For MCC (6/48), (6/69), (6/95) and (6/96)
3. Blower fan speed (6/28).

The climate control module (CCM) regulates the climate in the passenger compartment based on the following input signals

1. The passenger compartment temperature, signal from the internal passenger compartment temperature sensor
2. Outside temperature, signal from the outside temperature sensor (7/11) via the passenger door module (PDM) (3/127) on the controller area network (CAN)
3. The evaporator temperature, signal from the evaporator temperature sensor (7/41)
4. Sun roof status. Signal from the sun roof control module (4/33) via the upper electronic module (UEM) (4/70) over the controller area network (CAN)
5. Status of the side window, signals from the driver door module (DDM) (3/126) and passenger door module (PDM) (3/127) via the controller area network (CAN)
6. Status of the doors, signal from the central electronic module (CEM) via the controller area network (CAN)
7. Sun intensity, signal from the sun sensor (7/12) via the central electronic module (CEM)
8. Speed, signal from the brake control module (BCM) (4/16) via the controller area network (CAN)
9. Status of the windshield wipers, signal from the steering wheel module (SWM) (3/254) via the controller area network (CAN).

The climate control module (CCM) (for ECC) uses information about the status of the sun roof, side windows and doors to determine how it should compensate for changes in the passenger compartment temperature. If any side windows, doors or the sun roof are opened, the climate control module (CCM) will not compensate for a change in the passenger compartment temperature. Instead it maintains the same level of climate control for the compressor and blower fan as before.

The climate control module (CCM) (for ECC) uses the signal from the steering wheel module (SWM) indicating that the windshield wipers are on. This is to regulate the blower fan and the damper motor to remove any mist from the inside of the windshield when it rains.

The climate control module (CCM) (for ECC) uses the signal from the sun sensor to compensate for high sun intensity. This is done by lowering the temperature of the ventilation air, altering air distribution and increasing the speed of the blower fan.

The climate control module (CCM) uses the signal from the evaporator temperature sensor to control a request for

1. activation of the A/C compressor (not B8444S)
2. control of the A/C compressor (B8444S only)

If the signal from the evaporator temperature sensor displays an evaporator temperature of below 4.5 °C, the compressor is not permitted to run due to the risk of ice formation.

To maintain a constant flow of air in the passenger compartment, the climate control module (CCM) (for ECC) uses the speed signal from the brake control module (BCM) to regulate the speed of the blower fan. Generally, as the speed of the car increases the speed of the blower fan decreases.

At higher speeds the flow of air into the fresh air damper is adjusted.

Scheme 40

The seat heaters are activated using the switches on the climate control module (CCM) (3/112). The function is normally switched off. When activating the seat heaters, the first position is high temperature. If the button is pressed again, the temperature will be low. The status of the indication is displayed via LEDs. The climate control module (CCM) transmits information about the selected temperature to the relevant seat heating module (SHM) on the relevant LIN bus. The seat heating module (SHM) then controls the current to the heater pads.

Each seat heating module (SHM) then transmits its present status to the climate control module (CCM).

Communication between the climate control module (CCM) and each seat heating module (SHM) takes place in the following way

1. seat heating module (SHM), driver's side (9/12) on LIN bus 1
2. seat heating module (SHM), passenger side (9/13) on LIN bus 2.

The climate control module (CCM) receives information from the central electronic module (CEM) (4/56) about the type of seat and upholstery via the controller area network (CAN). The levels for high and low temperature are adapted for the relevant seat and upholstery by the climate control module (CCM). To a certain extent, the levels for high and low temperature can be adapted to the wishes of the customer using VIDA (Volvo scan tool).

Scheme 41

For ECC, the climate control module (CCM) (3/112) controls the recirculation during the following conditions

1. the recirculation switch is on (the LED lights orange)
2. the system is in AUTO mode and there is a large difference between the desired and current temperature
3. the car is equipped with an air quality sensor (AQS), and the recirculation switch is on (the LED lights green).

The air quality sensor (AQS) (7/159) transmits a signal to the climate control module (CCM) if it detects raised concentrations of pollutants in the outside air. When this occurs, the climate control module (CCM) transmits a signal to the damper motor for recirculation (6/48) to close the fresh air damper and to use recirculated air.

The degree of recirculation is controlled by the signal from the air quality sensor (AQS)

1. signal 1 provides partial recirculation for speeds below 85 km/h, no recirculation for speeds exceeding 85 km/h
2. signals 2 and 3 provide 100% recirculation.

If the high level of pollutants remains, the system stays in recirculation for a certain time, maximum of 10 minutes. The time that the system is recirculating is determined by the outside temperature, whether the air conditioning (A/C) is on or if the windshield wipers are activated. The system returns to fresh air for a short time before recirculation is resumed. The particle filter absorbs most of the pollutants entering the passenger compartment during this time. The maximum time prevents misting and musty air.

The air quality sensor (AQS) transmits information about the content of pollutants to the climate control module (CCM). This information is graded into four levels, and the information used for diagnosis.

Recirculation is never permitted if the defroster is selected. The climate control module (CCM) also requests compressor activation when the evaporator temperature exceeds 3 °C.

Scheme 42

The heated rear windshield and door mirrors are activated by pressing the switch on the climate control module (CCM) (3/112). The climate control module (CCM) transmits information via the controller area network (CAN) indicating the status of the electrical heating to the following

1. rear electronic module (REM) (4/58)
2. driver door module (DDM) (3/126)
3. passenger door module (PDM) (3/127).

The following functions can be activated using the switches on the dashboard environment panel

1. Folding head restraint, rear seat (S60/S80)
2. Folding door mirrors (market dependent)
3. Bi-fuel, on / off (market dependent)
4. Valet lock, on/off
5. Child-proof lock, on/off (market dependent)
6. Rear air conditioning (A/C) (XC90, option)
7. STC, off / on (option)
8. DSTC, off / on (option)
9. BLIS, off / on (option)
10. Auxiliary lamps, off / on (option)
11. Parking assistance (option)
12. Reduced alarm, on / off (option)
13. Four-C (Continuously Controlled Chassis Concept), (option).

In order for certain functions to be activated the engine must be switched on and/or the master key must be in position II.

Folding head restraints, rear seat

When the switch for the folding head restraints is activated, information is transmitted by the climate control module (CCM) (3/112) to the rear electrical module (4/58) via the control area network (CAN).

Folding door mirrors

When the switch for the folding door mirrors is activated, information is transmitted by the climate control module (CCM) to the driver door module (3/126) and the passenger door module (PDM) (3/127) via the control area network (CAN).

Bi-fuel

When the bi-fuel switch is activated, a signal is transmitted from the climate control module (CCM) to the engine control module (ECM) (4/46) on the control area network (CAN) via the central electronic module (CEM) (4/56). The engine control module (ECM) transmits a signal to the climate control module (CCM) about the type of fuel being used. The climate control module (CCM) uses this information to light and turn off the LED in the switch.

Valet lock / child-proof lock

When activating the valet lock switch or the child lock switch information is transmitted to the rear electronic module (REM) via the control area network (CAN).

Rear A/C

When activating the switch for rear A/C information is transmitted via the Controller area network (CAN) to the rear electronic module (REM). From this signal and the signal from the engine control module (ECM) indicating whether the engine is running or not, the rear electronic module (REM) will activate/deactivate the relay supply to the rear A/C system. The rear electronic module (REM) transmits a signal indicating whether the rear A/C is on or not to the climate control module (CCM) via the control area network (CAN). The climate control module (CCM) uses this information to light and turn off the LED in the switch.

STC or DSTC (applies to model year -2006)

When the STC or DSTC switch is activated, a signal is transmitted from the climate control module (CCM) to the brake control module (BCM) (4/16) via the controller area network (CAN). The brake control module (BCM) then transmits a signal to the climate control module (CCM) indicating that the STC or DSTC function is on or off. The climate control module (CCM) uses this information to light and turn off the LED in the switch.

BLIS (applies to model year 2007-)

When activating the switch for Blind Spot Information System, the information is transmitted via the CAN network to the Driver door module (DDM) / Passenger door module (PDM). The Driver door module (DDM) / Passenger door module (PDM) transmit the signal to the Climate control module (CCM) about whether the BLIS function is on or off.

The Climate control module (CCM) uses the signal to switch the LED on or off the switch

Auxiliary lamps

When the auxiliary lamps switch is activated, information is transmitted from the climate control module (CCM) to the central electronic module (CEM). The central electronic module (CEM) transmits a signal to the climate control module (CCM) about whether the auxiliary lamps are on or not. The climate control module (CCM) uses this information to light and turn off the LED in the switch.

Back-up warning

When activating the switch for parking assistance, information is transmitted via the Controller area network (CAN) to the rear electronic module (REM).

Reduced alarm

When activating the switch for reduced alarm, information is transmitted via the Controller area network (CAN) to the rear electronic module (REM).

Four-C (Continuously Controlled Chassis Concept)

When activating the switch for Four-C, information is transmitted via the Controller area network (CAN) to the suspension module (SUM).

Scheme 43

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

The climate control module (CCM) is located in the center console. There are two versions of control module (market dependent). These are

1. Electronic climate control (ECC)
2. Manual climate control (MCC).

ECC is a fully automatic climate control system with air conditioning. It also allows manual settings.

MCC is a manual climate control system with air conditioning.

The climate control module (CCM) communicates with components which are directly connected and also with other control modules and components via LIN and CAN communication.

The climate control module (CCM) communicates with the damper motors, air quality sensor (AQS) and the seat heaters via two separate LIN buses. The number of components on the LIN buses varies, depending on the equipment level of the car (ECC/MCC and any accessories).

The following components communicate on LIN bus 1

1. the damper motor module (DMM) for air distribution
2. the damper motor module (DMM) for temperature left
3. the left-hand seat heater.

The following components communicate on LIN bus 2

1. the damper motor module (DMM) for the defroster (ECC only)
2. the damper motor module (DMM) for temperature right
3. the damper motor module (DMM) for recirculation
4. the air quality sensor (AQS)
5. the right-hand seat heater.

The control module checks input and output signals and carries out activations via 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. This information can be read off using VIDA via the data link connector (DLC) in the vehicle.

A simple method for checking that the climate control module (CCM) has a power supply and is grounded is to increase or decrease the blower fan speed. Another method is to activate one of the functions controlled by the buttons on the dashboard environment panel.

The table below summarizes the input signals to and output signals from the climate control module (CCM). The signal types are divided into directly connected signals, LIN and CAN communication. The illustration below displays the same information with the Volvo component designations.

Scheme 44

INFORMATION

GENERAL

Combustion preheater module (CPM) is not a CAN-node, it is a slave node for Central electronic module (CEM), that communicates via serial communication (LIN).

Scheme 45

After initiation, with the ignition key in position II and when the steering wheel is turned 4.5 degrees in any direction, the control module for the steering wheel angle sensor continuously transmits information about the steering wheel angle position to the brake control unit to calculate the driving style of the driver. The brake control module was called ABS-control module up to and including model year 2001.

Communication between the Steering wheel angle sensor control module and the brake control module occurs on the high speed side of the Controller area network (CAN). The control module for the steering wheel angle sensor is positioned on a bracket inside the central electronic module.

The control module for the steering wheel angle sensor is supplied with power from the overload relay.

Scheme 46

The steering wheel angle sensor is incorporated with the SRS contact reel, which in turn is installed on the steering wheel module. The steering wheel angle sensor is equipped with a disc with two code paths. Two circuits with light diodes read off a code path each. One circuit measures the steering angle up to 360 degrees and the other records how many complete turns the steering wheel has turned. Both circuits measure within +/- 700 degrees with a precision of 4.5 degrees. This information is transmitted to the control module for the Steering wheel angle sensor as digital signals.

Due to the reliance of the DSTC (Dynamic stability and traction control) on information from the steering angle sensor it is extremely important that the contact reel has been centered correctly and that only an original Volvo steering wheel is used.

STEERING WHEEL ANGLE

The value displays the steering wheel angle in degrees.

0° = Steering wheel in the straight forward position

1° to 720° = Angle of the steering wheel when turning to the left

1° to -720° = Angle of the steering wheel when turning to the right

LED IY STATUS

The value displays the status of LED IY.

ON = LED IY active

OFF = LED IY not active

LED IX STATUS

The value displays the IX status.

ON = LED IX active

OFF = LED IX not active

LED A STATUS

The value displays the A status.

ON = LED A active

OFF = LED A not active

LED B STATUS

The value displays the B status.

ON = LED B active

OFF = LED B not active

LED R1 STATUS

The value displays the R1 status.

ON = LED R1 active

OFF = LED R1 not active

LED R2 STATUS

The value displays the R2 status.

ON = LED R2 active

OFF = LED R2 not active

LED R3 STATUS

The value displays the R3 status.

ON = LED R3 active

OFF = LED R3 not active

LED R4 STATUS

The value displays the R4 status.

ON = LED R4 active

OFF = LED R4 not active

POWER SUPPLY, STEERING WHEEL ANGLE SENSOR MODULE (SAS)

The value indicates battery voltage at the steering wheel angle sensor module (SAS).

Measurement range: 5 to 15 V

POWER SUPPLY, CENTRAL ELECTRONIC MODULE (CEM)

The value indicates battery voltage at the Central electronic module (CEM).

Measurement range: 5 to 15 V

LED CIRCUIT 1 STATUS

The value displays the status of LED circuit 1

ON = LED circuit 1 is active

OFF = LED circuit 1 is not activate

LED CIRCUIT 2 STATUS

The value displays the status of LED circuit 1

ON = LED circuit 2 is active

OFF = LED circuit 2 is not activate

SIGNAL VOLTAGE, SIGNAL A

The value indicates the signal voltage for signal A.

Measurement range: 0 to 16 V

SIGNAL VOLTAGE, SIGNAL B

The value indicates the signal voltage for signal B.

Measurement range: 0 to 16 V

LED CIRCUIT 1 CURRENT

The value displays the current through LED circuit 1.

Measurement range: 0 to 50 mA

LED CIRCUIT 2 CURRENT

The value displays the current through LED circuit 2.

Measurement range: 0 to 50 mA

SOFTWARE DOWNLOADING

New software can be downloaded into the control module for the Steering wheel angle sensor. When ordering software, the hardware and the software in the car is compared to 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.

Scheme 47

1. Control module for the steering wheel angle sensor
2. Steering wheel angle sensor
3. Reference groove
4. Encoder for steering movements.

Only cars equipped with DSTC (dynamic stability and traction control) have a steering wheel angle sensor control module. The easiest way to determine if a car is equipped with DSTC (Dynamic stability and traction control) is to search for a switch, marked DSTC, positioned in the panel on the climate control module.

The Steering wheel Angle Sensor Module is positioned on the side of the central electronic module. The only function of the steering wheel angle sensor is to process the signals from the steering wheel angle sensor. The signals used by the DSTC system. The steering wheel angle sensor is mounted on the steering wheel module and is directly connected to the steering angle sensor via a connector on the steering wheel module. The Steering wheel angle sensor control module transmits signal information via the high-speed side of the Controller area network (CAN) to the brake control module, model year 2002-or the ABS control module, model year 1999-2001.

If a fault occurs the control module for the steering angle sensor detects this and a diagnostic trouble code (DTC) is stored at the same time as the DSTC function is switched off.

Diagnostic trouble codes (DTCs) stored in the control module for the steering wheel angle sensor. This information can be read off using the diagnostic tool via the data link connector (DLC) in the car.

SIGNALS FOR THE CONTROL MODULE FOR THE STEERING WHEEL ANGLE SENSOR

The table below summarizes input and output signals to and from the Steering wheel angle sensor control module. The signal types are divided into directly connected signals, serial communication and Controller area network (CAN) communication.

BACKGROUND

GENERAL

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 48

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 49

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 for market USA/CDN.

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.

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 50

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 51

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 52

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.

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 53

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

GENERAL

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 54

Graph A illustrates when in time that the malfunction occurs. In the illustration, 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), 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), 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). 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). 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 55

Graph A. 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. 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), 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), 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), 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), 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) 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

GENERAL

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 Diagnoses II is slightly different from status identifiers for diagnostic version Generic Global Diagnostics (GGD).

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

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 56

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 57

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 58

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 59

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 60

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.

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

For further information about parameters, see DESCRIPTION OF PARAMETERS

see DOWNLOADING SOFTWARE AND REPLACING THE CONTROL MODULE

see FUNCTION

see DOWNLOADING SOFTWARE AND REPLACING THE CONTROL MODULE

see FUNCTION

The status for the control module input and output signals can be continuously read off using this function.

For more information on parameters, see: DESCRIPTION OF PARAMETERS

New software can be downloaded into the Differential Electronic Module (DEM). When software is ordered the software and hardware of the vehicle are compared with Volvo's central database. If the comparison corresponds then the software is downloaded into 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.

The control module is fitted on the clutch unit and can be replaced. Control module replacement also involves replacing the control valve/axial solenoid, this is because the control module and control valve/axial solenoid are fitted and calibrated in the factory as one unit.

Scheme 61

1. Oil pressure and temperature sensor
2. Differential Electronic Module (DEM)
3. Control valve/axial solenoid
4. Electrical feed pump

The Differential Electronic Module (DEM) is directly secured onto the clutch unit and together with the axial solenoid and control valve constitutes one unit. Amongst other things the Differential Electronic Module (DEM) communicates with the Engine Control Module (ECM) and the Brake Control Module (BCM) via the Controller Area Network (CAN). Conducted by the sensor signals, the Differential Electronic Module (DEM) controls the oil pressure to the clutch driven plates by adjusting the axial solenoid. The axial solenoid has variable control over the control valve by means of a pulse width modulated (PWM) signal. The basic pressure in the system is built up by the electrical feed pump. The oil pressure to the clutch driven plates is decisive for how much torque can be transferred to the rear wheels.

Note. If the car has dynamic stability and traction control (DSTC), the required stability control is applied before four wheel drive.

Active On demand Coupling (AOC) is equipped with an oil pressure and temperature sensor, which measures the prevailing temperature and pressure in the hydraulic oil. The oil pressure and temperature sensor informs the Differential Electronic Module (DEM) on the temperature and the pressure. If the temperature is too high, above 105 °C, then the four-wheel drive is disconnected to protect the clutch unit from damage. When the temperature falls below 101 °C the clutch unit is reconnected with full functionality.

To protect driveshafts and joints, the Differential Electronic Module (DEM) has functions that reduce the torque that is transferred to the rear wheels in certain situations.

"Trailer detection" is an example of one of these functions. This function is based means that if a trailer is coupled to the vehicle and the driving conditions are such that the front wheels slip on the surface, the Differential Electronic Module (DEM) will transfer less torque to the rear wheels than it would have done without a trailer.

This results in most of the torque remaining on the front wheels, which protects the rear wheel driveshafts and drive joints from extreme loads.

Scheme 62

1. Pressure plate
2. Rollers for axial piston
3. Rollers for working piston
4. Axial piston
5. Working piston
6. Input shaft
7. Cam disc
8. Housing for outer clutch driven plates
9. Outer clutch driven plates
10. Inner clutch driven plates
11. Compression springs
12. Output shaft

The engine torque is transferred to the propeller shaft via the transmission. The input shaft is separated from the output shaft. The disc package must be applied to transfer torque to the rear axle. Inner and outer wet clutch plates are the power transmission points between the input and output shafts.

The cam disc, which is sine shaped, rotates at the same speed as the propeller shaft. The axial piston rollers run on the cam disc's roller coaster and press the axial piston in and out, which creates an oil pressure which acts on the working piston, which in turn applies the disc package.

Scheme 63

1. Cam disc
2. Rollers
3. Pressure valves
4. Pressure limiting valve
5. Control valve cover
6. Oil pressure and temperature sensor
7. Differential Electronic Module (DEM)
8. Control valve/axial solenoid
9. Accumulator
10. Oil strainer
11. Electrical feed pump
12. Oil filter
13. Suction valves
14. Piston pump
15. Working piston
16. Wet disc package
17. Bearings
18. Compression springs

Active On demand Coupling (AOC) can be explained as a hydraulic pump.

The basic pressure in the system is built up by the electrical feed pump. This way the axial pistons are pressurized with oil so that they are pressed against the cam disc via the rollers. The axial piston builds up a working pressure which is conducted to the working piston via the pressure valves. This pressure creates a fixed connection between the input and output shafts. The maximum pressure is limited by the pressure limiting valve. The difference in speed between the input and output shafts is proportional in accordance with the oil pressure to the axial pistons. A large difference in speed between the input and output shafts provides high oil pressure to the axial pistons. The same speed on the input and output shafts provides lower oil pressure to the axial pistons. The oil pressure on the clutch driven plates is controlled by the control valve. The axial solenoid controls the control valve. A closed control valve provides maximum pressure to the clutch driven plates, which provides maximum power transmission. An open control valve provides minimum pressure to the clutch driven plates, which provides a limited power transmission.

The accumulator maintains the basic pressure in the system. The oil filter keeps the oil free from dirt and small particles which can damage the system.

PRETENSIONING

The function of the four-wheel drive system is based in there being a difference in speed between front and rear wheels. This difference in speed can affect traction performance in certain driving situations. The role of the pretensioning function is to improve traction performance, primarily in starting off from being stationary, without affecting other properties of the system to achieve this.

The pretensioning function is obtained by means of the feed pump building up a basic pressure. A pretensioning of the clutch unit is generated by means of this increase in pressure, and the engine torque can be transferred to both rear and front wheels. The pretensioning functionality is controlled by software so that activation only takes place when necessary.

Scheme 64

The most important function of Active On demand Coupling (AOC) and its Differential Electronic Module (DEM) is to control the four-wheel drive function, i. e. power distribution between front and rear axles. The system consists of a clutch assembly with a mechanical, hydraulic and electronic section. The clutch unit is located on the rear axle, between the final drive and the propeller shaft. The mechanical section is driven by the propeller shaft. The hydraulic section is driven by the difference in speed arising between propeller shaft rotation and rear axle rotation.

Active On demand Coupling (AOC) enables the following characteristics

1. Permanent four-wheel drive with electronic control of transferred torque.
2. A driving character equivalent to front-wheel drive.
3. Rapid reactions.
4. No opposing forces when maneuvering or parking.
5. The system is not so sensitive to differences between the tires, e. g. when driving with the spare wheel.
6. Not sensitive to towing with an axle lifted.
7. Not sensitive to brake testing on a chassis dynamometer.

Scheme 65

The hydraulic section consists of 1-5, the mechanical consists of 6-10 and the electronic section consists of 11-13

1. Pressure valves
2. Accumulator
3. Oil filter
4. Ring pistons
5. Control valve/axial solenoid
6. Input shaft
7. Inner and outer wet clutch plates
8. Inner clutch hub with sine shape cam disc
9. Rollers with ring pistons
10. Output shaft
11. Electrical feed pump
12. Differential Electronic Module (DEM)
13. Oil pressure and temperature sensor

The Differential Electronic Module (DEM) is fitted on the clutch unit housing.

The Differential Electronic Module (DEM) communicates with other control modules via Controller Area Network (CAN) communication

The control module has an integrated diagnostic system.

The table below summarizes input and output signals to and from the Differential Electronic Module (DEM). The illustration below displays the same information with the Volvo component designations.

Scheme 66

Scheme 67

The differential electronic module (DEM) is secured directly to the coupling unit's housing and makes up unit with the pressure reducing valve. The control module and the pressure reducing valve are calibrated together at the factory and can therefore only be replaced together.

Via the controller area network (CAN), the differential electronic module (DEM) receives signals from

1. engine control module (ECM).
2. central electronic module (CEM)
3. brake system control module (BCM)
4. driver information module (DIM).

Conducted by these signals, the Differential Electronic Module (DEM) determines how high the oil pressure to the clutch unit should be. The oil pressure to the clutch driven plates is decisive for how much torque can be transferred to the rear wheels.

In case of Differential electronic module (DEM) failure, four-wheel drive may be reduced or lost completely.

Scheme 68

The pressure reducing valve is located in the Differential electronic module (DEM).

The pressure reducing valve receives a constant pulse width modulated (PWM) signal from the control module. The control signal from the control module changes the position of the pressure reducing valve. This regulates the pressure to the discs' operating piston.

In case of diagnostics failure of the pressure reducing valve, four-wheel drive is lost.

The pressure reducing valve can be diagnosed.

Scheme 69

The electric feed pump is located on the clutch unit and is supplied with voltage from the Differential electronic module (DEM).

The pump starts at ignition on and then works up a max. oil pressure of 35 bar. This is to always enable request for full torque. Then the pump is shut off until the pressure has dropped to 50%, then it starts again. If the pump does not reach max. pressure within 15 seconds, it is shut off and is then started again. This is calculated via a current measuring algorithm in the Differential electronic module (DEM). The pump works in intervals so that it is not damaged in case of a malfunction, e. g., leakage, in the system. The time interval that the pump works between depends on the temperature. At normal room temperature the pump runs at approx. 20-30 second intervals.

Four-wheel drive does not function in the event of a fault in the feed pump.

The feed pump can be diagnosed.

Scheme 70

The hydraulic oil is pumped to the accumulator tank via an oil filter. The oil filter keeps the oil free from dirt and small particles that can damage the system. There is a non-return valve installed in the oil filter.

In case of oil filter malfunction, a trouble code may be generated.

The oil filter can be diagnosed

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

New software can be downloaded into the Differential Electronic Module (DEM). When software is ordered the software and hardware of the vehicle are compared with Volvo's central database. If the comparison corresponds then the software is downloaded into 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.

The control module is fitted on the clutch unit and can be replaced. Control module replacement also involves replacing the pressure reducing valve, this is because the control module and pressure reducing valve are installed and calibrated in the factory as one unit.

Scheme 71

1. Differential electronic module (DEM)
2. Electrical feed pump.
3. Oil filter with non-return valve
4. Pressure reducing valve (installed on Differential electronic module (DEM))
5. Disc pack
6. Accumulator tank

Differential electronic module (DEM) is mounted directly on the clutch unit and makes up a unit together with the pressure reducing valve.

Differential electronic module (DEM) communicates with, among others, Engine control module (ECM) and Brake control module (BCM) via the CAN-net. With guidance of the sensor signals, Differential Electronic Module (DEM) controls the oil pressure to the discs through the pressure reducing valve.

The pressure reducing valve is controlled endlessly by a pulse-width modulated (PWM)-signal.

The electric feed pump starts at ignition on and immediately works up a maximal hydraulic pressure in the accumulator. When max. pressure has been reached, the feed pump shuts off until the pressure has dropped below 50% again. Then the feed pump starts again and builds up the max. pressure.

This procedure is calculated by Differential electronic module (DEM) using various parameters. In the accumulator the pressurized oil is routed to the clutch via the pressure reducing valve. Differential electronic module (DEM) controls the valve so that correct working pressure is obtained, 0-27.5 bar. The oil pressure to the discs is decisive to how much torque can be transmitted to the rear wheels.

Scheme 72

1. Output shaft.
2. Input shaft
3. Inner and outer wet clutch plates
4. Operating piston

The transmission and bevel gear transfers engine torque to the propeller shaft. The input shaft is joined to the clutch's output shaft via the multi-plate clutch pack. The multi-plate clutch in the coupling must be engaged to transfer torque to the rear axle. The inner and outer wet multi-plate clutch are the transfer point between the input and output shafts.

The feed pump builds up an oil pressure which then Differential electronic module (DEM) controls via the pressure reducing valve, so that correct pressure is obtained. Then the working piston is applied against the disc pack so that the clearance is eliminated and the clutch is prepared to enable quick reaction and control. At 27.5 bar deployed pressure from the pressure reducing valve max. torque is reached, 1, 500 Nm, through the clutch to the rear wheels already at start.

Scheme 73

1. Bevel gear: Transmits torque from transmission to propeller shaft. Always rotates at the same rate as the front wheel pair.
2. Propeller shaft: Transmits torque from front axle (bevel gear) to rear axle. Always rotates at the same rate as the front wheel pair.
3. Active On demand Coupling (AOC): At four-wheel drive, the AOC transmits torque from the propeller shaft to the rear wheel pair. Rotates at four-wheel drive.
4. Differential gear: Transmits the force to the rear wheel pairs. Rotates at the same rate as the front wheels at four-wheel drive.

Scheme 74

Active On demand Coupling (AOC) and its Differential electronic module (DEM), has as its most important function to control the function for four-wheel drive, that is, power distribution between front and rear axle.

The system consists of an integrated clutch with a mechanical, a hydraulic, and an electronic part.

The clutch unit is located on the rear axle, between the final drive and the propeller shaft. The mechanical part is driven by the propeller shaft. The hydraulic part is driven by an electric pump.

Active On demand Coupling (AOC) generation 4 enables the following characteristics

1. Continuous control of four wheel drive, with electronic control of torque transfer.
2. Rapid reactions
3. No opposing forces when maneuvering or parking.
4. Improved stability.
5. Reduction of oversteering/understeering.
6. Permanent capacity for four-wheel drive.

Scheme 75

1. Accumulator
2. Oil filter
3. Pressure reducing valve
4. Inner and outer wet clutch plates
5. Inner connection hub with splines for output shaft. The hub has a sinusoidal cam curve
6. Input shaft
7. Electrical feed pump.
8. Differential electronic module (DEM)
9. Non-return valve
10. Annular piston

The Differential Electronic Module (DEM) is fitted on the clutch unit housing.

The Differential Electronic Module (DEM) communicates with other control modules via Controller Area Network (CAN) communication

The control module has integrated diagnostics for its own components and functions.

The table below summarizes input and output signals to and from the Differential Electronic Module (DEM). The illustration below displays the same information with the Volvo component designations.

Scheme 76

THE DOOR LOCK

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

Scheme 77

The window lift mechanism on the driver's side is operated via the driver door module (DDM). The window lift mechanism on the passenger side is operated either via the passenger door module (PDM) or via the driver door module (DDM).

The window lift mechanisms in both rear doors can be operated via the driver door module (DDM). The window lift mechanisms in the front and rear doors can be operated when the ignition key is in position I or II. The power windows can be operated from when the ignition is switched off until one of the front doors is opened.

The driver door module (DDM) has four spring loaded switches which operate the individual front and rear windows.

The passenger door module (PDM) has a spring loaded switch which operates the window in the front passenger door. The switches in the driver door module (DDM) which control the rear windows can only be activated up or down. The rear windows move up or down for as long as the switch is activated.

The switches for the front windows 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 windows are powered via the central electronic module (CEM). However they can be disabled using a child lock switch on the driver door module (DDM). When the child lock is activated, the rear windows cannot be operated from the rear seats. They can still be operated however from the driver door module (DDM).

The front window lift mechanisms have a Hall sensor which measures the rotation speed of each lift mechanism, allowing them 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. The power window lift mechanism, power window lift motor and Hall sensor form one unit and cannot be replaced separately.

The window lift mechanisms in the front doors have an inbuilt 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.

Scheme 78

Motors

The motors for the door mirrors are operated via the driver door module (DDM).

The mirrors can be adjusted in the X and Y axes via the two motors for each mirror. Two buttons on the driver door module (DDM), 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-hand 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. 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. This function has been available as an option since structure week 199950.

The door windows can be equipped as an option with a motor that allows the mirror housing to be folded in. The driver door module (DDM) and passenger door module (PDM) have diagnostics for the motor for folding in the door mirrors. However the activation signal is transmitted by the climate control module (CCM).

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

As an option, the door mirrors can be equipped with lights. The lights 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 lights. However the function is activated by the upper electronic module (UEM) and the remote control.

Outside temperature

In the right-hand mirror there is a temperature sensor which measures the outside temperature. This temperature data is used by the combined instrument panel.

Note. This temperature sensor must not be confused with the temperature sensor in the left-hand mirror housing which is used by the engine control module (ECM).

The temperature sensor in the right-hand mirror housing can be replaced separately. The passenger door module (PDM) has diagnostics for the temperature sensor.

Scheme 79

There is a door open warning lamp in each front door which lights when the door is opened. The lamps are supplied with power via the driver door module (DDM) and passenger door module (PDM).

Since structure week 199950 door open warning lamps are no longer installed.

The driver door module (DDM) and passenger door module (PDM) have diagnostics for the door open warning lamps.

DRIVER'S DOOR MODULE

See DIAGNOSTIC FUNCTIONS, DRIVER'S 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 the control module's input and output signals.

The key must not be in the ignition when reading off the status of the door mirror lamp.

Lock cable M1, status, is active while locking the central locking

Lock cable M2, status, is active while unlocking the central locking and / or deadlocks

Lock cable M3, status, is active while locking the deadlocks

The following parameters can be read off

1. The status of the front passenger window up-control
2. The status of the front passenger window down-control
3. The status of the front passenger window auto-control
4. The status of the up-motor for the power window
5. The status of the down-motor for the power window
6. Lock cable M1, status
7. Lock cable M2, status
8. Lock cable M3, status
9. The status of the door open warning lamp (does not apply to all cars)
10. The status of the control for the door mirror
11. Defroster, status
12. Door mirror lamp, status
13. Outside temperature, value NOTE: The outside temperature can only be read off from the control module on the right-hand side of the car.
14. Power supply, value
15. Signal supply, value
16. Door mirror position X axis, value (does not apply to all cars)
17. Door mirror position Y axis, value (does not apply to all cars).

ACTIVATING COMPONENTS AND FUNCTIONS

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

The following components / parameters can be activated in alternative ways

1. The up / down control for the front passenger window
2. Power window motor, up / down
3. Lock cable M1
4. Lock cable M2
5. Door mirror motor
6. Defroster
7. Door mirror lamp
8. Door open warning lamp (does not apply to all cars).

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.

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

The key must not be in the ignition when reading off the status of the door mirror lamp.

Lock cable M1, status, is active while locking the central locking

Lock cable M2, status, is active while unlocking the central locking and / or deadlocks

Lock cable M3, status, is active while locking the deadlocks

The following parameters can be read off

1. The status of the front left window up-control
2. The status of the front left window down-control
3. The status of the front left window auto-control
4. The status of the front right window up-control
5. The status of the front right window down-control
6. The status of the front right window auto-control
7. The status of the rear left window up-control
8. The status of the rear left window down-control
9. The status of the rear right window up-control
10. The status of the rear right window down-control
11. The status of the child safety button NOTE: A diagnostic trouble code (DTC) is stored if the child safety button is activated for 10 seconds.
12. The status of the selection of control for the left door mirror
13. The status of the selection of control for the right door mirror
14. The status of the upward control for the door mirror
15. The status of the downward control for the door mirror
16. The status of the control for the left door mirror
17. The status of the control for the right door mirror
18. The status of the up-motor for the power window
19. The status of the down-motor for the power window
20. Lock cable M1, status
21. Lock cable M2, status
22. Lock cable M3, status
23. The status of the door open warning lamp (does not apply to all cars)
24. Defroster, status
25. Door mirror lamp, status
26. Outside temperature, value NOTE: The outside temperature can only be read off from the control module on the right-hand side of the car.
27. Power supply, value
28. Signal supply, value
29. Door mirror position X axis, value (does not apply to all cars)
30. Door mirror position Y axis, value (does not apply to all cars).

Use this option to activate components / functions in the driver's door module.

The following components / parameters can be activated in alternative ways

1. The up / down control for the front left window
2. The up / down control for the front right window
3. The up / down control for the rear windows
4. The selection of the left or right door mirror control
5. Upwards / downwards / left / right door mirror control
6. Power window motor, up / down
7. Lock cable M1
8. Lock cable M2
9. Door mirror motor
10. Defroster
11. Door mirror lamp
12. Door open warning lamp (does not apply to all cars).

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 driver door module (DDM) and passenger door module (PDM). When ordering software, the hardware and the software in the car is compared to the data 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 re-initialized after the driver door module (DDM) or passenger door module (PDM) is replaced. This is so that the new control module stores the closed position of the window. Initialization is carried out using VIDA (Volvo scan tool).

If the car has power seats with memory for the door mirrors, 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 VIDA (Volvo scan tool). This function can be switched off on cars from model year 2003. This setting will be stored in the control module after deactivation, but not in the Volvo Central Database. This means that the deactivation must be repeated when hardware is replaced.

Scheme 80

Window control is activated via switches on the driver door module (DDM) (3/126) and passenger door module (PDM) (3/127). The motor for the power window on the driver's side (6/58) is controlled directly from the driver door module (DDM). The motor for the power window on the passenger side (6/60) is controlled via CAN communication from the driver door module (DDM) to the passenger door module (PDM). The signals for operating the rear windows are transmitted from the driver door module (DDM) via the controller area network (CAN) to the central electronic module (CEM) (4/56), which manages the rear window functions.

The passenger door module (PDM) only operates the front window on the passenger side. The signal for operating the front passenger window is transmitted from the passenger door module (PDM) to the window lift mechanism motor on the passenger side (6/60).

If the child lock is activated from the driver door module (DDM), the rear windows cannot be operated from the rear seat. When the child lock switch is activated, a signal is transmitted from the driver door module (DDM) on the controller area network (CAN) to the central electronic module (CEM) which disables rear window operation.

FUNCTIONS IN THE DOOR MIRRORS

The functions in the door mirrors (6/62 left) (6/63 right) which are controlled from the driver door module (DDM) (3/126) or passenger door module (PDM) (3/127) are: mirror position adjustment, folding in the mirrors, mirror heating, local lighting/guide lighting, and temperature measurement.

Adjusting the mirror position

Scheme 81

The position of the mirror is controlled using buttons on the driver door module (DDM) (3/126). The driver door module (DDM) 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 from the driver door module (DDM) to the passenger door module (PDM) (3/127) on the Controller area network (CAN).

If the car has power seats with memory for the door mirrors, 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) (4/52) 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 car.

Folding in the door mirrors

Scheme 82

Mirror folding is activated via the switch for folding door mirrors (3/171), which is on the climate control module (CCM) (3/112). A signal is transmitted via the Controller area network (CAN) to the driver door module (DDM) (3/126) and passenger door module (PDM) (3/127). These in turn send the signal on to each door mirror (6/62 and 6/63), which fold each mirror in or out. There is a delay between the button being pressed and the door mirrors folding in or out.

Heating the mirrors

Scheme 83

Mirror heating is activated at the same time as the rear windshield defroster. When the switch for rear demist/mirror demist (3/8) is pressed, the climate control module (CCM) (3/112) transmits a signal to the central electronic module (CEM) (4/56). The central electronic module (CEM) activates the rear demist and transmits a signal to the driver door module (DDM) (3/126) and passenger door module (PDM) (3/127) to activate mirror heating. When the driver door module (DDM) and passenger door module (PDM) receive the signal, the outputs for each door mirror are powered (6/62 and 6/63). The function is switch off at the same time as the rear demist. This can happen in three different ways

1. If the switch for rear demist/mirror demist is pressed again after activation the function is switched off, using a signal from the central electronic module (CEM)
2. The heating switches off automatically 12 minutes after activation. The driver door module (DDM) and passenger door module (PDM) then receive a signal from the central electronic module (CEM) requesting that the function be deactivated
3. The heating is also switched off if the ignition is switched off.

Local lighting/Guide lighting

Scheme 84

The local lighting is activated using the remote control for the car. The function can only be activated when the ignition is off. When the yellow button on the remote control is pressed, the upper electronic module (UEM) (4/70) 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 (10/148) and the lighting for the right door mirror (10/149). The function is deactivated by pressing the button on the remote control again. A signal is then sent from the upper electronic module (UEM) 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-hand control stalk (the key must be removed from the ignition switch). The steering wheel module (SWM) (3/130) then transmits a signal via the controller area network (CAN) to the central electronic module (CEM) (4/56). When the car is then locked, the central electronic module (CEM) sends a signal onwards via the controller area network to the driver door module (DDM) (3/126) and passenger door module (PDM) (3/127), which turn on the lights in the door mirrors (10/148 and 10/149). 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 85

The outside temperature is continuously measured (in ignition positions I and II) by the outside temperature sensor (7/11), which is always in the right-hand door mirror. The analog signal is received by the passenger door module. The signal is converted to a digital signal. This signal is then transmitted on the controller area network (CAN) and used by the central electronic module (CEM) (4/56), which sends the signal on to the driver information module (DIM) (5/1).

Scheme 86

The door open warning lamp function is on cars from between structure weeks 199820 and 199950. The function utilizes the signal transmitted by the central electronic module (CEM) (4/56) on the controller area network (CAN) when a door is opened. The signal is received by the driver door module (DDM) and passenger door module (PDM). The door open warning lamp is then lit in the left (10/60) and right-hand (10/61) front doors. When the door is closed, the central electronic module (CEM) transmits a new signal on the controller area network (CAN). The signal is received by the driver door module (DDM) and passenger door module (PDM) which turns off the relevant door open warning lamp.

Scheme 87

The driver door module (DDM) and the passenger door module (PDM) are broadly similar in terms of functionality. The information in this document is common to both the driver door module (DDM) and the passenger door module (PDM) unless otherwise indicated. 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. Outside temperature measurement
7. Local lighting
8. Door open warning lamp.

The control modules are in their respective doors. The driver door module (DDM) is on the driver's side and the passenger door module (PDM) is on the passenger side. The switches for the power windows are mounted directly on top of the control modules. The appearance and physical versions of the two control modules is different.

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) 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.

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

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 driver door module (DDM) or passenger door module (PDM). The control module is powered and grounded if any of the functions are working.

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

Scheme 88

ILLUMINATION IN DRIVER INFORMATION MODULE (DIM)

Up to and including model year 2003, filament bulbs were used for illuminating the Driver Information Module (DIM). These bulbs can be changed separately.

LEDs have been used for illumination purposes as from model year 2004. If any of the LEDs blow, the entire Driver Information Module (DIM) will have to be changed.

New software can be downloaded into the driver information module. When ordering software, the hardware and the software in the car is compared to 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 does not correspond, the database is updated with the configuration of the car. The software download then begins.

The driver information module is integrated in the combined instrument panel. 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 from the replacement parts catalogue. In the replacement parts catalogue there is software for reloading the driver information module (reloading driver information module) and software for changing to 15 different languages. Reloading reloads the same software that was installed before the control module was replaced.

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

A number of customer parameters can be programmed into the driver information module.

The following data can be programmed into the driver information module. Programming

1. Conditions for the service reminder indicator (SRI) to light, mileage, time and engine hours
2. If the instrument panel should display zeroes for the mileage
3. Unit for temperature. Fahrenheit or Celsius
4. Unit in the trip computer (only applies to cars 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
5. 12 or 24 hour clock display.

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

Scheme 89

In the lower left section of the combined instrument panel (driver information module) (5/1) there is a small window where text messages are displayed. This gives the driver supplementary information for the different warning symbols in order to reduce the number of different symbols in the combined instrument panel. Other types of messages are also displayed, such as the functions of the trip odometer. There is an order of priority where warning signals are displayed first.

Depending on the circumstances, a request for these messages may come from the central electronic module (4/56) or the steering wheel module (3/130). The signals are transmitted via the Control Area Network (CAN).

Scheme 90

The outside temperature gauge is integrated in the tachometer. Its function is to display the outside temperature and to warn the driver when the conditions are icy by displaying a symbol of a snowflake. The snowflake is displayed at a range of -5 to +2 °C.

A sensor which detects the outside temperature is mounted in the right-hand door mirror. The temperature signal is then read off by either the passenger door module (3/127). The value is transmitted via the Control area network (CAN) to the central electronic module (4/56) which then forwards the message to the driver's information module (5/1). The temperature is displayed in Celsius or Fahrenheit, depending on the market, in increments of one degree. The temperature unit can be changed when reprogramming.

Scheme 91

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

The data is transmitted via the control area network (CAN) from the central electronic module (4/56) to the driver information module (5/1).

The customer can adjust the time using a knob on the clock display. The driver information module then transmits the new time to the central electronic module which registers the new data and updates its clock accordingly. The customer can select whether the time will be displayed using the 12 or 24 hour clock. If the 12 hour clock is selected AM or PM is automatically displayed.

Scheme 92

The seat belt reminder reminds the driver to put on the seat belt. There are two versions of the seat belt reminder - European and American. They are slightly different, which is outlined below. The signals which indicate the variant in the car (European or American) are transmitted by the central electronic module (4/56) via the Control Area Network (CAN). Two small symbols light in the upper electronic module (4/70) and indicate when a seat belt is not fastened. The driver information module (5/1) emits an audible signal to warn the driver that no seat belt is fastened. From model year 2002 inclusive, there is also a display on the combined instrument panel (5/1) which warns the driver if their belt is not fastened.

European version

If the seat belt is not fastened when the ignition is switched on, the symbols in the upper electronic module will light and there will be an audible signal from the driver information module. This continues for 6 seconds until either the seat belt is fastened or reverse gear is selected. If the car travels at 10 km/h or more, the audible signal reactivates if the driver has not fastened his/her seat belt.

American version

When the ignition is switched on, the symbols in the upper electronic module will 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 for the same period of time. If the driver releases the belt after fastening it, the audible signal will not resume if more than 6 seconds have passed since the ignition was switched on.

Scheme 93

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. These two can be reset individually. The odometer and one of the two trip odometers are always displayed. The central electronic module (4/56) receives a speed signal from the brake control module (ABS) (4/16) which is transmitted on the high speed section of the Control Area Network (CAN). The central electronic module then transmits the signal on to the driver information module (5/1) via the low speed section of the Control Area Network (CAN). The distance traveled is saved every fourth kilometre and the value is stored in the central electronic module (4/56). Press the button briefly to switch between the two trip odometers. Hold the button in longer to reset the trip odometer. There must be a power supply to the driver information module (5/1) before the odometer can be reset.

SERVICE REMINDER INDICATOR (SRI)

The service reminder indicator (SRI) lights the first time the ignition is switched on after the service interval has been reached. The service reminder indicator (SRI) will continue to light and remain lit for 2 minutes, every time the ignition is switched on until it is reset. The service indicator has changed from model year 2002. The need for a service is indicated partly by a lamp and partly by a text message - "time for service". Previously only the lamp indicated "Service". The service reminder indicator (SRI) can be programmed in three different ways: distance traveled, time since last service and engine hours since last service. The service reminder indicator (SRI) can be reset using VIDA or as follows

Hold down the reset button for the trip odometer and turn the key to position II. Continue holding the button down until the service reminder indicator (SRI) begins to flash. Release the button.

Scheme 94

The engine control module (ECM), (4/46) processes the value from the coolant temperature sensor (7/16). The processed value is then transmitted to the central electronic module (4/56) on the high speed section of the Control Area Network (CAN). The central electronic module 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. If the value is too high a red lamp lights and a text message is displayed outlining the fault.

Scheme 95

A switch is connected to the combined instrument panel (driver information module) (5/1) which detects the incoming signal indicating whether the handbrake is applied or not. The switch is activated and the lamp is lit when the handbrake is applied. This signal is directly connected.

Scheme 96

The supplementary restraint system (SRS) (4/9) contacts the driver information module (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 lights a lamp and displays a text message. The combined instrument panel also informs the supplementary restraint system (SRS) whether the lamp is working or not.

BRAKE WARNING LAMP

The brake control module (4/16) (called ABS module on model years up to and including 2001) informs the driver information module (5/1) via the Control area network (CAN) if there is a fault in the brake system. The driver information module indicates this to the driver by lighting the red general warning lamp and displaying a text message.

The brake fluid level sensor detects the level of the brake fluid in the reservoir. When the level is low, a switch in the sensor closes and the warning lamp lights. This function is directly connected to the driver information module.

Scheme 97

There are two sensors in the fuel tank which transmit signals about the fuel level to the rear electronic module (REM). The rear electronic module (4/58) sends the values on to the driver information module (5/1), which receives the signals, interprets them and displays the fuel level on the fuel gauge. When the fuel level is low a yellow lamp lights to inform the driver.

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 98

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

Information about the vehicle speed comes from the speed sensor which is connected to the brake control module (BCM) (called the ABS module on cars up to and including model year 2001) and the gearbox control module (TCM) (4/28). The brake control module (BCM) (4/16) and the gearbox control module (TCM) calculate an average speed based on the signals sent from the two front wheels by the speed sensors. The calculated speed signal is then transmitted to the central electronic module (CEM) (4/56) from the brake control module and the gearbox control module on the high speed section of the Control Area Network (CAN). Depending on the quality of the signal, the central electronic module uses the signal from the brake control module or the gearbox control module (TCM). The central electronic module then transmits this data on to the driver information module (DIM) (5/1) where it is displayed.

Only cars with automatic gearbox have a gearbox control module (TCM). In cars with manual transmissions, the speed signal is transmitted to the central electronic module by only the brake control module on the high speed section of the Control Area Network (CAN).

TACHOMETER

A flywheel sensor (7/25) is connected to the engine control module (ECM) (4/46). The engine control module (ECM) transmits the engine speed 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) reads the signal from the low speed section of the Control Area Network (CAN). The driver information module receives the value and presents the actual engine speed for the driver.

Scheme 99

The oil pressure sensor (7/6) is connected to the engine control module (ECM) (4/46). The engine control module transmits the oil pressure signal onwards via the high speed section of the Control Area Network (CAN). The central electronic module (4/56) receives the signal, and generates a corresponding signal on the low speed section of the Control Area Network (CAN). If the oil pressure is low, the driver information module (DIM) (5/1) reads the signal from the low speed section of the Control Area Network (CAN). The driver information module indicates this to the driver by lighting a red warning lamp and displaying a text string with explanatory information.

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 WARNING LAMP

The function is to display different "faults" in the car. When a lamp lights this is followed by a text message which presents the driver with additional information about why the lamp has lit. From model year 2002 inclusive the color of the lamp has changed from orange to yellow / red. The lamp lights red in the event of serious faults, or yellow for less serious faults.

MALFUNCTION INDICATOR LAMP (MIL)

The malfunction indicator lamp (MIL) only lights in the combined instrument panel (driver information module) (5/1), if certain emissions related diagnostic trouble codes (DTCs) are stored in the engine control module (ECM) (4/46) or gearbox control module (TCM) (4/28). The signal between the driver information module and engine control module (ECM) is directly connected.

Scheme 100

The most important role of the Driver Information Module is to display the status of the systems in the car for the driver. This covers functions such as

1. Vehicle speed
2. Engine speed
3. Fuel level
4. Engine coolant temperature (ECT)
5. Various warning signals.

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

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

The control module checks 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 driver information module replaces the faulty signal with a substitute signal.

Diagnostic trouble codes (DTC) are stored in the control module memory. The data can be read off using the diagnostic tool.

An easy way of checking that the driver information module is both powered and grounded is to check whether the following warning lamps light when the ignition is switched on: Parking brake, Malfunction indicator lamp and Brake fluid level.

The table below summarizes input and output signals to and from the driver information module. The signal types are divided into directly connected signals, serial communication and Control area network (CAN) communication. The illustration below displays the same information with the Volvo part numbers.

Scheme 101

Scheme 102

Scheme 103

The cylinder head is of the cross-flow type, (Cross-flow = in from one side and out from the other side).

The two camshafts are supported by seven bearing caps each, directly in the cylinder head and camshaft cover. The camshaft cover works like a combined valve cover and camshaft bearing cap. The camshaft cover has cast oil ducts on the underneath which ensure good oil supply to the camshafts and the valve lifters.

The maintenance-free valve lifters, valve springs and valves are in the cylinder head.

Scheme 104

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.

The cylinder head gasket is made of steel and has multiple layers.

For exact adaptation to the relevant piston height there are different thicknesses available. This is to absorb the differences between pistons, connecting rods etc and thereby obtain the correct compression.

Scheme 105

The cylinder block consists of 3 sections.

1. Cylinder block
2. Intermediate section
3. Gear housing

All three sections are made of die cast aluminum, molded under high pressure.

The mating flange between the cylinder block and intermediate section is in the center line of the crankshaft. The gear housing for the camshaft drive is secured on top of the cylinder block.

The cylinder block houses six cast iron cylinder sleeves. These cylinder sleeves cannot be replaced. The stroke length of the cylinders is greater than the cylinder diameter. This produces good torque and competitive power.

The intermediate section's seven main bearing caps have cast iron reinforcements.

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.

Scheme 106

The oil pan is made of die cast aluminum with baffles. This is so that the oil does not splash excessively. Liquid gasket creates a seal between the cylinder block and the oil sump.

The oil pan is designed to reduce mechanical noise from the engine, at the same time as providing a reliable supply of oil at different angles. A composite oil scraper keeps the larger section of the oil volume away from the rotating crankshaft. It minimizes power loss, improves fuel economy and prevents the oil from foaming.

The oil suction line, which runs from the oil pan, is made of plastic. The oil pan is equipped with an oil level sensor.

The oil pan contributes to the rigid design and operates as an extra reinforcement of the cylinder block.

Scheme 107

1. Piston cooling nozzle

The pistons are die cast in aluminum and the connecting rods are forged in steel.

The heat received by the pistons from combustion, is cooled, partly via the coolant jacket in the block but also by the oil from the six piston cooling nozzles.

Scheme 108

The crankshaft is made from forged steel with induction hardened bearing surfaces.

The sprocket is crimped on the crankshaft's rearmost shank.

The crankshaft is supported by seven main bearings. The main bearings are replaceable main bearing shells. The sixth main bearing is a thrust bearing that holds the crankshaft in a determined position along the length of the axle.

An internal vibration damper is on the front end of the crankshaft. Inside the enclosed vibration damper, a circular flywheel works on a silicone fluid, which dampens the crankshaft torsion oscillations. The vibration damper gives longer service life for the crankshaft and smoother engine operation.

The energy that is generated in the vibration damper, is converted to heat, therefore, the unit is cooled with oil via the oil cooler pipe.

Scheme 109

The intermediate shaft is located in the gear housing on the cylinder block. The intermediate shaft drives the camshafts and the auxiliary unit.

There is a sprocket on the rear section of the crankshaft, which drives the intermediate shaft via an intermediate wheel. The intermediate wheel drives the intermediate shaft via the intermediate shaft's centrally mounted gear. The intermediate shaft has a further two gear wheels of different sizes.

The intermediate shaft's front gear wheel has a freewheel clutch that drives the alternator at 2.7 times the engine speed. A free wheel clutch drives in one direction and slips/freewheels in the other direction.

The rear gear wheel drives the overhead camshafts.

Scheme 110

Both camshafts are driven by a camshaft chain, which in turn, is driven by the crankshaft via the intermediate shaft. The camshaft chain has inverted teeth, so called, "silent chain".

The chain drive is maintenance free.

The exhaust side's camshaft has a vibration damper, which guarantees optimum balance in the gear and chain sprockets.

Timing cover

Scheme 111

The timing cover is cast in aluminum.

The coolant pump shell is integrated in the timing cover. This saves weight. The coolant pump is still driven by the auxiliary unit's transmission.

The chain us tensioned by a hydraulic chain tensioner, which is located in the timing cover. Oil injection pipes supply the chain with oil.

Scheme 112

The ideal engine should have low valve lift for low engine RPMs and loads, and high valve lift at high RPMs and loads.

To achieve this, an engine with two completely different camshaft profiles is required.

This engine has a patented system for camshaft profile switching. The system uses two completely different cam profiles designed on the same camshaft.

The inlet camshaft is provided with three cams for each valve, one centrally located with small lift height, 3.6 mm, and two equally sized outer cams with big lift height, 10.0 mm. With a small lift height at low load and at engine speeds up to approx. 3000 rpm, the primary benefit is lower fuel consumption.

In principle, during the time that the lift height is small, the air damper is completely open. Control of the incoming air volume to the cylinders takes place through control of the camshaft's opening times. Hereby the pump losses are reduced, which in turn gives lower fuel consumption.

Low lift

At small lift height (4), only the centrally placed cam acts on the valve, which takes place through the inner valve depressor. The outer cams act on the outer valve depressors, which follow the cams' movement. Since the centrally located valve depressor and the outer depressor are not connected, the outer depressor moves without affecting the valve. Thus, lift height becomes small.

High lift

At high lift height (3), the inner valve depressor is connected with the outer valve depressor with lock pins. The outer camshaft cams' movement is transmitted through the outer valve depressor, on through the lock pins and the inner valve depressor to the valve. Thus, lift height becomes big.

The position of the lock pins is controlled hydraulically with two electro-hydraulic valves. One electro-hydraulic valve controls the valves for cylinders 1, 2 and 4, while the other controls the valve for cylinders 3, 5 and 6. Thus, the electro-hydraulic valves control 6 valves each (as the engine has 2 inlet valves and 2 exhaust valves per cylinder).

The position, on/off, of the electro-hydraulic valves is controlled by the Engine control module (ECM).

The inner valve depressor works like a hydraulic valve depressor, which compensates any wear. Thus the valve clearance is "0".

The exhaust camshaft is conventional and has a lift height of 10.0 mm. The valve depressors are mechanical, that is, they "have" valve clearance.

Scheme 113

The task of the lubrication system is to build-up a protective film of oil between the moving parts of the engine. The lubrication system must also transport dirt particles away from the moving parts and cool hot engine parts.

This is carried out by the oil pump supplying oil to the oil filter through an oil pressure line of treated steel.

Clean oil is supplied to the oil cooler from the oil filter to the oil cooler. From there the oil is further distributed, through a duct system, out to the various engine functions.

A pressure sensitive valve controls the oil flow to the vibration damper's oil cooler pipe if necessary.

Oil pump

Scheme 114

The oil pump is in the oil pan, mounted underneath the intermediate section. The oil pump has an integrated relief valve. The pump is directly driven by the sprocket on the rear end of the crankshaft.

The oil pump draws oil from a centrally located nozzle in the sump.

The pump increases the pressure of the oil for lubrication, cooling and hydraulic functions.

Oil filter module

Scheme 115

The oil filter module consists of an oil filter reservoir and an oil cooler. It is mounted on the intermediate section. The oil filter module is element based and can be taken apart.

The oil cooler is connected to the coolant system. Coolant is led through the oil cooler.

Scheme 116

The coolant pump shell is integrated in the timing cover. The pump wheel is still driven by the auxiliary unit's transmission.

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 coolant 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.

For the turbocharged engine, the task of the cooling system is to supply the turbocharger with coolant.

Scheme 117

The crankcase ventilation is maintained internally in the engine.

An oil separator is on top of the engine's camshaft cover. It separates the oil drops from the air in the crankcase. The drops are collected in a separator and flow back inside the engine to the oil pan. This prevents extra weight and space for external pipes.

Scheme 118

The auxiliary units are located at the upper edge of the cylinder block, above the transmission. They are driven by two systems, a Poly-V-belt driven system and a clutch system. These two systems are driven by the intermediate shaft transmission.

The belt system consists of a 6-ribbed Poly-V belt, an automatic belt tensioner and a guide pulley. This system drives the servo pump and AC compressor. The coolant pump is driven by the servo pump via the clutch system.

TURBOCHARGER (TC)

Note. Only applies to turbocharged engines.

Scheme 119

The exhaust gases enter via the manifold (1) down to the turbine housing (8) and out to the exhaust system via a downpipe and catalytic converter.

The turbine expels the exhaust gases and rotates the compressor wheel (3). 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 via the charge air pipe and charge air cooler.

The electronically controlled By-pass valve (4) then controls the boost pressure in the turbocharger by determining the amount of exhaust gases which must pass the turbine. The turbine transfers drive to the compressor. The wastegate valve (2) is a membrane which equalizes the pressure of the intake and exhaust air to eliminate noise.

The turbocharger is lubricated by the engine's oil system (7). The oil system also acts as a supplement to the coolant system (5 and 6).

Scheme 120

The engine has been developed by Volvo.

It is a 6 cylinder transverse in-line engine with a cylinder capacity of 3.2 L for naturally aspirated engines and 3.0 L for turbocharged engines.

The engine is extremely compact. When it was introduced it was the shortest 6-cylinder engine of 3.2 L on the market. Conventional straight 6-cylinder engines are too long to fit between the collision members in the engine compartment. The special design of this engine solves the problem.

The engine has an extremely short drive train, its length is only 625 mm from the front edge of the engine block to the rear edge of the carrier plate.

Great attention has been paid to creating a very rigid engine. Middle part, cylinder block and cylinder head have been structurally optimized to combine low weight with high rigidity.

Even the camshaft cover is structurally optimized.

The engine has double overhead camshafts and 24 valves.

Camshafts, servo pump, AC-compressor, coolant pump and alternator are driven by an auxiliary unit drive, mounted on the back of the engine.

This placement of the auxiliary unit drive gives completely new possibilities of creating a good collision-protective structure around the straight 6-cylinder drive unit.

The entire engine block and the cylinder head is made from aluminum.

The engine has a compact "pent-roof" designed combustion chamber and V-arranged valves. This gives optimal and fast filling and direct flushing via the inlet manifold followed by the combustion chamber (cross-flow) and the exhaust channel.

The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.

The engine's firing order is 1 - 5 - 3 - 6 - 2 - 4. The firings occur every 120 degrees that the crankshaft rotates.

ENGINE BLOCK

CYLINDER HEAD, CAMSHAFT BEARING HOUSING

The cylinder head is of the cross-flow type, (Cross-flow = in from one side and out from the other side).

The two camshafts are supported by seven bearing caps each, directly in the cylinder head and camshaft cover. The camshaft cover works like a combined valve cover and camshaft bearing cap. The camshaft cover has cast oil ducts on the underneath which ensure good oil supply to the camshafts and the valve lifters.

The maintenance-free valve lifters, valve springs and valves are in the cylinder head.

CYLINDER HEAD GASKET

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.

The cylinder head gasket is made of steel and has multiple layers.

CYLINDER BLOCK

The cylinder block consists of 3 sections.

1. Cylinder block
2. Intermediate section
3. Gear housing

All three sections are made of die cast aluminum, molded under high pressure.

The mating flange between the cylinder block and intermediate section is in the center line of the crankshaft. The gear housing for the camshaft drive is secured on top of the cylinder block.

The cylinder block houses six cast iron cylinder sleeves. These cylinder sleeves cannot be replaced. The stroke length of the cylinders is greater than the cylinder diameter. This produces good torque and competitive power.

The intermediate section's seven main bearing caps have cast iron reinforcements.

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.

Scheme 121

The oil sump is made of die-cast aluminum with baffles (splash walls). This is so that the oil stays in the sump during active driving (heavy braking/acceleration, sharp turns, etc). Liquid gasket ensures the seal between the cylinder block and the oil sump.

The oil pan is designed to reduce mechanical noise from the engine, at the same time as providing a reliable supply of oil at different angles. A composite oil scraper keeps the larger section of the oil volume away from the rotating crankshaft. It minimizes power loss, improves fuel economy and prevents the oil from foaming.

The oil suction line, which runs from the oil pan, is made of plastic. The oil pan is equipped with an oil level sensor.

The oil pan contributes to the rigid design and operates as an extra reinforcement of the cylinder block.

The oil volume for engines B6324S4/S5 and B6304T4 have been reduced by 0.6 litres. Reasons for reducing the oil volume are, among others, lower service costs (cost of ownership), lower friction, and increased power. Lower friction and higher power are attained by facilitating the engine's internal 'breathing' with a lower oil surface, that is, easier evacuation of gases under the pistons.

The change of the oil volume is partly connected to a changed oil scraper plate, which means that the oil system also works with a reduced oil volume, as well as cooling for IVD ( I nternal V iscous D amper), which is removed since 09w11. Since the volume reduction is partly connected to IVD-cooling it is not possible to reduce the oil volume on an older engine with IVD-cooling, even if the new oil scraper plate is retrofitted. Due to the volume reduction, a new oil dipstick is introduced with adapted markings.

Scheme 122

Under the crankshaft there is an oil scraper plate that is to prevent the oil from following along with the crankshaft in the crank movement. The plate is updated and is now located closer to the crankshaft and has integrated drain pipes. With these changes it has been possible to reduce the oil volume.

PISTON

1. Piston cooling nozzle

The pistons are die cast in aluminum and the connecting rods are forged in steel.

The heat received by the pistons from combustion, is cooled, partly via the coolant jacket in the block but also by the oil from the six piston cooling nozzles.

Scheme 123

To further improve the engine's features, a new type of spark plug is used, from Denso. The designation is " SIP " which means S uper I gnition spark P lug.

An SIP-spark plug has a special design which improves a number of features with a more stable spark. By using a special alloy for both the centre and side electrode, these can have a smaller diameter than normally. The smaller diameter of the electrodes minimizes heat losses during the flame build process, concentrates the electric field, and gives a stronger spark. The stronger spark gives higher engine power, improved fuel economy, better cold-cranking performance, and longer service life. It is the same spark plug for all versions of engine B63x4x, and can also be used for older versions. Electrode gap is 1.0 mm.

CRANK SYSTEM

The crankshaft is made from forged steel with induction hardened bearing surfaces.

The sprocket is crimped on the crankshaft's rearmost shank.

The crankshaft is supported by seven main bearings. The main bearings are replaceable main bearing shells. The sixth main bearing is a thrust bearing that holds the crankshaft in a determined position along the length of the axle.

An internal vibration damper is on the front end of the crankshaft. Inside the enclosed vibration damper, a circular flywheel works on a silicone fluid, which dampens the crankshaft torsion oscillations. The vibration damper gives longer service life for the crankshaft and smoother engine operation.

Engine versions without turbo were changed 10w20 with a modified crankshaft. The goal is to reduce the crankshaft's torsion vibrations at high engine speeds (4, 500 rpm and up) and to save weight. The reduced torsion vibration means reduced noise level at high RPMs at the same time as it reduces the load (torque) on the geartrain that drives the camshafts and auxiliary unit drive. It is the crankshaft's forged blank that is changed, reworking is unchanged.

To reduce vibrations material has been added between crank pin and main pin for the rear cylinders, which gives increased stiffness. At the crankshaft's front end, material has been removed instead, to reduce the crankshaft's oscillating mass. A new strategy has been used to design the crankshaft's balance weights to reduce weight. This can be seen by some balance weights having become small while others have become bigger. The changes have reduced the crankshaft's weight by a total of 1 kg. The change does not apply to turbo engines, but can be used on earlier versions of aspiration engines.

Main bearing

Scheme 124

To improve the cold-cranking capacity, all main bearings have a changed appearance. In the middle of the bearing the thickness is unchanged but toward the end of the bearing the thickness is approx. 10μm thinner. The new type of bearing is possible to use on all versions of engine B63x4x, also those built earlier than 10w20.

INTERMEDIATE SHAFT

The intermediate shaft is located in the gear housing on the cylinder block. The intermediate shaft drives the camshafts and the auxiliary unit.

There is a sprocket on the rear section of the crankshaft, which drives the intermediate shaft via an intermediate wheel. The intermediate wheel drives the intermediate shaft via the intermediate shaft's centrally mounted gear. The intermediate shaft has a further two gear wheels of different sizes.

The intermediate shaft's front gear wheel has a freewheel clutch that drives the alternator at 2.7 times the engine speed. A free wheel clutch drives in one direction and slips/freewheels in the other direction.

The rear gear wheel drives the overhead camshafts.

CAMSHAFT TRANSMISSION

Both camshafts are driven by a camshaft chain, which in turn is driven by the crankshaft via the intermediate shaft. The camshaft chain has inverted teeth, so called, "silent chain".

The chain drive is maintenance free.

The exhaust side's camshaft has a vibration damper, which guarantees optimum balance in the gear and chain sprockets.

Timing cover

The timing cover is cast in aluminum.

The coolant pump shell is integrated in the timing cover. This saves weight. The coolant pump is still driven by the auxiliary unit's transmission.

The chain us tensioned by a hydraulic chain tensioner, which is located in the timing cover. Oil injection pipes supply the chain with oil.

VARIABLE CAMSHAFT PROFILE (CPS), ONLY APPLIES TO B6324S5

The ideal engine should have low valve lift for low engine RPMs and loads, and high valve lift at high RPMs and loads.

To achieve this, an engine with two completely different camshaft profiles is required.

This engine has a patented system for camshaft profile switching. The system uses two completely different cam profiles designed on the same camshaft.

The inlet camshaft is provided with three cams for each valve, one centrally located with small lift height, 3.6 mm, and two equally sized outer cams with big lift height, 10.0 mm. With a small lift height at low load and at engine speeds up to approx. 3000 rpm, the primary benefit is lower fuel consumption.

In principle, during the time that the lift height is small, the air damper is completely open. Control of the incoming air volume to the cylinders takes place through control of the camshaft's opening times. Hereby the pump losses are reduced, which in turn gives lower fuel consumption.

Low lift

At small lift height (4), only the centrally placed cam acts on the valve, which takes place trough the inner valve depressor. The outer cams act on the outer valve depressors, which follow the cams' movement. Since the centrally located valve depressor and the outer depressor are not connected, the outer depressor moves without affecting the valve. Thus, lift height becomes small.

High lift

At high lift height (3), the inner valve depressor is connected with the outer valve depressor with lock pins. The outer camshaft cams' movement is transmitted through the outer valve depressor, on through the lock pins and the inner valve depressor to the valve. Thus, lift height becomes big.

The position of the lock pins is controlled hydraulically with two electro-hydraulic valves. One electro-hydraulic valve controls the valves for cylinders 1, 2 and 4, while the other controls the valve for cylinders 3, 5 and 6. Thus, the electro-hydraulic valves control 6 valves each (as the engine has 2 inlet valves and 2 exhaust valves per cylinder).

The position, on/off, of the electro-hydraulic valves is controlled by the Engine control module (ECM).

The inner valve depressor works like a hydraulic valve depressor, which compensates any wear. Thus, the valve clearance is "0".

The exhaust camshaft is conventional and has a lift height of 10.0 mm. The valve depressors are mechanical, that is, they "have" valve clearance.

Scheme 125

Valve depressors without CPS -functionality ( C amshaft P rofile S hifting) have a coating of DLC ( D iamond L ike C arbon).

It is the tops of the valve depressors that are coated with DLC. The layer with diamond-like carbon structure has a depth of 2μm, is very hard and has self-lubricating properties. The surface reduces the friction against the camshaft lobes and thus gives lower fuel consumption and longer service life.

Thanks to very good adhesion and toughness the DLC-coating can handle very high loads. The change applies to valve depressors without CPS-functionality.

This means that it concerns depressors in position

1. Engine B6304T4 (Ulev2) Exhaust, inlet
2. Engine B6324S4 (Pzev) Exhaust, inlet
3. Engine B6324S5 (Ulev) Exhaust

If needed the DLC-coated depressors can also be used on older engines.

Scheme 126

The task of the lubrication system is to build-up a protective film of oil between the moving parts of the engine. The lubrication system must also transport dirt particles away from the moving parts and cool hot engine parts.

This is carried out by the oil pump supplying oil to the oil filter through an oil pressure line of treated steel.

Clean oil is supplied from the oil filter to the oil cooler. From there the oil is further distributed, through a duct system, out to the various engine functions.

A pressure sensitive valve controls the oil flow to the vibration damper's oil cooler pipe if necessary.

Oil pump

The oil pump is in the oil pan, mounted underneath the intermediate section. The oil pump has an integrated relief valve. The pump is directly driven by the sprocket on the rear end of the crankshaft.

The oil pump draws oil from a centrally located nozzle in the sump.

The pump increases the pressure of the oil for lubrication, cooling and hydraulic functions.

Oil filter module

The oil filter module consists of an oil filter reservoir and an oil cooler. It is mounted on the intermediate section. The oil filter module is element based and can be taken apart.

The oil cooler is connected to the coolant system. Coolant is led through the oil cooler.

COOLING SYSTEM

The coolant pump shell is integrated in the timing cover. The pump wheel is still driven by the auxiliary unit's transmission.

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 coolant 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.

For the turbocharged engine, the task of the cooling system is to supply the turbocharger with coolant.

Coolant pump and drive gear

Scheme 127

Alternator/clutch

Scheme 128

The belt pulleys on alternator and intermediate shaft have improved surface treatment.

On the alternator shaft between alternator and intermediate shaft there is a clutch with a freewheel (one-way clutch) at each end. The function is to filter the engine's different irregular shape and thus avoid gear rattle/noise in the geartrain.

In connection with introduction of EHPAS (electric servo pump), the belt-driven servo pump with its heavy steel belt pulley is discontinued as well as the clutch for the coolant pump. The reduced rotating moment of inertia means more freewheeling, primarily when idling.

To reduce/avoid wear, the drive gears' outer ring (against the one-way clutch's friction band), are treated with nitride.

AC bracket

Scheme 129

The AC compressor's fastening bracket is simplified. Earlier solution with a main bracket and three separate stays, is replaced by a modified bracket which has the front reinforcement stay integrated and a new fastening point in the transmission. The change means, except that the fastener assembly has 9 fewer bolts, that the installation method becomes easier and there is no longer a need for any special tools when assembling.

CRANKCASE VENTILATION

The crankcase ventilation is maintained internally in the engine.

An oil separator is on top of the engine's camshaft cover. It separates the oil drops from the air in the crankcase. The drops are collected in a separator and flow back inside the engine to the oil pan. This prevents extra weight and space for external pipes.

AUXILIARY UNIT TRANSMISSION

The auxiliary units are located at the upper edge of the cylinder block, above the transmission. They are driven by two systems, a Poly-V-belt driven system and a clutch system. These two systems are driven by the intermediate shaft transmission.

The belt system consists of a 6-ribbed Poly-V belt, an automatic belt tensioner and a guide pulley. This system drives the servo pump and AC compressor. The coolant pump is driven by the servo pump via the clutch system.

Note. Only applies to turbocharged engines.

The exhaust gases enter via the manifold (1) down to the turbine housing (8) and out to the exhaust system via a downpipe and catalytic converter.

The turbine expels the exhaust gases and rotates the compressor wheel (3). 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 via the charge air pipe and charge air cooler.

The electronically controlled By-pass valve (4) then controls the boost pressure in the turbocharger by determining the amount of exhaust gases which must pass the turbine. The turbine transfers drive to the compressor. The wastegate valve (2) is a membrane which equalizes the pressure of the intake and exhaust air to eliminate noise.

The turbocharger is lubricated by the engine's oil system (7). The oil system also acts as a supplement to the coolant system (5 and 6).

Scheme 130

Exhaust manifold/ CCC ( C lose C oupled C atalyst) and front exhaust pipe/catalytic converter for engine are improved with regards to weight and efficiency. Heat shield plates are modified.

Manifold with catalytic converter

The catalytic converter's cross-section is changed from oval to round, which means better contact pattern of the exhaust flow against the catalytic converter's substrate. This means that the amount of precious metals in the coating on the catalytic converter can be reduced at the same time as the emission standards are fulfilled. In addition to a great cost-saving, reducing the need for precious metals also results in less environmental impact.

The outlet flange is changed from a thickness of 8 mm with threaded holes (x4) to a 4 mm thick plate with press bolts (x4). This gives weight and cost-savings. Gaskets are changed to 1.2 mm flat gaskets.

Downpipe/Catalytic converter

The catalytic converter's inlet flange is also changed from 8 mm to 4 mm thick, which gives a weight and cost-saving. The bellows is more flexible which gives less noise from resonance and vibrations as well as longer service life. Also, the rear catalytic converters have a reduced amount of precious metals in the substrate's coating at the same time as the emission standards still are fulfilled, which gives another big cost-saving.

Scheme 131

The engine has been developed by Volvo.

It is a 6 cylinder transverse in-line engine with a cylinder capacity of 3.2 L for naturally aspirated engines and 3.0 L for turbocharged engines.

After having been relatively unchanged since the introduction 0620, this engine family has been updated on several points. Most modifications have their basis in an effort to achieve lower fuel consumption and thus less environmental impact.

Engine power has increased, at the same time as fuel consumption has decreased.

1. B6304T4: (ULEV2 Ultra Low Emission Vehicle): 300(US)/ 304 hp / 440 Nm
2. B6324S4 (PZEV - Partial Zero Emission Vehicle): 230(US) 233 hp (torque unchanged 300 Nm)
3. B6324S5 (ULEV - Ultra Low Emission Vehicle): 240(US) /243 hp (torque unchanged 320 Nm)

All of these engines meet the emission standards for Euro5.

The engines' idle speed 650 rpm.

The engine is extremely compact. When it was introduced it was the shortest 6-cylinder engine of 3.2 L on the market. Conventional straight 6-cylinder engines are too long to fit between the collision members in the engine compartment. The special design of this engine solves the problem.

The engine has an extremely short drive train, its length is only 625 mm from the front edge of the engine block to the rear edge of the carrier plate.

Great attention has been paid to creating a very rigid engine. Middle part, cylinder block and cylinder head have been structurally optimized to combine low weight with high rigidity.

Even the camshaft cover is structurally optimized.

The engine has double overhead camshafts and 24 valves.

Camshafts, AC-compressor, coolant pump and alternator are driven by an auxiliary unit drive, mounted on the back of the engine.

This placement of the auxiliary unit drive enables new possibilities for creating a good collision-protecting structure around the straight 6-cylinder drive unit. In the latest update of the engine family the servo pump has been replaced by an electrically driven pump (EHPAS).

The entire engine block and the cylinder head is made from aluminum.

The engine has a compact "pent-roof" designed combustion chamber and V-arranged valves. This gives optimal and fast filling and direct flushing via the inlet manifold followed by the combustion chamber (cross-flow) and the exhaust channel.

The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.

The engine's firing order is 1 - 5 - 3 - 6 - 2 - 4. The firings occur every 120 degrees that the crankshaft rotates.

Scheme 132

The cylinder heads and valve covers are made of aluminum.

The seal between the cylinder head and cylinder block occurs using two cylinder head gaskets, one for each cylinder head. The cylinder head gasket is made up of three layers of stainless steel. Two outer and a center which act as a seal around the cylinders. The outer surfaces of the gasket are covered by a rubber layer which functions as a seal. The seal between the other planes is made using liquid gasket.

Scheme 133

The engine has two cylinder banks. The left cylinder bank is slightly offset compared to the right. This allows the use of the vehicle's existing member system and crumple zones.

The engine has double pairs of overhead camshafts - one intake camshaft and one exhaust camshaft in each cylinder head. The camshafts are chain-driven.

Scheme 134

The cylinders are numbered in the order in which they are installed on the crankshaft when seen from the front (from the camshaft's timing gear).

Scheme 135

The engine has four valves per cylinder. The valves are angled at 19 degrees. The valve diameter of the intake valves is 35 mm and the exhaust valve's is 30 mm. The valves are stellite coated. The valve stem diameter for both inlet and exhaust is 5.5 mm.

The combustion chamber is the "Pent roof" type. Together with the V arranged valves this gives optimal and fast filling and direct flushing via the intake channel followed by the combustion chamber (cross-flow) and exhaust channel.

The squish surfaces together with the centrally positioned spark plug provide optimal combustion of the air/fuel mixture, low knock sensitivity and low, stable exhaust emissions.

Scheme 136

The engine's two cylinder heads are in principle mirror images of each other. The cast oil galleries in the cylinder head ensures good oil supply to the camshafts and the mechanical valve lifters.

Scheme 137

The cylinder block is made of cast aluminum. It has a stiff rib structure for better rigidity and thereby better sound and vibration properties.

The cylinder block has eight cast-iron cylinder liners molded into the cylinder block. They cannot be replaced.

The coolant jacket goes halfway down the cylinders to ensure quicker heating and thereby reduce hydrocarbon emissions. Certain sections of the coolant jacket are deeper to reduce the risk of the cylinder deformation.

Scheme 138

The intermediate section is made of aluminum. The crankshaft bearing caps are integrated in the intermediate section. The bearing caps are made of cast iron. The caps are fixed with four screws per cap.

Scheme 139

The oil pan is made of pressed aluminum. It has baffles to prevent the oil moving too much. Because of the exterior dimensions of the engine, the oil pan has a unique shape in order to hold the necessary oil volume. The oil pan is made in two parts for manufacturing reasons.

An electric oil level sensor is located in the pan. There is also a normal oil dipstick for manual checks of the oil volume.

Scheme 140

The pistons are cast and are made of a light metal alloy. The piston mantle is coated with graphite. The first groove is hard anodized to minimize wear.

The piston is equipped with two compression rings and a three piece oil ring.

The connecting rods are forged. The contact surface between the bearing cap and the connecting rod is treated. Guide pins contribute to good alignment. The connecting rod bearings are aluminum bearings. The bearings are lead free.

The piston transfers the compressive force of the ignited fuel/air mixture to the crankshaft via the connecting rod. The piston rings form a seal so that the fuel/air mixture does not force its way down past the piston. The top ring ensures a seal between the piston and the cylinder. The second ring also seals and scrapes away any oil during the downward movement of the piston. The third ring makes sure the oil drains via the drain hole.

The pistons are oil-cooled. This is necessitated by the short distance between the piston head and the top piston ring.

Scheme 141

1. Balancer shaft
2. Crankshaft

The crankshaft is made of carbon steel with a nitride hardened surface. The crankshaft bearings have separate caps, the intermediate section of the cylinder block makes up the lower half of the bearing. The crankshaft has five main bearings where the third also acts as an axial bearing. The main bearings are aluminum bearings.

The crankshaft has offset pins. Two connecting rods are mounted on each crankshaft pin with an internal offset of 30°.

Big-end bearings and axial bearings are lead-free.

Two splined joints are located at the front end of the crankshaft, the inner one drives the oil pump. The timing chain gear is located on the outer joint.

The crankshaft has a three part vibration damper consisting of a hub and two active masses. The hub is located between the inner and outer masses. The crankshaft vibration damper drives the auxiliary belt.

The 60 degree angle between the two cylinder banks means that the engine is equipped with a balancer shaft. This is to give the vibration characteristic which corresponds to a 90 degree V8. The balancer shaft is located in the center of the engine, above the crankshaft. The balancer shaft rotates in the opposite direction to the crankshaft. It is driven by the crankshaft using the same chain that drives the intake camshafts. The balancer shaft rotates at the same speed as the crankshaft.

The balancer shaft is made of spherolitic cast iron (nodular iron).

Scheme 142

The engine has double pairs of overhead camshafts, one intake camshaft and one exhaust camshaft in each cylinder bank. The intake camshafts are located in the middle of the engine while the exhaust camshafts are placed on the outside.

The camshafts are made of cast iron. They are hollow to keep the weight down. Each camshaft pair is mounted in its respective cylinder head with five loose bearing caps per camshaft.

The camshafts work directly on the valve stem via the valve lifters. There is a certain amount of play (valve play) between the valve depressors and the cam lobes. Valve play is adjusted to make up for the longitudinal differences between the valve and cylinder head that occur upon warm-up. The valve depressors are solid and made of steel.

Each camshaft has a CVVT unit. The reset angle is 40.5 crankshaft degrees for the intake camshafts and 42.5 crankshaft degrees for exhaust camshafts.

1. Intake camshafts open -8° to 32, 5° before top dead center (BTDC) and close 60° to 19.5° after the bottom dead center.
2. Exhaust camshafts open 62° to 19.5° before bottom dead center and close -10° to 32.5° after the top dead center (TDC).

Scheme 143

The crankshaft drives the intake camshafts and the balancer shaft using a camshaft chain (1). The camshaft is tensioned by a hydraulic chain tensioner. The tensioner is supplied with oil from the normal lubrication system. The camshaft chain is lubricated with oil via a separate nozzle (2).

The intake camshafts in turn drive the respective exhaust camshafts via their chain (3). This intermediate drive means that the outer exhaust camshafts can have smaller pulley wheels which reduces the size of the engine. The intermediate drive chains each have their own hydraulic tensioner. The tensioner is supplied with oil from the normal lubrication system.

A cover seals the area for the camshaft chain drive.

The system requires no maintenance during the entire life of the engine. Both the chain guide and the chain tensioner have plastic inserts on the treads for quiet operation.

Scheme 144

The lubrication system has a large supply line with a strainer which prevents large contaminants from reaching the oil pump.

The oil pump (1) is driven by the crankshaft. The oil pump is a rotor pump with integrated pressure control valve. The valve opens at approximately 5.0 bar and prevents excessively high pressure which could damage the oil cooler.

The oil cooler is a flat oil cooler. The space for oil and coolant is divided alternately between the plates.

The oil filter (2) is a loose filter element placed in a housing. The overflow valve for a blocked filter is in the cover.

Scheme 145

A specially designed fuel system is used to reduce the height of the engine.

The fuel system is made of stainless steel to ensure reliability. The fuel hose is made of nylon to reduce the weight of the engine.

Scheme 146

An induction system with two modes is used to increase torque at low engine speed. Both the intake manifold and the equalizer tank are made of aluminum.

A moveable damper is located in the common area of the intake pipe. The damper separates the area lengthways into two chambers. The damper is controlled from completely closed to completely open, with no intermediate position. Up to an engine speed of 3200 rpm the damper is closed and the damper is open at higher engine speeds.

By dividing the area into two separate chambers, the area functions as two secondary intake pipes. The primary pipes are the cast pipes which lead to the inlet valves of the respective cylinder's intake valves from the collection volume. A closed damper provides secondary pipes while an open damper gives short secondary pipes.

Engine speeds up to 3200 rpm

The combined length and volume of the pipes is tuned to the piston movement and the valve opening times. The result is that the air pulses in time with the valve opening times. this means that the air is pumped into the cylinders when the inlet valves are open. The system gives a high a volumetric efficiency, that is, fills the cylinders and therefore produces a high torque.

In order not to disturb the pulse frequency the left chamber supplies 1, 4, 6 and 7 while the right chamber supplies cylinders 8, 3, 5 and 2, this is to interact with the firing order 1-8-4-3-6-5-7-2.

Engine speed (RPM) greater than 3200 rpm

At engine speeds greater than 3200 rpm the throttle opens. At these speeds the character of the pulses change character at the same time as a greater volume is required to supply the cylinders with air. The whole area/volume now supplies all cylinders. The common volume and the shape of the pipes is designed to exploit the pulses which occur in this engine speed (rpm) range.

If the damper does not open at 3200 rpm there is marked deterioration in performance from 3200 rpm up to 5000 rpm.

Scheme 147

The throttle body is made of cast aluminum. The position sensor, which is located under the plastic cover, reads the position of the throttle disc and two engine connections that turn the throttle disc. The throttle disc position is determined by how much the driver depresses the accelerator pedal. The throttle body is warmed via engine coolant.

Scheme 148

1. Cylinder block
2. Right cylinder head
3. Electric coolant pump
4. Heat exchanger (passenger compartment)
5. Preheating crankcase ventilation
6. Throttle body
7. Upper cooling hose
8. Bypass pipe
9. To cylinder head
10. Radiator
11. Oil cooler
12. Lower cooling hose
13. Thermostat housing
14. Coolant pump
15. Left cylinder head
16. Expansion tank with level sensor
17. Air bleed circuit

The engine is cooled used reversed cooling, that is, the cylinder head is cooled first. The system gives fast heating and contributes to reducing emissions.

The radiator is made of aluminum to withstand thermal fatigue as the radiator is alternately cooled with cold air and heated with hot coolant. The cooling system is regulated by a mechanical thermostat, which is located in the thermostat housing. The thermostat housing, in turn, is located on the inlet side of the coolant pump, between the radiator and the coolant pump.

The heart of the thermostat is a wax body which expands when energy, in the form of heat, is applied. A jiggle pin is located in the thermostat. Any air in the cooling system can be evacuated from the system using the jiggle pin.

Cold air is sucked through the cooler using an electric engine cooling fan installed on the fan shroud behind the radiator. The engine cooling fan is brushless and has six fixed stages. It is controlled by the engine control module (ECM).

Oil cooler

The oil cooler is round and has an inlet and outlet for oil as well as for coolant. The oil cooler is structured in layers, with alternating layers of coolant and oil flow. Because the oil cooler has very small slits, there is a large pressure drop here.

Scheme 149

1. Generator (GEN)
2. Belt tensioner
3. Servo pump
4. Water pump
5. air conditioning (A/C) compressor.

All auxiliary units, the alternator, servo pump and A/C compressor are directly mounted in the engine block. They are driven by the vibration damper via an auxiliaries belt. This solution gives a compact design.

The coolant pump is also driven by the auxiliaries belt.

The auxiliaries belt has a mechanical belt tensioner.

Scheme 150

HINT: The illustration displays the exhaust system for the XC90.

The exhaust system is made of double-layer sheeting to keep the temperature down. The inner sheet is 1.0 mm thick while the outer is 1.5 mm thick. There is 4-8 mm of space between the sheets.

An exhaust system extends from each cylinder bank. Each side consists of a manifold with close-coupled catalytic converter, pipes, bellows and a rear catalytic converter. Both sides join to form a common pipe after the rear catalytic converter.

The pipes are designed in such a way that the gas flow from the cylinders is not disruptive and there is good flow distribution to the catalytic converters. Bellows in front of the two rear catalytic converters absorb engine movements and compensate for manufacturing and assembly tolerances.

A catalytic converter consists of perforated stones of ceramic or metal (known as substrate). These are coated with a surface enlarger (washcoat) on which the precious metals platinum, palladium and rhodium, the catalysts, are applied.

The catalytic converter has an extra heat shield toward the radiator fan to reduce the temperature.

Four oxygen sensors are used to regulate the engine and monitor the catalytic converter. There is an oxygen sensor upstream and downstream of each close-coupled catalytic converter.

The two banks are almost exactly the same length to ensure good sound. The exhaust system provides the engine's characteristic V8 sound.

Scheme 151

To achieve an even running and characteristic V8 sound, the ignition impulse interval is 90 crankshaft degrees. To reach this in an engine with a 60 degree angle between the cylinder banks, the crankshaft pins for the opposing cylinder pairs are offset by 30 degrees.

Scheme 152

When the left hand piston is at the top, the right hand piston is halfway between the upper and lower turn points. This is because the crankshaft pins are internally offset by 30 degrees.

Scheme 153

When the crankshaft has rotated 90 degrees the right hand piston is at the top and the left hand piston is halfway between the upper and lower turning points.

Scheme 154

When the crankshaft has rotated a further 270 degrees the left hand piston is at the top and the right hand piston is halfway between the upper and lower turning points.

By offsetting the crankshaft pins by 30 degrees in this way the ignition impulses will occur every 90th crankshaft degree.

Scheme 155

The Example shows the principle for cylinder 1 and 2. With the firing order 1-8-4-3-6-5-7-2 the following occurs

1. Cylinder 1 fires.
2. The crankshaft then rotates 360°+270°=630° until cylinder 2 fires.
3. The next ignition impulse, now again for cylinder 1, occurs when the crankshaft has rotated a further 90 degrees.

Scheme 156

1. Cylinder head
2. Cylinder block
3. Intermediate section
4. Oil sump
5. Crankshaft
6. Oil filter
7. Camshafts

Oil is led from the oil sump via a suction nozzle to the oil pump, which is located on the crankshaft. The oil pump suction function is facilitated by a purge valve that eliminates any air from the system.

The oil is pumped on to the oil cooler system and then on to the oil filter. The oil is led from the filter through a cast oil duct in the intermediate section to the main bearings. The oil is distributed to the big-end bearings via drilled channels in the crankshaft.

The camshafts receive their oil supply via drilled channels in the cylinder block. The channels continue up through the cylinder heads where they open out on the underside of the lower half of the cylinder head. There is a cross channel in the channels to the cylinder heads which leads oil to the pistons. From here the oil is moved further via the oil channels to the intake camshaft bearings and valve lifters.

The exhaust camshaft bearings are supplied via two cast cross channels at the front of the upper halves. The oil is led via drains in the block from the cylinder heads and from the crankshaft bearings back to the oil pan.

Scheme 157

The system is pressure controlled and completely enclosed.

Crankcase gases flow up to both the valve covers. There is a hose connecting the valve covers. A labyrinth system of plates is installed in the valve covers. The oil in the gases condenses on the plates and drains back to the oil pan.

The ventilation is pressure controlled to retain stable pressure in the crankcase. A pressure regulator is installed on the rear edge of the right valve cover. The gases which are evacuated are led from the regulator through a hose to a connection on the inlet pipe. Coolant is circulated around the connection to prevent freezing.

The pressure in the crankcase is approximately - 0.03 bar.

Scheme 158

The combustion of fuel in the vehicle engine produces both mechanical motion and excess energy. The excess energy takes the form of heat that is led away from the engine via

1. exhaust gases
2. convection to the air in the engine compartment
3. transfer to the coolant in the cooling system
4. the engine oil.

The thermostat (1) regulates the amount of coolant to the engine. The wax body in the thermostat expands when subjected to heat.

The coolant is pumped by the coolant pump (2) to the inlets (6) for the cylinder heads (3). The coolant flows forward through the relevant cylinder head and on through the cylinder banks back to the common outlet (4). After passing the engine the coolant flows by

1. Closed thermostat through the bypass pipe (5) back to the coolant pump without cooling off.
2. Open thermostat through the radiator (7) to the coolant pump. The coolant also flows through the bypass pipe back to the coolant pump.

EXHAUST SYSTEM

HINT: The illustration displays the exhaust system for the XC90.

The three-way catalytic converters clean by oxidizing carbon monoxide (CO) and hydrocarbons (HC) to water and carbon dioxide (CO 2 ). Nitrous oxides (NO x ) are reduced to nitrogen and water. The catalytic converter transforms over 98 percent of these substances during normal operation. Lead contaminates in the fuel can damage the catalytic converter, quickly rendering it inoperable.

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).

Scheme 159

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).

The signal from the engine speed (RPM) sensor is also used to check the engine for misfires. For further information, see: MISFIRE DIAGNOSTIC

The impulse sensor is located on the engine's flywheel side, pointing forward. The sensor is inductive with permanent magnet. When the flywheel/drive flange plate passes the impulse sensor, an alternating voltage is induced in the sensor. The generated voltage and frequency increase when the engine speed increases.

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 speed sensor can be diagnosed by the engine control module (ECM) and the sensor signal (engine speed) can be read out.

Scheme 160

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 is divided into a number of flanks (segments) per camshaft revolution. A pulse wheel on the camshaft consisting of teeth (the teeth are positioned by each flank) is used by the camshaft position sensor (CMP) to detect the flanks and the position of the camshaft.

In the event of misfire or engine knock, the control module is able to determine which cylinder is misfiring or knocking using the camshaft position (CMP) sensor's signal.

Data about the camshaft position is used during camshaft control (CVVT). See: 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 and 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.

There is camshaft position (CMP) sensor for each camshaft.

The camshaft sensors are located by the camshafts on the engine's left side, closest to the flywheel.

The engine control module (ECM) can diagnose the camshaft position (CMP) sensors.

Scheme 161

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 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 thereby which cylinder is knocking.

The knock sensors (KS) are located on the cylinder block under the intake manifold.

The engine control module (ECM) can diagnose the knock sensors (KS).

Scheme 162

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, 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 temperature sensor is located by the thermostat under the intake manifold.

The engine temperature sensor can be diagnosed by the engine control module (ECM) and the sensor value can be read out.

Scheme 163

Overview

The mass air flow (MAF) sensor is a combined sensor and contains two sensors in the same component

1. Mass air flow (MAF) sensor
2. intake air temperature (IAT) sensor.

The mass air flow sensor is located by the air filter housing.

Mass air flow (MAF) 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 gearbox control module (TCM) also uses this data for its gear shift calculations. This data is transmitted to the gearbox 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 analog and varies between approximately between 0.5 - 4.5 V. Low air flow (low mass) results in low voltage, high air flow (high mass) gives high voltage.

The mass air flow (MAF) sensor can be diagnosed by the engine control module (ECM) and the sensor signal can be read off.

Intake air temperature (IAT) 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 intake air temperature. 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 temperature sensor can be diagnosed by the engine control module (ECM) and the sensor signal can be read off.

HEATED OXYGEN SENSORS (HO2S)

Front heated oxygen sensor (HO2S)

Scheme 164

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 before the three-way catalytic converter (TWC). This is so that the engine control module (ECM) can continually check the combustion so that lambda=1 is achieved. lambda=1 is the ideal fuel-air ratio, with 14.7 kg air per 1 kg fuel.

The heated oxygen sensor uses current regulation 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 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.

There are two front heated oxygen sensors; one for bank 1 and one for bank 2.

The heated oxygen sensors (HO2S) are diagnosed by the engine control module (ECM) and the signals from them can be read off. For further information, see: HEATED OXYGEN SENSOR (HO2S) DIAGNOSTIC

The control module can be used to read off the calculated lambda value from the heated oxygen sensor (HO2S) signal.

Rear heated oxygen sensor (HO2S)

Scheme 165

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 Rear heated oxygen sensors (HO2S) are 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. Rear heated oxygen sensors (HO2S) have no direct effect on regulation of the fuel/air mixture. However the Engine Control Module (ECM) uses the signal to optimize the signal from front heated oxygen sensors (HO2S). For further 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).

There are two rear heated oxygen sensors; one for bank 1 and one for bank 2.

The heated oxygen sensors (HO2S) can be diagnosed by the engine control module (ECM), and signals from them can be read off

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 sensor's heating coil consists of a PTC-resistor. The heating coil is supplied with voltage from the system relay and is grounded internally in the Engine control module (ECM).

When the control module grounds the connection, a current will pass through the PTC-resistor. When the heated oxygen sensor is cold, the resistance in the PTC-resistor is low and a high current will pass through the circuit. To avoid condensation damage to the heated oxygen sensor the current is pulsed from the Engine control module (ECM) in the beginning. Depending on the temperature, consideration is given to dew point and, as the temperature increases in the PTC-resistor, the resistance increases in the resistor, the current is reduced and transfers gradually to non-pulsing current.

The heating period for the front heated oxygen sensor is short, approx. 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 166

The purpose of the brake light switch is to provide the engine control module (ECM) with information indicating whether the brake pedal is depressed.

When the brake pedal is pressed down, a signal is sent to the Engine control module (ECM), which turns off the cruise control (if it is activated). The brake pedal position sensor also handles the function for switching off 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 stop lamp switch can be diagnosed by the engine control module (ECM) and its status (depressed or not) can be read off.

The brake light switch is on the pedal box by the brake pedal.

Scheme 167

The air conditioning (A/C) pressure sensor detects the pressure in the high-pressure side of the air conditioning (A/C) system. See: 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 the diagnostic tool.

Scheme 168

The function of the accelerator pedal position sensor is to provide the engine control module (ECM) and central electronic module (CEM) information on the position of the accelerator pedal. The engine control module (ECM) uses this data to deploy the shutter in the throttle unit to the correct angle.

The accelerator pedal position sensor consists of a plastic housing with two potentiometers, and an Analog/Digital converter. The potentiometers are connected to a common shaft which is affected by the position of the accelerator pedal.

The accelerator pedal (AP) position sensor transmits an analog and a pulse width modulated (PWM-signal to the engine control module (ECM). These signals indicate the position of the accelerator pedal (AP). The digital signal is generated by the sensors Analog/Digital converter.

The analog and digital signals are used at the same time by the engine control module (ECM) to regulate the throttle shutter angle.

The power supply to the two potentiometers is different. The analog potentiometer is supplied with 5 V via the engine control module (ECM). The digital potentiometer is supplied with 12 V via the system relay and is grounded in the car body.

The digital signal is used together with the analog signal for diagnostics of the accelerator pedal position sensor.

Accelerator pedal (AP) position sensor's signals can be read off.

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.

Scheme 169

The outside temperature sensor detects the temperature in the surrounding air. The signal is used by the engine control module (ECM) as a substitute value in the event of a fault in certain components or functions and to control certain diagnostic functions.

The sensor is a negative temperature coefficient (NTC) type which is supplied with power from the control module (signal). The resistance in the sensor changes with the outside temperature. This alters the signal 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 outside temperature sensor is positioned in the left door mirror.

The outside temperature sensor can be diagnosed by the engine control module (ECM) and the sensor value can be read off.

Scheme 170

The function of the engine coolant level sensor is to alert the driver if the engine coolant level in the expansion tank is too low.

The sensor is a magnetic reed switch, which is enclosed in a pipe on the bottom of the expansion tank. Around the pipe, on the inside of the expansion tank is a float. This float contains a magnet. When the engine coolant level is above minimum, the float is too high in the tank to affect the switch. However if the engine coolant level falls below the minimum level, the magnetic field acts on the switch.

The sensor is supplied with voltage (signal) from the engine control module (ECM) and grounded in the body. When the engine coolant level in the expansion tank is over a certain level the circuit closes, which produces a low signal. When the engine coolant level is below a certain level the circuit is opened by the engine coolant level sensor, which produces a high signal. When the engine control module (ECM) detects a high signal the information about low engine coolant level is transmitted via the Controller area network (CAN) to the driver information module (DIM), which warns the driver.

Note. There are no functions controlled by the engine which are directly connected to the low coolant level warning lamp. The Engine Control Module (ECM) only transfers the signal which is used by the Driver Information Module (DIM).

The engine control module (ECM) cannot diagnose the engine coolant level sensor.

Scheme 171

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.

Manifold absolute pressure (MAP) sensor, intake is located on the lower part of the intake manifold at the electronic throttle module.

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 to the control module. Low pressure results in low voltage, high pressure gives high voltage.

The pressure sensor can be diagnosed by the engine control module (ECM) and the sensor signal can be read off.

Scheme 172

Overview

The fuel pressure, fuel temperature sensor is combined and consists 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 located on the fuel rail's end.

The fuel pressure-/fuel temperature sensor can be diagnosed by the engine control module (ECM) and its signals (pressure and temperature) can be read off.

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 to the engine control module (ECM). Low pressure results in low voltage, high pressure gives 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.

Note. The absolute pressure is displayed when using parameter read outs 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 volume of the fuel.

Scheme 173

The function of the oil level sensor is to provide the engine control module (ECM) with information regarding the level of engine oil in the oil sump.

The sensor consists of

1. a terminal with three pins
2. integrated electronics
3. 2 capacitive gauge elements
4. a PTC resistor.

The oil level sensor is supplied with 5 V by the engine control module (ECM). The oil level sensor generates a pulse width modulated (PWM) signal for the engine control module (ECM).

The oil level sensor can be diagnosed by the engine control module (ECM).

The pulse-width modulated (PWM) signal from the oil level sensor can be read using parameter readout.

Scheme 174

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 175

The function of the injectors is to spray fuel into the cylinders in the correct spray patterns. This happens sequentially.

The injectors are located along the intake pipe.

The engine control module (ECM) controls the injectors by grounding the valves in pulses.

The injectors can be diagnosed by the engine control module (ECM) and can be activated.

Scheme 176

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. The signal reconnects to the engine control module (ECM) so that diagnostics can be carried out.

Each ignition coil has an integrated power stage.

The ignition coils are in the sparkplug wells above each spark plug.

The control module checks the ignition coils' function using one separate diagnostic lead.

Scheme 177

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)

An oil filter is mounted at the intake channel for the valves to prevent oil contaminants from affecting the function of the reset valves.

The system relay supplies the reset valve with voltage via a fuse. The valve is grounded (control stage) internally 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 allows the angle position to be changed precisely and steplessly.

The engine control module (ECM) can diagnose the camshaft reset valve.

The valve is located on the cylinder head above the camshaft. There is a valve for intake camshaft.

There is no valve for the exhaust camshaft.

Scheme 178

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 electromagnetic valve and 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 evaporative emission system (EVAP) valve can be diagnosed by the engine control module (ECM) and can be activated.

The EVAP-valve is located by the intake manifold (by the electronic throttle module) on the front of the engine.

Scheme 179

The function of the leak diagnostic unit is to pressurize the fuel tank system during leak diagnostics and to open the fuel tank system to the surrounding air during evaporative emissions control.

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).

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). Operation depends on whether the diagnostic phase is checking for leakage or checking the function of the diagnostic system. The engine control module (ECM) gauges the power consumption of the pump during pressurization. The power consumption corresponds to a certain pressure in the fuel tank system. See also: LEAK DIAGNOSTIC UNIT

The engine control module (ECM) can diagnose the leak diagnostic unit.

The valve in the leak diagnostic unit can be activated and the power consumption of the pump can be read off.

The leak diagnostic unit is at the upper front edge of the fuel tank.

Scheme 180

The air conditioning (A/C) compressor transports refrigerant, which is necessary for air conditioning (A/C) operation. It is an axial piston compressor with variable displacement. I. E. The compressor has adjustable cylinder displacement which is controlled by a check valve (solenoid). The valve, which is underneath the compressor, can be replaced.

The A/C compressor is mounted on the cylinder block and is driven by the engine's crankshaft via the auxiliaries belt.

Scheme 181

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 / opening 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 CAN network from the climate control module (CCM) to activate the relay and start the compressor.

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/fusebox in the engine compartment.

Scheme 182

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) consists of two fans and two control modules. The control modules are controlled by the same signal from the engine control module (ECM).

HINT: For different reasons, there are variants where the engine cooling fan consists of two fans and one control module.

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 modules. The control modules then activate the fans at different speeds. The speed is determined by the engine control module (ECM), depending on the coolant temperature 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) is located behind the radiator and its control module is grounded and powered with battery voltage via a fuse.

There are diagnostics for the engine cooling fan (FC). The engine cooling fan (FC) transmits a diagnostic signal to the engine control module (ECM).

Scheme 183

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 can be read off.

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.

Scheme 184

The fuel pump control module is called PEM (Pump Electronic Module). It 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 off using the diagnostic tool.

The fuel pump control module is on the outside on the right-hand side of the fuel tank.

Scheme 185

1. Primary actuator with throttle (upper)
2. Secondary actuator with throttle (lower)

The function of the actuators is to vary the length of the intake manifold, via throttles installed in the intake manifold.

The actuators are supplied with voltage from the system relay via fuse and ground (control) internally in the engine control module (ECM).

see VARIABLE INTAKE SYSTEM

The actuators for variable intake can be diagnosed by the engine control module (ECM).

The actuators are bolted directly to the intake manifold.

Scheme 186

The function of the solenoid is to control (trigger) oil pressure to the hydraulic valve depressors.

The solenoid is supplied with voltage from the system relay via fuse and ground (control) internally in the engine control module (ECM).

The system has two solenoids that each supplies a number of cylinders.

The solenoids are located on each side of the engine between the camshafts.

The solenoids can be diagnosed by the Engine control module (ECM).

see VARIABLE CAMSHAFT PROFILE (CPS)

Scheme 187

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.

If Readiness 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.

Scheme 188

The electronic throttle unit, using the PWM control signal from the engine control module (ECM), regulates the amount of air for engine combustion. This is done using an electronically controlled shutter.

The aluminum electronic throttle unit consists of a round throttle disc on a spindle. The spindle is driven by a DC motor (damper motor), gear wheel and two springs; one for opening and one for return.

By changing the polarity of the power supply, the DC motor can be run in both directions. At one of the limit positions the throttle disc is closed so that minimal air can pass the throttle unit. In the other limit position, the throttle disc is parallel to the air flow. This provides maximum airflow through the electronic throttle unit.

Two permanent magnets in the gear sector on the throttle spindle are used to check the position of the throttle disc. The permanent magnets affect two throttle position (TP) Hall sensors in the cover. The analog signals from the two sensors are transmitted to the engine control module (ECM). The signals are offset. The engine control module (ECM) compares these signals with the stored desired values to check if they are plausible.

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

Electronic throttle unit.

Scheme 189

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. Canister purge (CP) 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; 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. the engine coolant temperature (ECT) sensor atmospheric pressure sensor outside temperature sensor.
2. The engine is switched off until the engine coolant temperature (ECT) has fallen to a few degrees above the outside temperature, then engine running for at least 10 minutes.
3. Ignition off
4. Vehicle speed 0 km/h
5. Engine coolant temperature (ECT) -5 °C or higher.
6. Maximum altitude of 2500 meters above sea level
7. Outside temperature between -5 and +35 °C.
8. Fuel volume in the tank less than 85%. The engine control module (ECM) ignores these parameters if a diagnostic trouble code (DTC) is stored for the fuel level sensor and the fuel volume cannot be determined.
9. Battery voltage between 11.0-15.0 V. The voltage must be stable.
10. EVAP canister purge valve closed
11. Low volume in the canister.
12. Fuel tank filler cap locked. Tip. Locking occurs when the vehicle speed exceeds approximately 20 km/h.

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
2. function test
3. Leak diagnostic

Scheme 190

Reference phase (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 for leakage. Reference phase (1-2) for leakage that is 0.5 mm is carried out by the pump in the leak diagnostic unit pumping 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 compared 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 (1-2), or if the value for pump power consumption varies too much during reference phase (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 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 (3). 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 191

Leak diagnostic, major leak (leakage greater than 1.0 mm)

The diagnostic for "major leaks" is carried out each 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). A diagnostic trouble code (DTC) for a major leak is stored if the measured value does not reach the calculated desired value within a certain time (the time is determined by the fuel level in the tank).

Leak diagnostic, minor leak (leakage greater than 0.5 mm but less than 1.0 mm)

The diagnostic for minor leaks is run every other time that 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 (5-6). After a certain amount of time (the time varies depending on the fuel level in the tank), the engine control module (ECM) checks the fuel tank system for leaks. This is determined from calculations based on

1. time
2. the measured reference current consumption of the pump (A)
3. the measured power consumption of the pump when the assessment is made
4. the shape and character of the current curve during pressurization.

A diagnostic trouble code (DTC) is stored if a minor leak is detected.

New software can be downloaded into the engine control module (ECM). 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 Engine control module (ECM) is located on the air filter box, under a plastic cover.

The engine control module (ECM) contains a unique code for each car for the immobilizer. The central electronic module (CEM) checks this code at engine start up. The engine will not start if the central electronic module (CEM) detects an incorrect code for the immobilizer. This means that the engine control module (ECM) cannot be switched from vehicle to vehicle.

The engine control module (ECM) must first be "unlocked" using a unique PIN for each car before it can be programmed with a code for the immobilizer. When the PIN has been approved by the engine control module (ECM), the code for the immobilizer can be programmed.

The PIN and the code for the immobilizer are obtained from the Volvo central database and sent out with the software package when software for downloading has been ordered.

All new engine control modules (ECM) have the same PIN which is preprogrammed by the control module supplier. When the engine control module (ECM) has been programmed successfully the original PIN for the car will be programmed in the engine control module (ECM) memory and will replace the preprogrammed PIN code.

Scheme 192

The starter motor (6/25) is supplied with power via the starter motor relay (2/35), the starter motor 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 (U bat ) from the ignition switch (3/1) is transmitted to the engine control module (ECM) via the central electronic module (CEM) (4/56). 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 solenoid by grounding and powering the coil for the starter motor relay.
4. The relay closes the circuit between the starter motor solenoid and the fuse in the relay/fuse box in the engine compartment, activating the starter motor.
5. The engine control module (ECM) activates the starter motor until the engine starts (the engine speed (rpm) exceeds a certain value)

Auto start

If the ignition key returns to ignition position (position II) before the engine is started, the starter motor continues to run. The starter motor runs until the engine is started or until a certain time has elapsed. The engine temperature dictates the running time of the starter motor

1. 0 °C or higher, approximately 3 seconds
2. less than 0 °C, up to approximately 5 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).

Scheme 193

Only the intake camshaft can be controlled by the Engine control module (ECM) via a reset valve.

The intake camshaft is located in the engine's leading edge (in the travel direction) and the exhaust camshaft in the trailing edge (towards the passenger compartment).

The camshafts are driven by the crankshaft via a gear housing located on the engine's top side.

When each camshaft is adjusted in the factory, its position is aligned with the crankshaft's position. The camshaft's position at alignment against the crankshaft is called the camshaft's 0-position (basic setting).

At camshaft control (CVVT), the camshaft's 0-position is displaced so that the camshaft's angle position is changed. Thus, opening and closing of the exhaust and inlet valves changes relative to the crankshaft.

By controlling the camshaft's angle position, the engine's performance can be increased, idle quality can be improved, and emissions can be reduced.

The engine control module (ECM) detects the position of the camshafts by comparing the signals from the engine speed (RPM) sensor (1) (crankshaft position) and the camshaft position (CMP) sensors (2) (camshaft positions). The engine control module (ECM) then controls the angle of the camshaft by controlling the oil flow to the CVVT unit using the reset valve camshaft (3).

There are diagnostics for this function. See also: CAMSHAFT DIAGNOSTICS (CVVT)

Controlling, reset valve camshaft

Scheme 194

1. Oil filter reset valve camshaft.
2. Oil channel (pressure, inlet).
3. Channel connected with CVVT-unit's chamber (triggering).
4. Channel connected with CVVT-unit's chamber (re-triggering).

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 (CVVT)

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 CVVT-unit's rotor. The rotor (and thus, the camshaft) can rotate in relation to the timing belt pulley by the oil pressure building up on one or the other side of the rotor's vanes in the CVVT-unit.

Control occurs according to the following during deployment/return of the camshaft.

Scheme 195

A: Inlet camshaft

1. Oil pressure from the lubrication system (1) of the engine.
2. The oil passes the filter for the camshaft reset valve (2) and then on to the reset valve (3).
3. The engine control module (ECM) controls the oil flow to one of the CVVT unit chambers (4) depending on whether it is to be deployed/returned by the camshaft.

The reset valve is controlled by the engine control module (ECM) by high frequency, switching for deployment and return. This results in rapid and precise control. The inlet camshaft can be triggered up to approx. 40 crankshaft degrees.

Scheme 196

The engine control module (ECM) (4/46) regulates the charge voltage of the alternator (GEN) (6/26) (via LIN communication) when requested by the central electronic module (CEM) (4/56) (via CAN communication).

The engine control module (ECM) can change the requested charging voltage from the central electronic module (CEM) in order to adapt it to certain operating conditions such as starting, idling or high engine loads.

The value of requested charge voltage from the engine control module (ECM) and the charge current of the generator can be read off.

The alternator control module (ACM) (6/26) transmits information to the engine control module (ECM) regarding any faults). The diagnostic trouble codes (DTCs) are stored in the engine control module (ECM) in the event of a fault. In the event of certain faults, information about these faults is also transmitted to the central electronic module (CEM).

Scheme 197

General

Today's modern car engines often utilize systems with variable length of the intake manifolds.

In older engines with fixed lengths, the length had to be adapted to a certain specific engine speed range.

Today's system gives greater flexibility as well as additional torque without any costs in the form of, e. g., fuel consumption or emissions.

In the variable intake system, there are two actuators with associated throttles to change the length of the intake manifolds. These are

1. Actuator variable intake manifold, upper (6/139)
2. Actuator variable intake manifold, lower (6/140)

The primary throttle is activated at engine speed over approx. 4800 rpm and the secondary throttle is activated between approx. 3800 rpm and 4800 rpm (applies at + 20 °C).

Different throttle combinations

1. Position 1: Both throttles are closed at engine speeds lower than approx. 3800 rpm.
2. Position 2: The secondary throttle opens at approx. 3800 rpm and this shortens the length some more.
3. Position 3: Both throttles are fully open to minimize the length at higher engine speeds (over 4800 rpm).

The valve for variable intake is controlled by the engine control module (ECM) (4/46).

The actuators for variable intake function can be activated and the function for variable intake can be diagnosed by the engine control module (ECM).

Scheme 198

1. High lift
2. Low lift

To maintain low fuel consumption at different loads and engine speeds, there is a system for variable camshaft profile (CPS, Cam Profile Shifting) that can vary the duration and lift height of the valves on the intake camshaft.

Duration = part of the rotating camshaft's revolution that the camshaft acts on the valve.

The system is made up of hydraulic valve depressors where the Engine control module (ECM), via oil channels, can set the valve depressors in two positions, one low position and one high position.

At start and at low temperatures (oil temperature below +40 °C, the system is pressureless and thus in its low position (spring loaded).

To minimize stresses the Engine control module (ECM) pressurizes the depressors that are not loaded at the moment. For this, two cam profile solenoids are needed.

Cam profile solenoid 1 (CPS1) supplies cylinder 1, 2, and 4, and cam profile solenoid 2 (CPS2) supplies cylinder 3, 5, and 6 with pressurized oil.

Scheme 199

General

The following components are used for oil monitoring

1. oil level sensor (7/35)
2. engine control module (ECM) (4/46)
3. driver information module (DIM) (5/1).

The oil level sensor, via the driver information module (DIM), is used to inform the driver if oil filling is required.

Detecting the oil level

The integrated electronics of the sensor calculates the oil level using the measured value for the oil temperature.

For the correct oil level to be calculated, temporary oil level changes in the oil trough must also be included in the calculation, which can occur when driving on hills, around bends or similar for example. The engine control module (ECM) makes these calculations using the oil level sensor signal and a number of other parameters, for example, vehicle speed signal and load signal.

Scheme 200

The following components are used when controlling the cruise control

1. engine control module (ECM) (4/46)
2. steering wheel module (SWM) (3/254)
3. control unit cruise control (3/4)
4. central electronic module (CEM) (4/56)
5. brake control module (BCM) (4/16) (brake pedal position, speed signal)
6. driver information module (DIM) (5/1) (cruise control light)
7. transmission control module (TCM) (4/28)
8. electronic throttle unit (6/120)
9. brake light switch (3/9).

To activate cruise control, the function must be switched on using the "CRUISE" button. Then a light is activated 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 CAN network to the central electronic module (CEM) which then transmits the message on via the high speed side of the CAN network 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 vehicle speed increases as normal and then resumes 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, for example, if the driver depresses the brake pedal, the previous speed can be resumed by pressing the "RESUME" button.

The cruise control cannot be activated below a certain speed.

Cruise control is switched off

1. when the driver depresses the 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" position is transmitted on the controller area network (CAN)
5. if the speed deviates too much from the set value
6. when the control system detects a fault that prevents activation.

Scheme 201

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 202

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 203

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 204

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 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 injection period calculated in the base program is limited.

The short-term fuel trim can be read off.

Adaptive functions

Scheme 205

Certain factors, for example, tolerance deviations on certain components such as mass air flow (MAF) sensor and injectors, air leakage on the intake side, fuel pressure etc. affect the fuel / air mix. In order to compensate for this, the engine control module (ECM) has adaptive (self learning) functions. When the engine is new the short term fuel trim varies cyclically around a nominal central line (A) 1.00, with, for example, a ±5% change of injection time when fuel trim is in operation.

If there is air leakage for example, the short-term fuel trim will quickly 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).

The adaptive functions are split into various operational ranges based on the load and speed of the engine.

The different adaption ranges can be read off.

The adaptive adjustments of injection time are continuously stored in the engine control module (ECM). This means that, at different operating ratios, the correct mixture ratio is achieved before the heated oxygen sensor (HO2S) reaches operating temperature.

The diagnostic trouble code (DTC) is stored in the engine control module (ECM) if any adaption value is too high or too low.

INDIVIDUAL CYLINDER FUEL TRIM (-2009)

General

The Engine control module (ECM) controls the fuel according to the description in Fuel trim above, but has another refined system for improving exhaust values, namely individual cylinder fuel trim.

In short, this means that the Engine control module (ECM) can detect the fuel/air mixture composition for each individual (6 cylinders).

To achieve this requires, among others, refined heated oxygen sensors that are very sensitive to the oxygen content in the exhausts.

Should problems occur, which would mean that the sensors, "lose" their extra sensitivity, the Engine control module (ECM) will return to traditional fuel trim.

This will not force the vehicle outside any limit values for exhausts, since this is more than enough to give "clean" exhausts.

Scheme 206

General

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 650kPa) 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) with integrated atmospheric pressure sensor
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 using the signal from the atmospheric pressure sensor and fuel pressure sensor. This particularly 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) calculates the desired fuel pressure. A signal is then transmitted to the fuel pump control module indicating the desired fuel pressure. Serial communication between the engine control module (ECM) and the fuel pump control module is used to carry the signal. 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 reached, and if necessary a signal is transmitted to the fuel pump control module requesting that the fuel pressure is adjusted.

The engine control module (ECM) attempts too obtain a constant fuel pressure (approximately 380kPa relative to atmospheric pressure with the engine running).

By-pass valve

When the injectors close when the pressure is too great (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 650 kPa.

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 207

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 cylinder knocks, then certain types of vibrations in the engine block. These vibrations are transmitted to the knock sensors (7/23-24), which are bolted in the engine block.

One knock sensor detects knock on cylinders 1, 2, 3. The other knock sensor detects knock on cylinders 4, 5, and 6.

The mechanical stress generated in the knock sensors' piezo-electric materials result in generation of a voltage. The Engine control module (ECM) (4/46) can then, using the camshaft sensors (7/172-173) and the impulse sensor (7/25), decide which cylinder is knocking.

The knock sensors (KS) also interpret a proportion of 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 sensors (KS) detect 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 208

The following components are used for ignition control

1. engine speed (RPM) sensor (7/25)
2. Camshaft sensor (7/172-173)
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) (7/23-24)
7. transmission control module (TCM) (4/28)
8. spark plugs with ignition coils (20/3-8).

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 sensors (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) is going to shift, sometimes it sends a request for torque limitation to the Engine control module (ECM). Which then lowers the ignition momentarily to reduce the torque and thus give smoother shifting and reduced load on the transmission.

Lowering of ignition can be done in several levels, where the levels depend 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).

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 209

The air conditioning (A/C) compressor is controlled by the engine control module (ECM) (4/46) on request from the climate control module (CCM) (4/6) 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/fusebox in the engine compartment and the clutch for the air conditioning (A/C) compressor (8/3). The air conditioning (A/C) compressor which has a variable cylinder displacement is always running during normal driving. Displacement in the compressor is regulated by a solenoid which is controlled by the engine control module (ECM).

The engine control module (ECM) controls the solenoid (displacement) from the driver's and vehicle's various driving characteristics. On Startup of the engine, pulling off and at acceleration etc, displacement is controlled so that the A/C compressor has the least possible effect on the engine torque. The climate control module (CCM) controls all functions in the climate control system that are related to the vehicle's interface for driver and passenger. I. E. the climate control system buttons on the dashboard environment panel.

The climate control module (CCM) transmits information to the engine control module (ECM), which determines what must be prioritized. For example, the air conditioning (A/C) compressor in certain extreme cases is switched off completely, regardless of the climate control module (CCM) request. This is to prevent negative engine performance and to protect the air conditioning (A/C) system. As well as the information from the climate control module (CCM), the engine control module (ECM) controls the air conditioning (A/C) compressor based on the information from

1. Air conditioning (A/C) pressure sensor (high pressure side) (7/8)
2. the throttle position (TP) sensor (6/120)
3. the engine coolant temperature (ECT) sensor (7/16).

Scheme 210

To ensure that the correct throttle angle is reached, the engine control module (ECM) (4/46) controls the throttle shutter in the throttle unit (6/120), mainly using the signal from

1. Accelerator pedal (AP) position sensor (7/51)
2. the throttle position (TP) sensor on the electronic throttle unit.

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
3. engine coolant temperature (ECT)
4. mass air flow through the intake manifold
5. manifold absolute pressure (MAP) in the intake manifold.

The position of the throttle is measured by two potentiometers, in the throttle position (TP) sensor, which are on the throttle unit. These are connected, so that potentiometer 1 produces a higher voltage as the throttle angle increases, while potentiometer 2 does the opposite.

In a combustion engine, the difference between the minimum and maximum airflow is considerable. The smaller air flows need more thorough regulation, so the potentiometer signal from potentiometer 1 is amplified approximately 4 times in the engine control module (ECM) before it reaches the AC/DC 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 and to deploy the damper motor to the correct position. In general the amplified signal is primarily used for small throttle angles (small air flows), which are desirable when a high degree of accuracy is required, for idle air trim for example.

Because the signal is amplified, it reaches its maximum value as early as approximately a quarter of maximum deployment.

The engine control module (ECM) primarily uses the signal from potentiometer 1 as a measurement of throttle opening. The signal from potentiometer 2 is mainly to check that potentiometer 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 throttle unit" below.

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 potentiometers.

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 there is a fault in the engine control module (ECM) so that the throttle unit cannot be operated or powered, the springs in the throttle unit will turn the throttle disc to the limp home position (return position). This return position gives a throttle angle large enough to allow the car to be driven to a workshop, although with considerably reduced driveability.

Throttle angle

The throttle angle is usually gauged by potentiometer 1. For small angles the amplified signal is used to obtain a clearer signal. The engine control module (ECM) also monitors the throttle unit signals from the potentiometers to check that they are plausible, that they are within the minimum and maximum limits and that the signals correspond to the same throttle angle. If there is a difference in the signals, a fictitious throttle signal is calculated from the load signal, the engine speed (rpm) and the prevailing conditions, particularly pressure and temperature.

The potentiometer whose signal is closest to the calculated throttle angle will then be assumed to be correct. The other potentiometer is then classified as not functioning and a diagnostic trouble code (DTC) is generated. The system then constantly monitors the throttle angle of the remaining potentiometer in comparison to the calculated throttle angle. If there is a difference between these values, the engine control module (ECM) will not rely on any of the throttle unit potentiometers. The power stage in the throttle unit is then disengaged, and the throttle switches to limp home mode.

Adaptation of the throttle unit

In ignition position II, the engine control module (ECM) carries out adaptation of the electronic throttle unit. Adaptation is carried out by the throttle disc being mechanically controlled to the closed position and the current throttle position being read off. If previous adaptation values are missing in the engine control module (ECM), for example, if the control module has not been powered, the current throttle angle is stored as the adaptation value. If, in addition, there is a previously stored value, the average value of the previous one and the current throttle angle is stored as the new adaptation value.

HINT: When replacing the electronic throttle unit, the engine control module (ECM) must therefore always be switched off.

Scheme 211

The engine control module (ECM) controls, amongst others, the following functions

1. injectors
2. ignition
3. camshafts (CVVT)
4. Evaporative emission system (EVAP) valve
5. throttle angle
6. engine cooling fan (FC)
7. air conditioning (A/C) compressor.
8. fuel pump
9. Variable intake system
10. variable camshaft profile.

The engine control module (ECM) is supplied with battery voltage (U bat ) 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.

Functions which require battery power (U bat ) 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 in the engine control module (ECM).

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 interprets the signals from the different sensors and how the components and functions should be controlled.

The engine control module (ECM) has several self-learning (adaptive) functions. It continually adapts ongoing calculations to changing circumstances (such as 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 located on the air filter box, under a plastic cover.

The engine control module (ECM) communicates with other control modules using controller area network (CAN) communication or LIN 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 engine control module (ECM).

The substitute value allows the vehicle to be driven and for the emissions to be kept at a reasonable level even though vital functions or 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 internal memory of the engine control module (ECM). The information can be read off 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, LIN and CAN communication. The illustration below gives the same information as the Volvo component designations.

Scheme 212

Scheme 213

see DESIGN

see DOWNLOADING SOFTWARE AND REPLACING THE CONTROL MODULE

see FUNCTION

Front heated oxygen sensor (HO2S)

Scheme 214

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 before the three-way catalytic converter (TWC). This is so that the engine control module (ECM) can continually check the combustion so that lambda=1 is achieved. 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 changing the oxygen content in the exhaust gases. 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.

There are two front heated oxygen sensors; one for bank 1 and one for bank 2.

Bank 1 (front cylinder row); cylinders 1, 3, 5 and 7.

Bank 2 (rear cylinder row, closest to the passenger compartment); cylinders 2, 4, 6 and 8.

The heated oxygen sensors (HO2S) can be diagnosed by the engine control module (ECM), and signals from them can be read off. For further information: HEATED OXYGEN SENSOR (HO2S) DIAGNOSTIC

The control module can be used to read off the calculated lambda value from the heated oxygen sensor (HO2S) signal.

Rear heated oxygen sensor (HO2S)

Scheme 215

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 beyond 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 further 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).

There are two rear heated oxygen sensors; one for bank 1 and one for bank 2.

Bank 1 (front cylinder row); cylinders 1, 3, 5 and 7.

Bank 2 (rear cylinder row, closest to the passenger compartment); cylinders 2, 4, 6 and 8.

The heated oxygen sensors (HO2S) can be diagnosed by the engine control module (ECM), and signals from them can be read off

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 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 216

The purpose of the stop lamp switch is to provide the engine control module (ECM) with information indicating whether the brake pedal is depressed or not.

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 stop lamp 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 stop lamp switch can be diagnosed by the engine control module (ECM) and its status (depressed or not) can be read off.

The stop lamp switch is on the pedal box by the brake pedal.

Scheme 217

The air conditioning (A/C) pressure sensor detects the pressure in the high-pressure side of the air conditioning (A/C) system.

The sensor is linear. It is grounded in the control module and supplied with 5 V from the control module. A linear signal (which depends on the pressure in the air conditioning (A/C) system) is transmitted to the engine control module (ECM). Low pressure produces low voltage, high pressure produces high voltage.

The air conditioning (A/C) pressure sensor can be diagnosed by the engine control module (ECM) and the sensor value can be read off.

The air conditioning (A/C) pressure sensor is directly mounted on the air conditioning receiver drier.

The engine control module (ECM) uses a directly connected signal from the transmission control module (TCM) in the start function (activating the starter motor).

Scheme 218

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 accelerator pedal (AP) position sensor consists of a plastic housing with two potentiometers, and an Analog/Digital converter. The potentiometers are connected to a common shaft which is affected by the position of the accelerator pedal (AP).

The accelerator pedal (AP) position sensor transmits an analog and a pulse width modulated (PWM signal to the engine control module (ECM). These signals indicate the position of the accelerator pedal (AP). The digital signal is generated by the sensors Analog/Digital converter.

The analog and digital signals are used at the same time by the engine control module (ECM) to regulate the throttle shutter angle.

The power supply to the two potentiometers is different. The analog potentiometer is supplied with 5 V via the engine control module (ECM). The digital potentiometer is supplied with 12 V via the system relay 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.

Accelerator pedal (AP) position sensor signals can be read off.

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.

Scheme 219

The outside temperature sensor detects the temperature in the surrounding air. The signal is used by the engine control module (ECM) as a substitute value in the event of a fault in certain components or functions and to control certain diagnostic functions.

The sensor is a negative temperature coefficient (NTC) type which is supplied with power from the control module (signal). The resistance in the sensor changes with the outside temperature. This alters the signal 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 outside temperature sensor is positioned in the left door mirror.

The outside temperature sensor can be diagnosed by the engine control module (ECM) and the sensor value can be read off.

Scheme 220

The function of the engine coolant level sensor is to alert the driver if the engine coolant level in the expansion tank is too low.

The sensor is a magnetic reed switch, which is enclosed in a pipe on the bottom of the expansion tank. Around the pipe, on the inside of the expansion tank is a float. This float contains a magnet. When the engine coolant level is above minimum, the float is too high in the tank to affect the switch. However if the engine coolant level falls below the minimum level, the magnetic field acts on the switch.

The sensor is supplied with voltage (signal) from the engine control module (ECM) and grounded in the body. When the engine coolant level in the expansion tank is over a certain level the circuit closes, which produces a low signal. When the engine coolant level is below a certain level the circuit is opened by the engine coolant level sensor, which produces a high signal. When the engine control module (ECM) detects a high signal the information about low engine coolant level is transmitted via the Controller area network (CAN) to the driver information module (DIM), which warns the driver.

Note. There are no functions controlled by the engine which are directly connected to the low coolant level warning lamp. The Engine Control Module (ECM) only transfers the signal which is used by the Driver Information Module (DIM).

The engine control module (ECM) cannot diagnose the engine coolant level sensor.

Scheme 221

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 switch is affected by the oil pressure of the engine.

When the oil pressure exceeds a certain value, the switch in the oil pressure switch 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 switch will close and a low 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 switch.

Scheme 222

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 manifold absolute pressure (MAP) sensor intake is located on the upper rear edge of the engine (passenger compartment side).

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 to the control module. Low pressure results in low voltage, high pressure gives high voltage.

The pressure sensor can be diagnosed by the engine control module (ECM) and the sensor signal can be read off.

Scheme 223

Overview

The fuel pressure and fuel temperature sensors are combined.

The sensor detects the fuel pressure (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.

The fuel pressure-/fuel temperature sensor can be diagnosed by the engine control module (ECM) and its signals (pressure and temperature) can be read off.

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 to the engine control module (ECM). Low pressure results in low voltage, high pressure gives 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.

Note. The absolute pressure is displayed when using parameter read outs 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 volume of the fuel.

Scheme 224

The function of the oil level sensor is to provide the engine control module (ECM) with information regarding the level of engine oil in the oil sump.

The sensor consists of

1. a terminal with three pins
2. integrated electronics
3. 2 capacitive gauge elements
4. a PTC resistor.

The oil level sensor is supplied with 5 V by the engine control module (ECM). The oil level sensor generates a pulse width modulated (PWM) signal for the engine control module (ECM).

The oil level sensor can be diagnosed by the engine control module (ECM).

The pulse-width modulated (PWM) signal from the oil level sensor can be read using parameter readout.

Scheme 225

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 226

The function of the injectors is to spray fuel into the cylinders in the correct spray patterns. This happens sequentially.

The injectors are located under the intake manifold.

The engine control module (ECM) controls the injectors by grounding the valves in pulses.

The injectors can be diagnosed by the engine control module (ECM) and can be activated.

Scheme 227

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. The signal reconnects to the engine control module (ECM) so that diagnostics can be carried out.

Each ignition coil has an 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 228

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)

An oil filter is mounted at the intake channel for the valves to prevent oil contaminants from affecting the function of the reset valves.

The system relay supplies the reset valve with voltage via a fuse. The valve is grounded (control) 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 allows the cam timing to be changed precisely and steplessly.

It is important not to mix up the pipes for the valves when removing/installing the reset valve camshaft.

The engine control module (ECM) can diagnose the camshaft reset valve.

The valves are on the cylinder head above the camshafts. There are four reset valves, two for the inlet camshaft and two for the exhaust camshaft.

Scheme 229

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 electromagnetic valve and 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 evaporative emission system (EVAP) valve can be diagnosed by the engine control module (ECM) and can be activated.

The evaporative emission system (EVAP) valve is on the rear edge of the engine (passenger compartment side).

Scheme 230

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.

AIR CONDITIONING (A/C) COMPRESSOR (CHECK VALVE AIR CONDITIONING (A/C) COMPRESSOR)

The air conditioning (A/C) compressor transports refrigerant, which is necessary for air conditioning (A/C) operation. It is an axial piston compressor with variable displacement. I. E. The compressor has adjustable cylinder displacement which is controlled by a check valve (solenoid). The valve, which is underneath the compressor, can be replaced.

The air conditioning (A/C) compressor is directly mounted on the engine block and is powered by the engine crankshaft via the auxiliaries belt.

Scheme 231

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 / opening 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. See also: START

The starter motor relay is in the relay/fuse box in the engine compartment.

Scheme 232

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) cools the coolant, engine compartment and the condenser when the air conditioning (A/C) compressor is running.

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).

There is an internal diagnostic function in the engine cooling fan (FC). This function transmits a signal to the engine control module (ECM) if the fan is partially or fully blocked. To do this, the engine cooling fan (FC) control module grounds the pulse width modulation (PWM) signal based on a predetermined pattern.

The engine cooling fan (FC) and its control module are behind the radiator.

The engine cooling fan (FC) can be diagnosed by the engine control module (ECM) and can be activated.

Scheme 233

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 can be read off.

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.

Scheme 234

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 (FP) control module is supplied with battery voltage by the fuel pump relay and grounded in the car body. The fuel pump relay is controlled by the central electronic module (CEM) at the request of 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 off.

The fuel pump control module is on the outside on the right-hand side of the fuel tank.

Scheme 235

The valve for variable intake controls the vacuum motor for the damper in the variable intake manifold.

The valve consists of an electro-magnetic valve which controls the air flow between the vacuum tank and the vacuum valve for the damper in the variable intake manifold.

The valve is supplied with voltage from the system relay via fuse and ground (control) internally in the engine control module (ECM). Also see: VARIABLE INTAKE SYSTEM

The valve for variable intake can be diagnosed by the engine control module (ECM).

The valve for variable intake is on the right-hand side of the engine beside the intake manifold.

Scheme 236

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.

If Readiness 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.

Scheme 237

The electronic throttle unit, using the PWM control signal from the engine control module (ECM), regulates the amount of air for engine combustion. This is done using an electronically controlled shutter.

The aluminum electronic throttle unit consists of a round throttle disc on a spindle. The spindle is driven by a DC motor (damper motor), gear wheel and two springs; one for opening and one for return.

By changing the polarity of the power supply, the DC motor can be run in both directions. At one of the limit positions the throttle disc is closed so that minimal air can pass the throttle unit. In the other limit position, the throttle disc is parallel to the air flow. This provides maximum airflow through the electronic throttle unit.

Two permanent magnets in the gear sector on the throttle spindle are used to check the position of the throttle disc. The permanent magnets affect two throttle position (TP) Hall sensors in the cover. The analog signals from the two sensors are transmitted to the engine control module (ECM). The signals are offset. The engine control module (ECM) compares these signals with the stored desired values to check if they are plausible.

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.

Electronic throttle unit.

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.

New software can be downloaded into the engine control module (ECM). 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 engine control module (ECM) is located on the air cleaner (ACL) box in the engine compartment.

The engine control module (ECM) contains a unique code for each car for the immobilizer. The central electronic module (CEM) checks this code at engine start up. The engine will not start if the central electronic module (CEM) detects an incorrect code for the immobilizer. This means that the engine control module (ECM) cannot be switched from vehicle to vehicle.

The engine control module (ECM) must first be "unlocked" using a unique PIN for each car before it can be programmed with a code for the immobilizer. When the PIN has been approved by the engine control module (ECM), the code for the immobilizer can be programmed.

The PIN and the code for the immobilizer are obtained from the Volvo central database and sent out with the software package when software for downloading has been ordered.

All new engine control modules (ECM) have the same PIN which is preprogrammed by the control module supplier. When the engine control module (ECM) has been programmed successfully the original PIN for the car will be programmed in the engine control module (ECM) memory and will replace the preprogrammed PIN code.

Scheme 238

The starter motor (6/25) is supplied with power via the starter motor relay (2/35), the starter motor 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 (U bat ) from the ignition switch (3/1) is transmitted to the engine control module (ECM) via the central electronic module (CEM). 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 solenoid by grounding and powering the coil for the starter motor relay.
4. The relay closes the circuit between the starter motor solenoid and the fuse in the relay/fuse box in the engine compartment, activating the starter motor.
5. The engine control module (ECM) activates the starter motor until the engine starts (the engine speed (rpm) exceeds a certain value)

Auto start

If the ignition key returns to ignition position (position II) before the engine is started, the starter motor continues to run. The starter motor runs until the engine is started or until a certain time has elapsed. The engine temperature dictates the running time of the starter motor

1. 0 °C or higher, approximately 3 seconds
2. less than 0 °C, up to approximately 5 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).

Scheme 239

Both intake camshafts and exhaust camshafts are regulated by the Engine Control Module (ECM). The intake camshafts are located in the middle of the engine, while the exhaust camshafts are located furthest out. The camshafts are divided into two banks.

Bank 1 (front cylinder row); cylinders 1, 3, 5 and 7.

Bank 2 (rear cylinder row, closest to the passenger compartment); cylinders 2, 4, 6 and 8.

The inlet camshafts are driven primarily by the crankshaft and chain, while the exhaust camshafts are driven by a chain from the inlet camshafts.

When each camshaft is set at the factory, it is aligned with the position of the crankshaft. The position of the camshaft in relation to the crankshaft is designated the camshaft 0 position (default setting). During camshaft control (CVVT) the camshaft 0-position is offset so that the cam timing changes. The opening and closing of the intake and exhaust valves can be changed to match the camshaft. Engine performance can be increased, idle quality increased and emissions reduced by regulating the camshaft timing changes.

The engine control module (ECM) detects the position of the camshafts by comparing the signals from the engine speed (RPM) sensor (1) (crankshaft position) and the camshaft position (CMP) sensors (2) (camshaft positions). The engine control module (ECM) then controls the angle of the camshaft by controlling the oil flow to the CVVT unit using the reset valve camshaft (3).

There are diagnostics for this function. See also: CAMSHAFT DIAGNOSTICS (CVVT)

Controlling, reset valve camshaft

Scheme 240

1: Oil filter reset valve camshaft.

2: Oil duct (pressure, inlet).

3: Duct leading to CVVT unit chamber (deployment).

4: Duct leading to CVVT unit chamber (deployment).

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))

Controlling, CVVT units

Scheme 241

The CVVT units are the "Vane" type which means that the CVVT unit rotors are turned by oil pressure on one, or the other, side of the rotor wings.

A: CVVT unit exhaust

B: CVVT unit inlet

1: Timing belt pulley inlet camshaft (primary, inlet camshaft driven by the crankshaft).

2: Timing belt pulley inlet -/exhaust camshaft (secondary, exhaust camshaft driven by inlet camshaft).

3: Oil duct reset valve camshaft (pressure).

4: Oil duct for controlling CVVT unit.

5: Oil duct for return CVVT unit.

6: Spring (CVVT unit exhaust camshaft only).

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 CVVT unit rotor. The rotor (and with it the camshaft) rotates in relation to the timing belt pulley (1) by the oil pressure building up on one or both sides of the rotor vanes in the CVVT unit.

The difference in function between the exhaust camshaft (A) and inlet camshaft (B) CVVT unit is that the exhaust camshaft CVVT unit is equipped with a spring. The force of the spring makes the CVVT unit deploy the camshaft. The function causes faster deployment of the exhaust camshaft at engine start-up, before the oil pressure build in the engine.

Control occurs according to the following during deployment/return of the camshaft.

Scheme 242

A: Exhaust camshaft

B: Inlet camshaft

1. Oil pressure from the lubrication system (1) of the engine.
2. The oil passes the filter for the camshaft reset valve (2) and then on to the reset valve (3).
3. The engine control module (ECM) controls the oil flow to one of the CVVT unit chambers (4) depending on whether it is to be deployed/returned by the camshaft.

The reset valve is controlled by the engine control module (ECM) by high frequency, switching for deployment and return. This results in rapid and precise control. Both camshafts can be controlled up to 40 crankshaft degrees.

Scheme 243

The engine control module (ECM) (4/46) regulates the charge voltage of the generator (GEN) (6/26) (via LIN communication) when requested by the central electronic module (CEM) (4/46) (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 of requested charge voltage from the engine control module (ECM) and the charge current of the generator can be read off.

The alternator control module (ACM) (6/26) transmits information to the engine control module (ECM) regarding any faults). The diagnostic trouble codes (DTCs) are stored in the engine control module (ECM) in the event of a fault. In the event of certain faults, information about these faults is also transmitted to the central electronic module (CEM).

Scheme 244

The variable intake system components consist mainly of

1. Vacuum tank
2. Valve for variable intake
3. Vacuum motor
4. Throttle discs

In order to maintain a high volume of intake air at different engine speeds (RPM) and engine loads, B8444S is equipped with the Variable Intake System. The Variable Intake System divides drawn in air into two volumes. The engine control module (ECM) then regulates the air flow between these volumes using dampers in order to achieve the optimum air flow at specific operating temperatures.

The vacuum from the engine is stored in a vacuum tank (1). The vacuum is then guided to the vacuum motor (3) using the variable intake valves (2). The vacuum motor affects the damper in the intake system.

The variable intake valve is controlled by the engine control module (ECM) (4/46).

The variable intake valve can be activated and the variable intake function can be diagnosed by the engine control module (ECM).

Scheme 245

General

The following components are used for oil monitoring

1. oil level sensor (7/35)
2. engine control module (ECM) (4/46)
3. driver information module (DIM) (5/1).

The oil level sensor, via the driver information module (DIM), is used to inform the driver if oil filling is required.

Detecting the oil level

The integrated electronics of the sensor calculates the oil level using the measured value for the oil temperature.

In order for the correct oil level to be calculated, temporary oil level changes in the oil sump must be added to the calculation, for example when driving on an incline, during cornering and the like. These calculations are performed by the engine control module (ECM) using the oil level sensor signal and a number of other parameters such as the vehicle speed signal and load signal.

Scheme 246

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)
3. cruise control, control unit (3/4)
4. central electronic module (CEM) (4/56)
5. brake control module (BCM) (4/16) (brake pedal position, speed signal)
6. driver information module (DIM) (5/1) (cruise control lamp)
7. transmission control module (TCM) (4/28)
8. electronic throttle unit (6/120)
9. 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.

The cruise control cannot be activated below a certain speed.

Cruise control is disengaged

1. when the driver depresses the 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" position is transmitted on the controller area network (CAN)
5. if the speed deviates too much from the set value
6. when the control system detects a fault that prevents activation.

Scheme 247

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 248

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 249

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 250

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 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 injection period calculated in the base program is limited.

The short-term fuel trim can be read off.

Adaptive functions

Scheme 251

Certain factors, for example, tolerance deviations on certain components such as mass air flow (MAF) sensor and injectors, air leakage on the intake side, fuel pressure etc. affect the fuel / air mix. In order to compensate for this, the engine control module (ECM) has adaptive (self learning) functions. When the engine is new the short term fuel trim varies cyclically around a nominal central line (A) 1.00, with, for example, a 5% change of injection time when fuel trim is in operation.

If there is air leakage for example, the short-term fuel trim will quickly 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).

The adaptive functions are split into various operational ranges based on the load and speed of the engine.

The different adaption ranges can be read off.

The adaptive adjustments of injection time are continuously stored in the engine control module (ECM). This means that, at different operating ratios, the correct mixture ratio is achieved before the heated oxygen sensor (HO2S) reaches operating temperature.

The diagnostic trouble code (DTC) is stored in the engine control module (ECM) if any adaption value is too high or too low.

Scheme 252

General

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 650kPa) 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) with integrated atmospheric pressure sensor
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 using the signal from the atmospheric pressure sensor and fuel pressure sensor. This particularly 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) calculates the desired fuel pressure. A signal is then transmitted to the fuel pump control module indicating the desired fuel pressure. Serial communication between the engine control module (ECM) and the fuel pump control module is used to carry the signal. 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 reached, and if necessary a signal is transmitted to the fuel pump control module requesting that the fuel pressure is adjusted.

The engine control module (ECM) attempts too obtain a constant fuel pressure (approximately 380kPa relative to atmospheric pressure with the engine running).

By-pass valve

When the injectors close when the pressure is too great (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 650 kPa.

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 253

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 one of the cylinders starts knocking there will be a certain type of vibration in the engine block. This vibration is transferred to the knock sensor, which are screwed to the engine block. One knock sensor detects knocking on cylinders 1, 2, 3 and 4. The other one detects knocking on cylinders 5, 6, 7 and 8. The mechanical stress that arises in the piezoelectric material of the knock sensors makes them generate a voltage. With the help of the camshaft position sensor and the impulse sensor, the Engine Control Module (ECM) can then determine which cylinder is knocking.

The knock sensors (KS) also interpret a proportion of 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 sensors (KS) detect 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 254

The following components are used for ignition control

1. engine speed (RPM) sensor (7/25)
2. camshaft position (CMP) sensor (7/172-173, 7/188-189)
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) (7/23-24)
7. transmission control module (TCM) (4/28)
8. spark plugs with ignition coils (20/46-53).

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 sensors (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).

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 255

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/fusebox in the engine compartment and the clutch for the air conditioning (A/C) compressor (8/3). The air conditioning (A/C) compressor which has a variable cylinder displacement is always running during normal driving. Displacement in the compressor is regulated by a solenoid which is controlled by the engine control module (ECM).

The engine control module (ECM) regulates the solenoid (displacement) in relation to the driver's and vehicles' different driving styles. Starting the engine, moving off and acceleration means more regulated displacement so that the A/C compressor has less possible effect on engine torque. The climate control module (CCM) controls all functions in the climate control module which are related to the vehicle interface with the driver and passenger. I. E. the climate control buttons on the dashboard environment panel.

The climate control module (CCM) transmits information to the engine control module (ECM), which determines what must be prioritized. For example, the air conditioning (A/C) compressor in certain extreme cases is switched off completely, regardless of the climate control module (CCM) request. This is to prevent negative engine performance and to protect the air conditioning (A/C) system. As well as the information from the climate control module (CCM), the engine control module (ECM) controls the air conditioning (A/C) compressor based on the information from

1. Air conditioning (A/C) pressure sensor (high pressure side) (7/8)
2. the throttle position (TP) sensor (6/120)
3. the engine coolant temperature (ECT) sensor (7/16).

Scheme 256

The engine control module (ECM) controls, amongst others, the following functions

1. injectors
2. ignition
3. camshafts (CVVT)
4. Evaporative emission system (EVAP) valve
5. throttle angle
6. engine cooling fan (FC)
7. Air conditioning (A/C) compressor
8. fuel pump.

The engine control module (ECM) is supplied with battery power (U bat ) via fuses in the central electronic module (CEM) and in the relay/fuse box, engine compartment.

To prevent certain stored data 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, 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. AC/DC converter
2. DC/AC converter
3. Micro-processor.

The functions which require battery power (U bat ) 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 in the engine control module (ECM).

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 interprets the signals from the different sensors and how the components and functions should be controlled.

The engine control module (ECM) has several self-learning (adaptive) functions. It continually adapts ongoing calculations to changing circumstances (such as wear, air leaks, differences in fuel).

Emissions are kept low through efficient management of the injection period, ignition, evaporative emission system (EVAP) valve, camshafts etc. Faults which affect emissions for example can be detected by running diagnostics for functions and components.

The engine control module (ECM) is located on the air cleaner (ACL) box in the engine compartment. A temperature sensor and atmospheric pressure sensor are integrated in the engine control module (ECM).

The engine control module (ECM) communicates with other control modules using controller area network (CAN) communication or LIN 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 temperature 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 engine control module (ECM).

The substitute value allows the vehicle to be driven and the emissions to be kept at a reasonable level, even though vital functions or 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 internal memory of the engine control module (ECM). The information can be read off 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, LIN and controller area network (CAN) communication. The illustration below displays the same information with the Volvo component designations.

Scheme 257

Scheme 258

Scheme 259

Bi-Xenon uses gas discharge technology and is a headlamp system with moving reflectors. The system combines high and low beams in the same bulb.

It is a statutory requirement (for low beam) for vehicles with this type of bulb to be equipped with headlamps with automatic level control.

Xenon versus Halogen

Xenon

1. has higher color temperature which gives a whiter light
2. reflects from road signs and markings better
3. has lower power consumption. (approximately 2/3).

Worth knowing

1. Daylight has a color temperature of approximately 5000°K. The nearer to natural light, the easier the light is on the eye. Normal H4 bulb: approximately 3200 °K. Volvos gas discharge lamp : approximately 4200 °K
2. The Bi-Xenon system also has the advantage of the high and low beam having the same color light. The human eye finds it easier to react between changes.

BULB

The light source consists of a discharge pipe surrounded by glass which filters out damaging UV radiation.

1. The discharge tube is filled with a number of chemical compounds including the noble gas Xenon
2. A light arc is created by an electrical discharge between two tungsten electrodes
3. Because the bulb does not have a filament it is less susceptible to bumps and vibration
4. Bulb designation: (special for reflector system).
5. Power consumption: 35 W.

BALLAST

An electronic ballast is connected to each headlamp. The ballast functions as a voltage regulator and generates alternating current (AC).

Main tasks

1. Light the bulb
2. Control the light during operation.

To light the bulb an initial voltage of approximately 24, 000 V is required for a very short time (less than 1ms).

The ballast transforms the vehicles 12 V (DC) to 1000 V (AC).

The high tension switch amplifies the voltage a further 25 times.

When the lamp is lit the voltage is reduced to the 100 V required to keep the lamp lit.

Power consumption: 10 W.

Scheme 260

LIGHTING THE HEADLAMP

It normally takes 3 seconds from activation at the light switch with the ignition on to the lamp lighting.

1. Like conventional headlamps the headlamps are out while the engine is cranking and do not light until the engine is running
2. On each occasion that voltage is supplied to the ballast 3 attempts, within 1 second, are made to light the lamp.

COMBINED HIGH AND LOW BEAM

Reflector, left-hand headlamp

Scheme 261

The illustration is a principle sketch showing the different segments of the moving reflector.

The reflector has a complex design where different segments are used depending on whether in high or low beam position.

The reflector is adjustable and can be moved between two fixed points.

1. The reflector is moved 2 mm axially in relation to the bulb
2. The direction of the movement means that position of reflector is also moved slightly vertically.

The bulb is fixed.

The headlamp lens is clear.

AUTOMATIC LEVEL CONTROL

Sensor

The following applies to vehicles without Four-C (Continuously Controlled Chassis Concept)

An inductive position sensor reads off the angle between the bodywork and the left rear control arm. The angle is a measurement of how much the vehicle is leaning (chassis height) and is dependent on weight distribution.

1. The sensor is mounted differently in FWD to AWD
2. The rear electronic module (REM) reads an analog signal (0.5-4.5 V) from the position sensor and converts it to an angle value (±35°), which is transmitted to the central electronic module (CEM)
3. Fully laden vehicles give a signal of 0.5 V which corresponds to minus 35°.
4. The central electronic module (CEM) controls the motors for the headlamp range adjustment (PWM signal) and sets the headlamps vertically.

The following applies to vehicles with Four-C

Two sensors read off the angle between the bodywork and the left and right rear control arms. The angle is a measurement of how much the vehicle is leaning (chassis height) and is dependent on weight distribution.

The sensors are mounted differently in FWD to AWD.

The suspension module (SUM) reads the signals from the sensors and converts them to an angle value. The value is transmitted via the control area network (CAN) to the central electronic module (CEM). The central electronic module (CEM) uses this information to control the motors for headlamp range adjustment.

Level control

Controlled at speeds below 4 km/h

When the ignition is switched on, the position sensor is read off and the headlamp range adjustment motors set the headlamps.

Controlled at speeds above 4 km/h

At greater angle changes during driving the headlamps are controlled. Control is dependent on the time for the system not to react to short term changes such as uneven road surfaces etc.

Calibration

The position sensor must be calibrated after work on the rear suspension. Carry out calibration according to tab DIAGNOSTICS/VEHICLE COMMUNICATION, rear electronic module (REM).

SAFETY

1. In the event of a short-circuit on the high tension side the power supply cuts in less than 10 ms
2. If the high tension circuit is broken (for example by a broken cable, blown bulb or no bulb in the bulb connector) the system attempts to activate the lamp for a time of 700 ms. During this time the high voltage is outside the ballast
3. Approximate temperatures on the components during operation are; Ballast = 130 °C, Bulb holder = 170 °C, Bulb = 400 °C
4. The glass body of the Bi-Xenon-lamp is filled with different gases and metal vapors which are under pressure. The lamp can explode as it is under gas pressure.

Scheme 262

1. High voltage is required to light the Xenon lamp
2. A high voltage unit is attached to each Xenon lamp. It transforms 12 V voltage to approximately 24 000 V, which is necessary to light the lamp. When the lamp is lit the voltage is reduced to the 100 V required to keep the lamp lit
3. On each occasion that voltage is supplied to the high voltage unit an attempt is made to light the Xenon lamp. If this voltage does not exceed 9.5 V within a time span of 200 ms the lamp does not light. If the voltage is too low, after a power consuming start for cold start, the lamp does not light until the engine is running and the generator starts to charge. A new start attempt of the lamp must be made by turning the knob of the light switch till "0" position or parking lamp position and then back to low beam again.

Scheme 263

Scheme 264

An electric motor is controlled by the central electronic module (CEM) via a relay (ordinary high beam relay).

The motor drives a gear wheel which moves the reflector along its guides.

A sensor which detects the position of the reflector is connected to the motor.

1. The electronics in the motor interprets the sensor information and generates a signal
2. The signal is reconnected to the central electronic module (CEM).

If the reflectors are in the wrong position during high beam the reflectors are forced into a safety position

1. the warning lamp (orange) lights in the driver information module (DIM)
2. an error message is also shown in the display in the driver information module (DIM).

If the high beam is activated with the light switch in 0 position, the high beam is only activated as long as the high beam lever is activated for a high beam flash. The headlamp switch must be in the "on" position in order for the high beam lamps to remain active.

Scheme 265

Bi-Xenon, a headlight system with moveable reflector, is based on gas discharge technology. The system combines high and low beam into the same lamp.

Due to legal requirements (regarding low beam) for this type of lamp, the vehicle must be equipped with automatic headlight levelling.

Xenon vs. Halogen

Xenon

1. higher color temperature, which produces a whiter light
2. better reflection of road signs and road markings
3. has lower power consumption.

Good to know

1. Daylight has a color temperature of about 5000 °K. The closer to natural light, the less strain on the eyes. Standard H4 bulb: 3200 °K. Volvo's gas discharge bulb: about 4200 °K.
2. With the Bi-Xenon system, high and low beam generates the same light color. The human eye thus has an easier time adjusting to switches between high and low beam.

LAMP

The light source consists of a discharge tube surrounded by a glass that filters out harmful UV radiation.

1. The discharge tube is filled with a blend of chemical compounds, including the inert gas Xenon.
2. An electric arch is created through an electrical discharge between two tungsten electrodes.
3. Because the lamp does not have a filament, it is less sensitive to bumps and vibrations.
4. Bulb designation: (special for reflector system).
5. Power consumption: 35 W.

An electronic ballast is connected to each headlight. The ballast serves as a voltage regulator and generates alternating current (AC).

Primary tasks

1. Light the bulb.
2. Regulate light during operation.

A initial voltage of about 24, 000 V for a very brief period (less than 1 ms) is required to light the bulb.

The ballast transforms the vehicle's 12 V (DC) to 1000 V (AC).

The high voltage contact amplifies the voltage an addition 25 times.

Once the bulb has been lit, voltage is regulated down to about 100 V, which is required to keep the bulb lit.

Power consumption: 10 W.

Scheme 266

LIGHTING THE LAMP

There is normally a 3 second delay between activation with the light switch or ignition on and the lamp coming on.

1. As with normal headlights, the lamps remain off while the starter motor is cranking and come on once the engine is running.
2. Each time voltage is supplied to the ballast, 3 one-second attempts are made to light the lamp.

Reflector, left headlight

Scheme 267

The illustration is an outline diagram showing the various segments of the moveable reflector.

The reflector has a complex shape in which different segments are used depending on whether high beam or low beam is in use.

The reflector is moveable suspended and is moved between two fixed positions.

1. The reflector is moved 2 mm (0.08 in) axially in relationship to the lamp.
2. The direction of the movements also causes the reflector to shift slightly vertically.

The lamp remains in a fixed position.

The headlight lens is clear.

Sensor

The following applies to cars without Four-C (Continuously Controlled Chassis Concept)