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

READING OFF THE CONTROL MODULE IDENTIFICATION

VIDA (Volvo scan tool) 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.

OVERVIEW

The purpose of the compass is to display the direction in which the front of the car is pointing.

The compass is integrated in the rear view mirror. The compass display is integrated in the top right-hand corner of the rear view mirror. Eight different compass points can be displayed, using the abbreviations N, NE, E, SE, S, SW, W and NW.

1. N : North
2. NE : Northeast
3. E : East
4. SE : Southeast
5. S : South
6. SW : Southwest
7. W : West
8. NW : Northwest.

Scheme 593

The driver door module (DDM) uses LIN communication to communicate with the control panel for power windows and door mirror operation in the driver's door. The central locking control panel in the driver's door in directly connected to the driver door module (DDM). The driver door module (DDM) receives input signals from the control panels, at which time it performs the function or uses CAN or LIN communication to forward the signal to the control module that will perform the function.

The following functions can be controlled via the control panels

1. all power windows
2. all windows up/down (instead of child-proof lock)
3. operating the door mirrors
4. central locking.

Scheme 594

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

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

The following functions can be controlled via the control panels

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

The control module can be identified by means of reading off a number of codes.

The codes contain information about the control module

1. hardware P/N (control module without software)
2. P/N for the rear door control module
3. hardware serial number (control module without software)
4. serial number for the hardware for the rear door control module
5. software P/N
6. diagnostic software P/N.

READING THE CONTROL MODULE IDENTIFICATION

The control module can be identified by means of reading off a number of codes.

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.

OPERATION IN THE EVENT OF A ROOF FAULT

Operation in the event of a roof fault is a function that makes roof operation (opening, closing and load assistance) possible even if certain sensors signal faults.

The function can only be activated when CAN communication with the Convertible Roof Module (CRM) works. Other requirements for roof operation, such as temperature in the hydraulic pump, supply voltage and the vehicle's speed still apply.

In the event of operating the roof with a non-functioning sensor, a warning sound signal is sounds from the Driver information module (DIM) and a text message is displayed. If the operating button is then released and pressed again within 5 minutes, the roof continues to operate, after 2 seconds, at the same time as the audible signal sounds. If roof operation, in the event of a roof fault, temporarily stops, keep the button depressed so that the roof continues its operation. If the load assistance function is used in the event of roof fault operation, the roof sections can only be lowered.

TO DECIDE OPERATION CONDITIONS WHEN THE MALFUNCTION WAS DETECTED

Malfunctions in a system may be intermittent. It is important to remember this when troubleshooting a possible malfunction cause. If the malfunction is not in the vehicle when it is in the workshop you can miss a malfunction cause since the values may be correct when troubleshooting takes place. A good indication of when the malfunction first occurred for the first time are the frozen values that can be read out for every diagnostic trouble code.

The frozen values are stored immediately after a malfunction has been detected. Most parameters in the frozen values are the same for all malfunctions and indicate a general condition when a malfunction has been detected, e. g., engine RPM, load, coolant temperature, vehicle speed and battery voltage. Some of them have been selected to give a better understanding of the specific malfunction.

Diagnostic trouble code ECM-903F Electronic throttle unit, internal malfunction cam be used as an example of how frozen values can be used.

The first possible source indicated in VIDA (Volvo scan tool) is the voltage feed to the electronic throttle unit and then continues by suggesting that you check the battery and charging system. However, the battery's condition when the vehicle is in the workshop does not necessarily show the battery voltage when the malfunction was detected.

Instead, the best information is found in the frozen values, that is, voltage that the Engine control module (ECM) detects when Electronic throttle module (ETM) indicated the malfunction.

However, you should remember that this is not an indication of voltage feed to Electronic throttle module (ETM), it is voltage feed to Engine control module (ECM). If Engine control module (ECM) according to frozen values has had good voltage the battery was okay. Therefore, voltage feed to Electronic throttle module (ETM) should be checked separately.

Frozen values for ECM 903F

1. Condition, heated oxygen sensor control bank 1 = LR: Closed circuit with two sensors
2. Condition, heated oxygen sensor control bank 2 = LR: Closed circuit with two sensors
3. Calculated load = 4.71%
4. Engine temperature = 87 °C
5. Fuel adaption, quick adjustment, bank 1 = 15.63%
6. Fuel adaption, slow adjustment, bank 1 = -0.78%
7. Fuel adaption, quick adjustment, bank 2 = 23.44%
8. Fuel adaption, slow adjustment, bank 2 = -0.78%
9. Engine speed = 760 RPM
10. Vehicle speed = 0 km/h
11. Boost pressure = 30%
12. Battery voltage = 12.50 V
13. Throttle angle, desired value = 14.84%
14. Air mass = 23.8 kg/h
15. Outside temperature = 33 °C

In this case we assume that the vehicle had low battery voltage in the workshop. However, as can be seen in the frozen values, battery voltage was okay when the malfunction occurred, so this was probably not the cause.

This is an example of how frozen values can be used to increase efficiency of troubleshooting and avoid using too much time for incorrect troubleshooting. This prevents troubleshooting and fixing a malfunction that was not the real cause of the problem that was to be solved.

The odometer reading (km) is sometimes included in frozen values in Engine control module (ECM). This enables a quick comparison with the odometer so that you can assess if the malfunction occurred as part of the troubleshooting and can be ignored. For example, CAN-network-related diagnostic trouble codes are saved when the battery voltage drops during work on the vehicle since passenger compartment lighting and other loads drain the battery.

The frozen values indicate odometer reading in km. If you multiply this value by factor 0.62 you obtain driving distance in miles. Current driving distance in both miles and km can be read out with VIDA (Volvo scan tool).

Keep the following in mind when using frozen values for troubleshooting.

The frozen values to be used with care are those stored for the CAN-net and are related to diagnostic trouble codes for Electronic throttle module (ETM).

If Electronic throttle module (ETM) detects that communication to Engine control module (ECM) is interrupted, then malfunction flags will be generated in Electronic throttle module (ETM). These malfunction flags will be sent to Engine control module (ECM) first when communication on the CAN-net works again.

This means that Engine control module (ECM) will store the diagnostic trouble codes first when Electronic throttle module (ETM) delivers them, which in turn means that it is at this point in time that the frozen values are saved. For Electronic throttle module (ETM) this means that the frozen values will be from a point in time after the malfunction first occurred.

The control module can be identified by means of reading off a number of codes.

The codes contain information about the control module

1. hardware P/N (control module without software)
2. P/N for the rear door control module
3. hardware serial number (control module without software)
4. serial number for the hardware for the rear door control module
5. software P/N
6. diagnostic software P/N.

The control module can be identified by means of reading off a number of codes.

The codes contain information about the control module

1. hardware P/N (control module without software)
2. P/N for the rear door control module
3. hardware serial number (control module without software)
4. serial number for the hardware for the rear door control module
5. software P/N
6. diagnostic software P/N.

VIDA (Volvo scan tool) 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.

ROOF OPERATION

Opening the roof

Scheme 595

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

Closing the roof

Scheme 596

Load assistance

Scheme 597

UP

Before the roof is raised, the front roof cylinder locks the front roof section's lock to the body. At the same time the catches for the rear roof section lock, which occurs out of sight (the roof is in the cargo compartment). As the hydraulic sequence is the same as when the roof closes, the trunk lid's hydraulic cylinders are also activated. Sometimes the catches for the trunk lid's upper section are not unlocked (the lock catch motor has not been activated). This means that the hydraulic cylinder's pistons work and try and open the trunk lid. The results in the lower section of the trunk lid moving compared with the upper section. This is a design feature and not a fault.

DOWN

Scheme 598

The electric retractable hardtop consists of two link systems, one for the roof and one for the trunk lid. Three roof sections and the parcel shelf are on the roof's link system. The trunk lid's upper and lower sections are on the trunk lid's link system.

When the roof is opened, the roof sections are placed on top of each other in the cargo compartment. The rear roof section with rear windshield comes to rest on the top, the front roof section in the middle and the roof's center section at the bottom.

The roof is operated using a hydraulic system that is controlled by the Convertible Roof Module (CRM).

The roof can be opened/closed manually in an emergency.

This service information only describes the mechanical and hydraulic components of the roof.

Scheme 599

1. Control module with power stage
2. Pump motor
3. Pump
4. Terminal for 15 supply and CAN
5. Terminal for power supply (30 supply) and ground.

The electrical power steering module (EPS) consists of one unit with the following main components

1. control module
2. pump motor
3. pump.

The electrical power steering module (EPS) is under the right-hand headlamp. The electrical power steering module (EPS) can only be replaced as one unit. The control module, pump motor and pump cannot be replaced as separate components.

Note. When replacing the electrical power steering module (EPS), the vehicle must be configured with new software to match the profile of the car.

Control module

The control module is built into the pump motor casing. All the electrical terminals are on the top of the control module. The control module has logics for all functions which enables it to read, write and store software and diagnostic trouble codes (DTCs). The control module also manages all communication with the other control modules via the controller area network (CAN).

The control module contains a number of power stages, field effect transistors (FET). The field effect transistors control the output of the pump motor upon request from the control module. The control module also has a built-in NTC temperature sensor (low temperature results in high resistance, high temperature in low resistance). This allows the control module to diagnose, limit or disengage the power steering if an excessive temperature is registered or there are other faults in the control module.

Hydraulic pump (pump/pump motor)

The hydraulic pump consists of a pump and a pump motor. The pump is in an oil reservoir. The pump motor, which drives the pump, is under the reservoir. The pump motor is a brushless DC motor. The pump motor also has Hall sensors. The Hall sensor provide the control module with information about the speed of the pump motor, and therefore the prevailing hydraulic pressure (which is indirectly speed dependent). This allows the control module to control and diagnose the pump motor.

VIDA (Volvo scan tool) 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.

see OVERVIEW

Scheme 600

The ignition switch powers certain functions in the engine control module (ECM) via fuses in the front integrated relay/fuse box and central electronic module (CEM). The ignition switch also supplies the engine control module (ECM) with signals such as

1. "wake up" signal
2. start signal.

"wake up" signal

The ignition switch transmits a high signal to the engine control module (ECM) via the central electronic module (CEM) indicating that the ignition switch is in position I or II. The system prepares for start-up (for example by temporarily activating the fuel pump relay).

Start signal

The ignition switch transmits a high signal to the engine control module (ECM) when the ignition switch is in position III.

The engine control module (ECM) activates the starter motor relay. The relay in turn activates the starter motor. See also: START

The fuse in the front integrated relay/fuse box supplies current to the ignition switch.

The central electronic module (CEM) has diagnostics for the ignition switch.

Scheme 601

The engine control module (ECM) uses a directly connected signal from the transmission control module (TCM) in the start function (activating the starter motor). See also: START

Scheme 602

The function of the Premair sensor is to meet legal requirements for low emission variants. The sensor is located on the radiator.

The sensor measures the temperature of the radiator and transmits the value, together with a check of its own condition, to the Engine control module (ECM). During the engine's warm-up phase the Engine control module (ECM) carries out a number of checks of the received information in order to determine the status of the sensor and the radiator.

The sensor communicates with the Engine control module (ECM) via LIN (Local Interconnect Network)communication, a standardized serial communication method. Transmitted information is encrypted.

The Premair sensor is diagnosed by the Engine control module (ECM). The sensor is secured to the radiator and cannot be replaced separately.

Scheme 603

The air conditioning (A/C) pressure sensor detects the pressure in the low pressure side of the air conditioning (A/C) system. See also: REGULATING THE AIR CONDITIONING (A/C) COMPRESSOR

The air conditioning (A/C) pressure sensor has a pressure sensing switch which is supplied powered by the fuse and grounded (signal) in the engine control module (ECM). The air conditioning (A/C) pressure sensor is affected by the pressure in the low-pressure pipe of the air conditioning (A/C) system (thick pipe).

The engine control module (ECM) cannot diagnose the air conditioning (A/C) pressure sensor.

Scheme 604

The function of the oil pressure switch is to warn the driver about low oil pressure via the driver information module (DIM).

The oil pressure switch has a pressure sensing switch which is powered (signal) by the engine control module (ECM) and grounded in the cylinder block. The oil pressure sensor is affected by the oil pressure of the engine.

When the oil pressure exceeds a certain value, the switch in the oil pressure sensor will open. A high signal is then sent to the engine control module (ECM).

If the oil pressure is below a certain value, the switch in the oil pressure sensor will close and a high signal will be sent to the engine control module (ECM). The engine control module (ECM) then transmits a CAN signal to the driver information module (DIM) to light the indicator lamp for low oil pressure.

The oil pressure sensor is on the cylinder block.

The engine control module (ECM) cannot diagnose the oil pressure sensor.

Scheme 605

The fuel pump control module powers the fuel pump and regulates the output of the pump. The fuel pressure changes with the output of the pump.

The fuel pump control module is supplied with battery voltage by the fuel pump (FP) relay and is grounded in the car body. The fuel pump (FP) relay is controlled by the central electronic module (CEM) when requested by the engine control module (ECM).

The engine cannot be started if the power supply to the fuel pump control module is faulty because the fuel pump will not then be powered.

The fuel pump control module is controlled by the engine control module (ECM) via serial communication. The fuel pump control module then controls the fuel pump by transmitting pulse width modulated (PWM) voltage on the ground lead for the fuel pump. This means that the voltage drop across the pump changes, and with it the output of the fuel pump. See also: FUEL PRESSURE REGULATION

There are no diagnostics for the fuel pump control module. The engine control module (ECM) has diagnostics for fuel pressure regulation and the associated components. See also: FUEL PRESSURE REGULATION, DIAGNOSTICS

The pulse-width modulated (PWM) signal from the engine control module (ECM) to the fuel pump control module can be read using VIDA (Volvo scan tool).

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

Scheme 606

The function of the fuel pump is to ensure that the pressure is correct at the delivery lines for the injectors when requested by the fuel pump control module.

The fuel pump consists of

1. An electrical pump with an integrated safety valve
2. A pressure equalization valve. This valve equalizes rapid pressure peaks which occur, for example, when the injectors close during engine braking. It also contains a non-return valve which ensures that the pressure in the system does not drop when the engine is switched off
3. Fuel level sensor
4. Fuel filter, cannot be replaced separately
5. Relief valve, releases fuel into the pump housing
6. Ejector pump, continuously fills the pump housing with fuel. The fuel always flows from the fuel pump through the ejector and back to the pump housing.

The fuel pump is supplied with battery voltage by the fuel pump control module and is grounded in the car body via the fuel pump control module.

The engine control module (ECM) has diagnostics for the fuel pump function to ensure that the pressure is correct. See also: FUEL PRESSURE REGULATION, DIAGNOSTICS

The fuel pump can be activated and its status read off using VIDA (Volvo scan tool).

The pressure in the fuel rail can be measured by connecting a manometer to a nipple. This nipple is on the right-hand end of the fuel rail.

Scheme 607

The task of the stop lamp switch is to provide the engine control module (ECM) with information about the position of the brake pedal.

A signal is transmitted to the engine control module (ECM) when the brake pedal is pressed. The engine control module (ECM) disengages the cruise control (if activated). The brake pedal sensor also disengages cruise control.

The 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 engine control module (ECM) can diagnose the brake light switch. The status of the switch can be read using VIDA (Volvo scan tool).

The stop lamp switch is on the pedal box by the brake pedal.

Scheme 608

The air conditioning (A/C) pressure sensor detects the pressure in the high-pressure side of the air conditioning (A/C) system. See also: REGULATING THE AIR CONDITIONING (A/C) COMPRESSOR

The sensor is linear. It is grounded in the control module and supplied with a 5 Volt current from the control module. A linear signal (between 0-5 V depending on the pressure in the air conditioning (A/C)) is transmitted to the control module. Low pressure produces low voltage, high pressure produces high voltage. The air conditioning (A/C) pressure sensor is affected by the pressure in the high-pressure pipe of the air conditioning (A/C) system (narrow pipe).

The engine control module (ECM) can diagnose the air conditioning (A/C) pressure sensor. The sensor value can be read off using VIDA (Volvo scan tool).

See OVERVIEW .

The engine control module diagnoses its own internal signals and functions as well as the signals and functions of connected components.

See OVERVIEW .

The engine control module (ECM) diagnoses both internal signals and functions as well as signals and functions from connected components.