Control Modules - Design and Function - 3 of 3: Overview Volvo S80 I

General information

The rear electronic module (REM) has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system, which continuously monitors itself and the input and output signals.

Reading off the control module identification

VIDA identifies control modules by reading off a number of codes from the control module memory.

The codes contain information about the control module

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. P/N slave nodes (inclination sensor module (ISM))
6. CAN frame period (40 ms for the CAN low-speed network at time of writing)
7. Subcontractor identification plate (ECU-ID).

The rear electronic module (REM) has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system, which continuously monitors itself and the input and output signals.

VIDA identifies control modules by reading off a number of codes from the control module memory.

The codes contain information about the control module

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. P/N slave nodes (inclination sensor module (ISM))
6. CAN frame period (40 ms for the CAN low-speed network at time of writing)
7. Subcontractor identification plate (ECU-ID).

The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and output signals.

VIDA identifies control modules by reading off a number of codes from the control module memory.

The codes contain information about the control module

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.

Identification of generation

See Identification of generation

System overview

See System overview

See Design

See Identification of generation

See System overview

See Design

See Identification of generation

See System overview

The vehicle's electrical system consist of a number of control modules on the CAN and MOST network. The functions of the vehicle can be divided between the different control modules in the vehicle. The vehicle's different functions are implemented via the CAN and MOST network. Each control module is loaded with software that executes functions and monitors the control module through integrated diagnostics.

Incorrect or failed functions in the vehicle usually depend on hardware faults, for example, contact play, oxidation, breakages or short-circuiting.

Software is not worn out and its function is not impaired overtime, however, unforeseeable behavior can occur in software which means it needs to be upgraded. It may also be necessary to upgrade software on account of legislation or when moving to another market.

When starting the control module the primary bootloader starts (PBL) for 20 ms (0.02 seconds). Should the control module receive a programming command (prog) during these 20 ms the control module enters programming mode.

The programming command is sent for approximately 2 seconds so that all control modules have time to execute the command and enter programming mode. If no programming command is sent the control module's application software takes over the function of the control module.

If a reset command is sent to the control modules in programming mode, the control modules will enter normal operating mode.

The primary bootloader means it is always possible for a control module to enter programming mode even if the application software has been corrupted, for example, during unsuccessful downloading.

The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and output signals.

The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and output signals.

Reading the control module identification

VIDA identifies control modules by reading off a number of codes from the control module memory.

The codes contain the following information about the control module

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.

Reading off control module identification

VIDA identifies control modules by reading off a number of codes from the control module memory. The codes contain information about the control module

1. hardware P/N (control module without software)
2. hardware serial number (control module without software)
3. software P/N
4. software number, diagnostics
5. serial number, side impact sensor.

The following information can also be read off from the control module memory

1. hardware part number for occupant weight sensor (OWS) (certain markets and models only)
2. software part number for occupant weight sensor (OWS) (certain markets and models only)

VIDA identifies the control modules by reading off a number of codes from the control module memory.

The codes contain information about the control module's

1. hardware P/N (control modules without software)
2. hardware serial number (control modules without software)
3. side impact sensor serial number
4. software P/N
5. P/N diagnostic software.

See System overview

Scheme 497

On the front suspension are two acceleration sensors, one on each spring strut. These measure the speed of vertical change. The sensors are supplied with 5 V by the suspension module (SUM). When the vehicle is stationary, the output signal from the sensors is approximately 2.5 V. When there is vertical movement the signal will oscillate around this value; the greater the movement the greater the deviation. The control module calculates a damper position and speed from the acceleration. The control module uses the position and speed to determine the required damping force.

There are diagnostics for the acceleration sensors.

Scheme 498

There are two position sensors at the rear suspension. The position sensor measure the position of the right and left-hand control arms in relation to the car body. The vertical position of the shock absorber is calculated based on this position. The sensors are supplied with 5 V by the suspension module (SUM). When the vehicle is stationary, the output signal from the sensors is approximately 2-3 V. When there is vertical movement the signal will oscillate around these values; the greater the movement the greater the deviation.

Note. The values move in different directions on the left and right-hand sides. Upwards body movement results in increased voltage on the left-hand side and a voltage drop on the right-hand side.

There are diagnostics for the position sensors, which must be calibrated after replacement.

Scheme 499

There are three acceleration sensors on the car body. Two are under the headlamps and one is behind the left-hand wheel arch in the cargo compartment. The acceleration sensors are supplied with 5 V by the suspension module (SUM). When the vehicle is stationary, the output signal from the sensor is approximately 2.0 V. When there is vertical movement the signal will oscillate around 2.0 V; the greater the movement the greater the deviation. The control module assesses the information from the acceleration sensors and then controls the damping forces to the car body depending on the selected driving mode.

Note. The acceleration sensors are installed with the connector turned upwards and are fixed in position. Otherwise movement could result in incorrect values, resulting in poor cornering characteristics for example.

There are diagnostics for the acceleration sensors.

Scheme 500

Note. The illustration is of a front shock absorber.

Each wheel has an adjustable shock absorber. The damping force in the shock absorber is altered using a valve in the shock absorber which is affected by the current in the surrounding solenoid.

The suspension module (SUM) controls the current to the solenoid. Lower current gives lower damping forces, high current higher damping forces.

If there is no current to the solenoid, the shock absorber is set to a failsafe mode, corresponding to conventional passive shock absorbers.

There are diagnostics for the solenoids.

Scheme 501

Above the ventilation shutter in the center console is a keypad which is used to select the driving mode (ACTIVE CHASSIS SETTINGS).

There are three different driving modes which can be selected

1. COMFORT
2. SPORT
3. ADVANCED.

In the "COMFORT" driving mode, ride comfort is prioritized. In "SPORT" mode driving pleasure is prioritized.

The "ADVANCED" mode sets the shock absorbers to a characteristic optimized for more aggressive driving.

The selected driving mode is confirmed by an LED which lights in the keypad.

The keypad is connected via a cable directly to the suspension module (SUM).

The lighting has a rheostat function, i. e. the light level is set via the light switch in exactly the same was as for the combined instrument panel and the radio.

There are diagnostics for the keypad.

Scheme 502

The Four-C switch is beside the other switched on the lower section of the climate control module (CCM).

There are two different driving modes which can be selected

1. COMFORT
2. SPORT.

The "COMFORT" driving mode is active when the switched is not activated. The "SPORT" mode is activated when the switch is pressed. This is confirmed by a green LED in the switch.

In the "COMFORT" driving mode, ride comfort is prioritized. In "SPORT" mode driving pleasure is prioritized.

The switch on the climate control module (CCM) is connected to the central electronic module (CEM). The central electronic module (CEM) is in turn connected to the suspension module (SUM) via the Controller area network (CAN).

There are diagnostics for the climate control module (CCM).

Scheme 503

The control module has a built-in diagnostic system, Volvo Diagnostic, which continuously monitors internal functions as well as input and output signals.

VIDA identifies control modules by reading off a number of codes from the control module memory.

The codes contain information about the control module

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 (part of the software).

See System overview

See Design

See System overview

CAN (Controller Area Network) is a standardized system for multiplex-communication. Volvo has developed a new standard for multiplex communication - VOLCANO. VOLCANO is a further development of CAN and operates with real time operation and prioritizing. The description of prioritizing is developed from VOLCANO but is designated CAN.

The standard for Control area network (CAN) specifies

1. That two cables should be used (CAN H and CAN L)
2. Which voltage levels should be used
3. What a message should look like
4. How transfer errors should be handled.

Scheme 504

The CAN H and CAN L cables must not be confused with HS CAN and LS CAN which are speeds on the Controller area network. CAN H and CAN L are a way of distributing signals within the multiplex communication network.

Communication occurs through two cables. These two cables are paired together. CAN H is always white and CAN L is always green.

The cables are made of copper and are easily identified by the green and white coloring.

The voltage levels for communication occur using differential voltage levels.

The reason for communicating using paired cables and differential voltage levels is that the network becomes less sensitive to interference.

The same message is transferred simultaneously by both cables, but different voltage levels are used.

1. Binary 1 = 2.5 V on both CAN H and CAN L.
2. Binary 0 = 4 V on CAN H and 1 V on CAN L.

Average voltage level is 2.5V.

Scheme 505

The message consists of the following components

1. Identifier ("flag"), which indicates the message identity and prioritization
2. Data information (value, information etc.)
3. Check sum, used to check that the message has arrived correctly
4. Stop signal, which indicates that the message has finished.

A complete Controller area message is called a frame.

The Controller area network (CAN) is monitored and controlled by the central electronic module. When the central electronic module detects a fault in the controller area network a diagnostic trouble code (DTC) is set in the central electronic module. There are different diagnostic trouble codes depending on the type of malfunction detected.

Types of error which are handled are

1. Electrical faults
2. No communication from the control module
3. Faulty communication.

Increasing demands for further functionality in the car, both by statutory requirement and customers, have led to an increased complexity in the car.

This has in turn driven the development of more flexible electronic systems. The Controller area network (CAN) is a result of this research. The network allows a large number of different commands and messages to be transmitted and received on the same cable. Previously each command or message required a separate cable. By using the network functionality has increased without increasing the number of cables.

The number of commands and messages that can be handled by the network depends on the speed of the network and the length of the message / command. The Volvo network which is based on a Controller Area Network (CAN), can transmit over 500 different signals and approximately 100 messages (also known as frames). Each message can contain several signals, for example a message to the rear electronic module can contain all the signals for how the tail lamps should be lit.

The network is made up of a number of control modules (sometimes called nodes) which are connected to each other serially via two communication cables. Each control module is supplied with power and grounded individually and receives messages /commands via the two communication cables. In both networks (high and low speed sides) the control modules are serially connected. In the event of an open-circuit those control modules beyond the open-circuit will not be able to communicate with other parts of the network.

CAN (Controller Area Network) is a standardized system for multiplex communication. Multiplex communication means that you can transmit messages between one or more control modules on the same wires without communication between the various control modules disrupting one another. Volvo has produced a new standard for multiplex communication, known as VOLCANO. VOLCANO is a further development of CAN and works with real-time processing, as well as prioritization. The description of prioritization is based on VOLCANO but named CAN.

The standard for Control area network (CAN) specifies

1. That two cables should be used (CAN H and CAN L)
2. Which voltage levels should be used
3. What a message should look like
4. How transfer errors should be handled.

The network is made up of a number of control modules (sometimes called nodes) which are connected to each other serially via two communication cables. Each control module is supplied with power and grounded individually and receives messages /commands via the two communication cables. In both networks (high and low speed sides) the control modules are serially connected. In the event of an open-circuit those control modules beyond the open-circuit will not be able to communicate with other parts of the network.

Scheme 506

The network consists of two parts: a high speed side (HS CAN) which transmits signals/messages between the central electronic module (CEM) and control modules mainly in the engine compartment, and a low speed side (LS CAN) which transmits signals/messages between the central electronic module (CEM) and control modules in the passenger compartment and the luggage compartment.

The interface between the high and low speed sides is supplied by the central electronic module (CEM) which converts the transmission speed up or down for communication between the two network sides.

Scheme 507

The data link connector is located in the passenger compartment near the driver's station, cables for high-speed side (HS CAN) and low-speed side (LS CAN) are connected to the data link connector.

Scheme 508

1. Pin 3 LS CAN (low-speed side) (H-cable)
2. Pin 4 Chassis ground
3. Pin 5 Signal ground
4. Pin 6 HS CAN (high-speed side) (H-cable)
5. Pin 11 LS CAN (low-speed side) (L-cable)
6. Pin 14 HS CAN (high-speed side) (L-cable)
7. Pin 16 Voltage feed

Note. The data link connector's other connections may be used by other functions. This service information only describes connections related to CAN.

The CAN network is monitored by the central electronic module (CEM). When the central electronic module (CEM) detects a fault in the CAN network, a diagnostic trouble code (DTC) is stored in the central electronic module (CEM). There are various types of diagnostic trouble code (DTC), depending on the type of fault.

Types of error which are handled are

1. Electrical faults
2. No communication from the control module
3. Faulty communication.

Increasing demands for further functionality in the vehicle, both statutory requirements and customers, have led to increased complexity in the vehicle.

This, in turn, has encouraged developments towards more flexible electrical systems. The CAN-net (Controller Area Network) is a result of this research. The network permits the transmission and receipt of a large number of different commands and messages on the same wiring. Earlier, every command or message required a separate cable. Using networks has allowed functionality to be expanded without increasing the number of cables.

The number of commands and messages which can be handled on the network depends on factors such as the network speed and the length of the message or command. The Volvo network which is based on a control area network (CAN), can transmit over 500 different signals and approximately 100 messages. These messages are also called frames. Each message can contain several signals, e. g., a message to Rear electronic module (REM) can contain all signals for how the tail lights should be lit.

The RTI control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system, which continuously monitors itself and the input and output signals.

VIDA identifies the control modules by reading off a number of codes of RTI memory.

The codes contains information about the RTI control module's

1. hardware P/N (control modules without software)
2. hardware serial number (control modules without software)
3. software P/N
4. P/N diagnostic software.

Transmission, General information

The basic parameters for shifting are the accelerator pedal (AP) position and the vehicle speed.

The gear shift quality is determined by the torque control by reading off speed changes of the transmission input shaft and comparing the calculated value.

This is used to calculate the pressure setting for the clutches and brakes.

The control unit has built-in diagnostics, Volvo Diagnostics, which continually monitor the system and the input and output signals.

Reading the control unit identification

VIDA identifies control units by reading the number of codes from the control unit memory.

The codes contain information on the control unit as follows

1. hardware component number (control unit without software)
2. hardware series number (control unit without software)
3. software component number
4. diagnostic software component number

Certain values deviate from those contained in the signal specifications, see Signal description. Transmission control module (TCM) . This is because read off values are calculated and filtered by the control module. In certain cases the engine must be running to obtain the relevant values.

See System overview

The control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system. This system continuously monitors its own system and the input and output signals.

VIDA identifies the control modules by reading off a number of codes from the control module memory.

The codes contain the following information about the control module

1. the hardware P/N (control modules without software)
2. the hardware serial number (control modules without software)
3. the software P/N
4. the diagnostic software P/N

Scheme 509

Data from the siren (Siren Control Module) to the upper electronic module contains configuration and status information. This data is carried via serial communication.

When the alarm is activated the siren sends continuous status signals to the upper electronic module.

The siren is equipped with a battery and a built-in battery charger so that it is independent of the vehicle power supply. The battery charger maintains battery voltage in the integrated battery. When the alarm is activated the power supply is monitored for the siren and serial communication between the siren and the upper electronic module. The siren sounds if the car's power supply to the siren is broken or if communication between the upper electronic module and the siren is interrupted. The battery and the battery charger in the siren cannot be changed separately. The entire siren must be replaced if it is faulty.

The siren is located in a protected position under the fender liner in the front right-hand wheel arch. The siren must be configured after replacement. Configuration is carried out using VIDA.

The siren can be diagnosed.

Scheme 510

The Sun Roof Module is operated by one switch. The switch is located in the same unit in the roof as the front reading lamps and the courtesy lighting. The sun roof can be opened, closed and tilted.

The sun roof is powered by a motor in the roof in front of the sun roof. The position of the sun roof is determined by two optical sensors.

There are diagnostics for the sun roof.

Scheme 511

The Mass Movement Sensor detects movement in the passenger compartment using radio waves at 2.450 GHz. The Doppler effect principle is used to determine if the frequency of the received microwave has been modified in comparison to the transmitted microwave. Any change in frequency is interpreted as a movement in the car. When movement is detected, a trigger signal is sent to the upper electronic module which activates the alarm.

The movement sensor is located in the headlining in the center of the car. This allows the sensor to cover as large an area as possible.

There are diagnostics for the movement sensor.

Scheme 512

The rain sensor module optically senses water on the windshield. An infra red beam of specific intensity lights a section of the windshield. The intensity of the reflected beam is measured and compared to the intensity of the transmitted beam. If there is water on the surface of the windshield, the beam distorts, reducing the intensity of the beam. If the beam is not reflected completely it is interpreted as rain on the windshield and the windshield wipers are started.

The signals from the upper electronic module are carried via serial communication. The rain sensor transmits the signals to the upper electronic module. These signals request a particular windshield wiper speed (depending on the amount of rain falling on the windshield), indicate that a sudden large splash has hit the windshield and register the light conditions outdoors.

The rain sensor is located in front of the rear view mirror on the inner side of the windshield. A special windshield is used on cars with rain sensors.

There are diagnostics for the rain sensor.

Scheme 513

There are a number of lamps inside the passenger compartment. The lamps include four reading lamps and a general courtesy lamp.

The front left and front right reading lamps and the courtesy light are located in the same unit in the roof, just above the rear view mirror. The two rear reading lamps are located in the roof above the rear seat.

The five lamps transmit control signals to the control module. These signals allow the control module to determine the status of the lamps and switches This allows faults such as broken bulbs, open circuits or jammed switches to be detected.

The five control signals are distributed as input signals at the four inputs in the upper electronic module. The control signal for the courtesy lighting shares the same inputs as control signals for the front reading lamps. The rear reading lamps each have their own input.

Two different lighting times can be programmed using VIDA depending on the requirements of the customer.

1. Short lighting time which is the time from when the door is unlocked or closed or from when the engine is switched off until the interior lighting goes out. The time can be set between 5 and 255 seconds. Normal setting is 30 seconds
2. Long lighting time, which is the time from when a door is left open or from when a light is lit using a button to when the interior lighting goes out. The time can be set between 0 and 255 minutes. Normal setting is 10 minutes.

There are diagnostics for all lamps in the inner roof lighting.

Scheme 514

The remote control can be used to lock and unlock the doors, open the trunk lid, to activate the approach lighting, and to activate the panic alarm (certain markets).

The receiver for the remote control is located in the rear view mirror and transmits signals to the upper electronic module. These signals determine

1. which function should be activated
2. at which frequency the receiver receives the signal from the remote control
3. which of the remote controls transmitted the signal
4. the signal strength received from the remote control.

Up to six remote controls can be stored in the upper electronic module. The control module stores the identity and PIN for each remote control.

The remote control identity and PIN are also stored in the central Volvo database When replacing the upper electronic module, this data is transmitted to the car. This means that the remote controls do not need to be replaced and can be used with the new upper electronic module.

There are two different types of remote control, depending on whether the car is a late or an early model. The two variants are programmed into the control module in different ways. The early variant has an 8 digit PIN. The late variant has one 8 digit and one 16 digit PIN.

The early version and late version differ by chassis number.

Information regarding at which production plant a car was manufactured can be found in the VIN number. The 7th character from the right in the VIN indicates the production plant.

If the seat and power door mirrors in the car have a memory function, these functions are affected by the remote controls which are stored in positions 1, 2 or 3. The memory functions store the seat and power door mirror settings at the time the car was locked using one of these remote controls. Next time the car is unlocked using the same remote control, the seat and the power door mirrors move to the same settings.

The remote control battery can be replaced.

Scheme 515

The rear view mirror has an automatic anti-dazzle function for when light from behind the car is too bright in the mirror (option in certain markets).

One photo sensor on the front of the rear view mirror, and one on the rear side compare light intensity. When the intensities differ by a specified amount the anti-dazzle function compensates to the required degree. The upper electronic module receives and manages the signals from the two photo sensors.

The anti-dazzle function can be set to the customer requirements. The selectable values are Light, Normal and Dark. Initial setting is Normal.

LEDs for the seat belt reminder are located in the rear view mirror, above the mirror lens.

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

The upper electronic module (UEM) has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system, which continuously monitors itself and the input and output signals.

VIDA identifies control modules by reading off a number of codes from the control module memory.

The codes contain information about the control module

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.