Engine Management Systems - Design and Function: Other Volvo S80 I рестайлинг

Downloading software and replacing the control module

See Downloading software and replacing the control module

See Function

See Downloading software and replacing the control module

See Function

Malfunction indicator lamp (MIL) activation

Emissions related diagnostic trouble codes (DTC) are stored even when it is lit. A counter counts down to determine when the malfunction indicator lamp (MIL) should be lit. The conditions for lighting the malfunction indicator lamp (MIL) vary depending on the diagnostic trouble code (DTC) that is stored.

Faults that have been diagnosed in the automatic transmission may affect emissions and the automatic transmission may request the activation of the malfunction indicator lamp (MIL).

Scheme 143

5 cylinder engines have two heated oxygen sensors (HO2S).

6 cylinder engines have two three-way catalytic converters (TWC) and therefore four heated oxygen sensors (HO2S). The probes work in parallel in two banks. Bank 2 is for cylinders 4 to 6.

The front heated oxygen sensor (HO2S) is a lineal type and functions with current control. Therefore it is possible to measure the signals from the heated oxygen sensor (HO2S) with a multimeter. The rear heated oxygen sensor (HO2S) is a binary type as with earlier heated oxygen sensors (HO2S).

Twin heated oxygen sensor (HO2S) control starts and is active when

1. the front probe has started control
2. the rear probe has reached operating temperature
3. three-way catalytic converter (TWC) temperature has reached +300 °C (572 °F) (calculated by the control module)
4. engine speed (RPM) is >1500 RPM at light load - not at idle speed or under full load.

Twin heated oxygen sensor (HO2S) control is interrupted at fuel shut-off, during misfiring or in the event of a fault in

1. EVAP system
2. catalytic converter
3. heated oxygen sensor (HO2S) heating
4. mass air flow (MAF) sensor.

The control module checks the heated oxygen sensors (HO2S) continually and can register the following types of fault

The prerequisites for the various checks are summarized below.

Scheme 144

Probe monitoring begins after probe preheating diagnostics are complete. Diagnostic trouble code (DTC) ECM-280A/290A is stored if there is a fault in the front heated oxygen sensor (HO2S) or its wiring causing the signal to deviate from its permitted range.

The control module carries out the following checks of probe control functions.

1. Checking offset (signal too high)

The control module compares the front and rear adaptation values. A diagnostic trouble code (DTC) is stored when the values deviate by more than 3%.

Note. The fault may be in the front or rear heated oxygen sensor (HO2S) circuit.

2. Checking HO2S dynamics (signal too low)

The control module monitors the aging of the probe by checking its dynamics when switching between lean and rich mixtures. The diagnostic trouble code (DTC) is stored if the control module registers that the probe is operating too slowly.

3. Overheating from the HO2S preheating (signal missing)

The control module monitors cross-induction from the probe preheating. Diagnostic trouble code (DTC) is stored when cross induction exceeds the permitted value.

4. In the event of a faulty signal, four sections must be checked

1. A diagnostic trouble code (DTC) is stored if the control module registers that the signal is above 4.8 V for too long.
2. A signal is transmitted so that the problem signal is modified if no faults are found in the probe preheating or in the rear probe and the control module registers that the signal from the front probe does not deviate from lambda=1. A diagnostic trouble code (DTC) is stored if the signal still does not deviate from lambda=1.
3. A diagnostic trouble code (DTC) is stored if the control module registers that the signal from the front probe is showing a lean fuel mixture while the signal from the rear probe is showing a rich mixture.
4. A diagnostic trouble code (DTC) is stored if the control module registers that the signal from the front probe is showing a rich fuel mixture while the signal from the rear probe is showing a lean mixture.

Rear heated oxygen sensor (HO2S), electronic check

Diagnostic trouble code (DTC) ECM-2A0A/2B0A is stored if there is a fault in the rear heated oxygen sensors (HO2S) or its wiring causing the signal to deviate from its permitted value.

Rear heated oxygen sensor (HO2S), aging

The control module checks the rear heated oxygen sensor (HO2S) dynamics. The control module checks that the probe has registered both lean and rich fuel mixtures. If this is the case, a signal is transmitted so that the probe signal is changed. Diagnostic trouble code (DTC) ECM-2A1A / 2B1A is stored if the rear probe has still not registered lean or rich fuel mixture. The diagnostic trouble code (DTC) is also stored if the switch over time from lean to rich fuel mixture is too long.

Front heated oxygen sensor (HO2S), preheating

Checking that the heating circuit begins after dew point has been reached. The control module registers an electrical fault and checks the probe's lambda value. A diagnostic trouble code (DTC) for a faulty signal is stored if the value deviates from 1 within a set time after the control module interprets that heated oxygen sensor (HO2S) preheating is not working.

Preheating, rear heated oxygen sensor (HO2S)

Checking that the heating circuit begins after dew point has been reached. The control module registers electrical faults in the front probe. The control module measures the resistance in the heater element so that the probe temperature (which is continuously compared with a temperature model) can then be calculated. A diagnostic trouble code (DTC) for a faulty signal is stored if the temperature in the probe is lower than a designated value in the temperature model.

Scheme 145

The three-way catalytic converter (TWC) stores oxygen found in the exhaust gases and uses it to make toxic gases more environmentally friendly. The catalytic converter is a 3-way catalytic converter in which HC (hydrocarbons) and CO (carbon monoxide) are oxidized and NO x (nitrous oxide) is reduced. As the three-way catalytic converter (TWC) ages, its ability to store oxygen is reduced. The conversion capacity of the three-way catalytic converter (TWC) is reduced and unburned residue which is harmful to environment is released. To reduce the environmentally damaging emissions, the engine control module (ECM) checks the efficiency of the three-way catalytic converter (TWC). In brief, this check is carried out as follows.

Two heated oxygen sensors (HO2S) are used to check the three-way catalytic converter (TWC) one upstream and one downstream of the catalytic converter. The main function of the heated oxygen sensors (HO2S) is to measure the oxygen content in the exhaust gases so that the engine control module (ECM) can maintain the fuel-/air mixture at around lambda=1. This mixture provides optimum three-way catalytic converter (TWC) efficiency. To determine catalytic converter efficiency the amplitude of the heated oxygen sensor (HO2S) signals is compared (amplitude is a measure of signal oscillation).

When three-way catalytic converter (TWC) efficiency is good and the fuel-/ air mixture is normal, the front heated oxygen sensor (HO2S) signal switches between rich and lean while the rear heated oxygen sensor (HO2S) signal is even. When three-way catalytic converter (TWC) efficiency is poor and the fuel-/ air mixture is normal, the rear heated oxygen sensor (HO2S) signal switches between rich and lean because the exhaust gases are passing straight through the three-way catalytic converter (TWC) without being converted.

If the amplitude of the rear sensor becomes too great in relation to the amplitude of the front sensor for a number of checks, a diagnostic trouble code (DTC) will be stored for catalytic converter efficiency.

CAN communication

ECM (Engine Control Module) sends out and receives the following signals via the network

Anti-lock Braking System (ABS)

Provides information so that the Engine Control Module (ECM) can determine whether any misfiring is due to road condition or to a fault in the engine management system. Also provides a vehicle speed signal, (goes via the DIM first).

Climate Control Module (CCM)

Provides information to the Engine Control Module (ECM) that A/C is selected and the request that the A/C compressor functions.

Central Electronic Module (CEM)

Is the "main computer" in the network and coordinates required information between other modules. It also controls diagnostic function by connecting the data link connector (DLC) to the network for programming and reading off diagnostic trouble codes (DTCs) and parameters.

Driver Information Module (DIM)

Provides the Engine Control Module (ECM). with information about vehicle speed.

Data Link Connector (DLC)

When reprogramming and downloading new software and fault-tracing the initiation request is transferred from VIDA via data link connector (DLC) pin 7 (also called Communication link) to the CEM which closes

2 internal relays and opens communication with the network.

The serial communication via the data link connector (DLC) (pin 7, Communication line) is only used by the authorities and certain other workshops in the USA/CDN for reading off OBD II codes using the Generic Scan Tool.

Electronic Fan Control Module

Receives a signal from the Engine Control Module (ECM) about which speed the engine cooling fan (FC) should run at.

Electronic Throttle Module (ETM)

The following signals are sent out on the network from the electronic throttle module and taken up by the engine control module (ECM)

1. Provides information about current throttle position.
2. Request to DIM via ECM to light ETS lamp
3. Faults discovered in the Electronic Throttle Module (ETM) are stored as diagnostic trouble codes (DTCs) in the Engine Control Module (ECM)

Steering Wheel Module (SWM)

Provides information to the Engine Control Module (ECM) that the cruise control is selected and that the driver requests a change in the cruise control speed.

Transmission Control Module (TCM)

The following signals are sent out on the network from the engine control module (ECM) and taken up by the TCM

1. Engine load
2. Throttle opening
3. Acknowledgment of torque limiting

The following signals are sent out on the network from the Transmission Control Module (TCM) and taken up by the ECM

1. Torque limiting request stage I and II
2. Request to operate the malfunction indicator lamp (MIL)
3. Constant idle speed compensation (P/N position) signal

Scheme 146

General

The 6 cylinder turbo has the variable camshaft on the exhaust side. The camshaft has 15 camshaft degrees (30 crankshaft degrees) between its outer positions. The Continuous Variable Valve Timing (CVVT) unit for the turbocharged engine is bright metal.

The normally aspirated 6 cylinder has the variable camshaft on the intake side. The camshaft has 20 camshaft degrees (40 crankshaft degrees) between its outer positions. The Continuous Variable Valve Timing (CVVT) unit for the turbocharged engine is painted black.

The difference in the camshaft setting between the turbocharged and the normally aspirated engines is that the turbocharged engine uses a more compact Continuous Variable Valve Timing (CVVT) unit.

The Continuous Variable Valve Timing (CVVT) valve has different versions depending on whether it is used on the intake or exhaust side. The valve cannot be incorrectly installed.

The normally aspirated engine mainly uses the variable camshaft to obtain good starting capacity and good idling quality. The variable camshaft provides a torque increase of approximately 10% in the engine speed (RPM) range between 1500 - 3000 RPM. At certain engine speeds the camshaft adjustment is also used to keep emissions down.

The turbocharged engine mainly uses the variable camshaft to minimize emissions.

Scheme 147

Diagnostics and fault tracing are carried out as before using VIDA. However from the 1999 model year onwards the Volvo Scan Tool (ST) (which could only communicate serially via the data link connector (DLC)) has been replaced by a new communication unit called the VCT 2000 (Volvo Communication Tool 2000) which can communicate with the modules via the network.

Car communication

The following can be read off using car communication

Read diagnostic trouble codes (DTCs)

ME 7.0 engine management system contains approximately 135 diagnostic trouble codes (DTC). Each diagnostic trouble code (DTC) can give information on whether the fault depends on an open-circuit, short-circuit to supply voltage or short-circuit to ground. This gives a combined total of 405 different diagnostic trouble codes (DTCs).

The following output signals/components can be activated

Activation

1. Injectors (sequentially)
2. Power stages/ignition coils (sequentially)
3. air conditioning (A/C) relay (compressor clutch)
4. Output signal engine coolant temperature sensor
5. Indicator lamp CRUISE
6. Econometer signal to the Driver information module (DIM)
7. Engine cooling fan (FC) (3 speeds)
8. Engine speed (RPM) to DIM
9. Electronic Throttle System warning lamp
10. EVAP canister shut-off valve
11. Turbocharger (TC) control valve
12. Canister purge (CP) valve
13. Fuel pump (FP) relay
14. Malfunction Indicator Lamp (MIL)
15. Heating front heated oxygen sensor (HO2S)
16. Heating rear heated oxygen sensor (HO2S)
17. Continuous Variable Valve Timing (CVVT) camshaft control valve
18. Interlock function (starter motor relay), USA/CDN only

Reading off plotter

Here curves and values for approximately 90 parameters can be read off. As before a maximum of 3 can be read at the same time.

Activating diagnostic functions

This is a new function for activating the different test phases in the following on-board diagnostic (OBD) systems

1. Return Fuel Lacking System (RFLS)
2. Pulsed secondary air injection system (PAIR)

Fuel trim

Control of the fuel/air mixture occurs following known principles. However the signal from the front probes are of a more linear character. This means that the Engine Control Module (ECM) notices small changes throughout the voltage range and can control the fuel/air mixture much faster and more precisely than before.

6 cylinder engines have been equipped with double catalytic converters. Each catalytic converter serves three cylinders.

The heated oxygen sensors (HO2S) contain as before a PTC resistor which is supplied with voltage from the Engine Control Module (ECM) in order to reach operating temperature quickly. The oxygen sensitive ceramic which measures oxygen levels in the exhaust gases consists of Zirconium dioxide.

If the Engine Control Module (ECM) determines that the ambient air is very cold and damp it may delay starting to heat up the heated oxygen sensors (HO2S) a few seconds. This is to prevent the heated oxygen sensor (HO2S) warm ceramic being touched by cold drops of water and then cracking.

Front heated oxygen sensor/s (HO2S)

The output signal characteristic is between 0 - 4.7 V. The short-term fuel trim control area is between 0.75 and 1.25.

Signal characteristics

1. high voltage = rich mixture
2. low voltage = lean mixture

Rear heated oxygen sensor/s (HO2S)

The rear heated oxygen sensor/s (HO2S) has/have more importance in controlling fuel/ air mix than previously. The rear heated oxygen sensor/s (HO2S) have been moved nearer to the front heated oxygen sensor/s (HO2S), just in front of the metal monolith in the catalytic converter.

Signal characteristics

1. high voltage = rich mixture
2. low voltage = lean mixture

Camshaft Position (CMP) Sensor

The camshaft position (CMP) sensor is a new version and operates using a different signal characteristic to previously.

The sensor consists of an MRE (Magnetic Resistance Element). It is a permanent magnet with 2 special resistors which are connected in series with each other, where one end is voltage supplied and the other goes to ground. The output signal is an analog sine curve which passes through an analog/digital converter in the camshaft position (CMP) sensor before being sent on to the engine control module (ECM).

When a tooth on the pulse wheel nears the sensor the magnetic field is bent and affects the resistor located nearest to the ground, resistance affects the voltage and the output signal to the Engine Control Module (ECM) is low. When the same tooth continues past the sensor the magnetic field follows and so affects the other resistor which is located nearest to the voltage supply, this resistor affects the voltage so that the output signal to the Engine Control Module (ECM) is high. The magnetic field swings backwards and forwards between the teeth on the pulse wheel and the Engine Control Module (ECM) senses the signals between the teeth, partly before and partly after the sensor.

The pulse wheel has 4 teeth. The Engine Control Module (ECM) calculates the time interval from one tooth to the next and can decide exactly which cylinder must be supplied with fuel and spark respectively.

Scheme 148

Sensors and functions which are different to previous types are marked in bold text .

Scheme 149

Sensors and functions which are different to previous types are marked in bold text .

Scheme 150

ME 7.0 is a further development of Motronic 4.4 and has similarities regarding sensors and their functions. ME 7.0. is on all B6304S, B6284T and B52X4T engines from model year 1999. The biggest new feature regards the communication between the ECM and other modules. Communication occurs via network.

The following modules communicate by ECM (Engine Control Module) via the network

1. ETM (Electronic Throttle Module), see information pamphlet "Engine Management System Denso, ME 7.0, S70, V70, C70".
2. TCM (Transmission Control Module).
3. ABS (Antilock Braking System).
4. CEM (Central Electronic Module), Central computers in the network and shifts between the network's high speed section (250 kbps) and its low speed section (125 kbps). The high speed section includes the following modules: ECM, ETM, TCM, ABS and also the CEM.
5. DLC, data link connector for connecting to VIDA.
6. DIM (Driver Information Module), combined instrument panel.
7. CCM (Climate Control Module).
8. SWM (Steering Wheel Module).

ME 7.0 contains a large number of sensors that operate according to the previously known principles and sends its information by analog signals to the ECM.

As applies to controlled components these also function to known principles, with a few exceptions. These exceptions are covered in the following information.

For more information about the electronic throttle unit system and related components such as the throttle unit, accelerator pedal sensor, stop lamp switch, clutch pedal sensor switch and brake pedal position sensor, see Design and Function .

Scheme 151

Turbocharger (TC) boost pressure is Controlled By The Boost Pressure Control (BPC) valve whose pressure regulators are affected by the pressure from the turbocharger (TC). The Engine Control Module (ECM) receives information about current throttle angle, this in turn affects the boost pressure control. The Engine Control Module (ECM) affects the controlling pressure using the turbocharger (TC) control valve.

When the pressure increases the Boost Pressure Control (BPC) valve pressure regulators Are Affected. When boost pressure has increased to the maximum permissible value the Boost Pressure Control (BPC) valves open and part of the exhaust gases bypass the turbocharger (TC) turbines which limits the boost pressure. Turbocharger (TC) control is constant as a combination between the throttle angle and the turbocharger (TC) control valve opening to obtain the maximum calculated torque.

Controlling turbocharger (TC) boost pressure

When the Engine Control Module (ECM) determines that a higher boost pressure is permissible, the turbocharger (TC) control valve opens further and a proportion of the pressure acting on the Boost Pressure Control (BPC) valve pressure servos is allowed through to the turbocharger (TC) inlets. In this way the control pressure is reduced, the Boost Pressure Control (BPC) valves open later and turbocharger (TC) pressure can increase.

The Engine Control Module (ECM) affects the turbocharger (TC) control valve by grounding one of the terminals with a fixed frequency, where the signals duty cycle determines how much the valve should open and therefore how much the boost pressure can increase.

Boost pressure reduction

The charge pressure is reduced when driving in first gear and reverse with engine speed (RPM) below 3000 RPM to reduce the risk of wheel spin. If the engine has an automatic transmission the automatic transmission receives information from the TCM about when reduced charge pressure is required, for example when shifting. If the car has a manual transmission the Engine Control Module (ECM) determines which gear is selected based on the transmission and final drive gear ratios, engine speed (RPM) and vehicle speed.

On cars with automatic transmission there is also boost pressure reduction in the winter mode.

Boost pressure reduction, continued

Boost pressure can also be reduced to protect the engine from damage. If the knock sensors (KS) detect that the engine is knocking above a given threshold value, and ignition has been retarded and the air/fuel mixture has been enriched, the Engine Control Module (ECM) will reduce the boost pressure until knock ceases.

A reduction in boost pressure also takes place If There Is a risk of the engine overheating. If the Engine Coolant Temperature (ECT) sensor indicates that the temperature has exceeded 118 °C (244.4 °F), the Engine Control Module (ECM) lowers the boost pressure to reduce heat generation.

Automatic high altitude compensation

Because the Engine Control Module (ECM) determines boost pressure using the signal from the intake air pressure sensor, there is automatic boost pressure control compensation when driving at altitude and in different temperatures. The engine power is not therefore noticeably affected by air density or temperature.

When altitude exceeds 2000 meters above sea level the Engine Control Module (ECM) cannot compensate boost pressure any further because of the low air density.

Boost pressure monitoring

The Engine Control Module (ECM) constantly monitors boost pressure using the mass air flow (MAF) sensor and the intake air pressure sensor. If boost pressure exceeds permitted levels the Engine Control Module (ECM) shuts the turbocharger (TC) control valve so that the engine torque can only be controlled through limiting the throttle opening. A diagnostic trouble code (DTC) is stored at the same time.

If the calculations display too low boost pressure a diagnostic trouble code is stored.

If a fault occurs in a component that affects boost pressure calculation , the Engine Control Module (ECM) will always limit throttle opening.

If there is a fault in any of the sensors the boost pressure control goes over in an open loop. This means that it is controlled by fixed duty cycle which is a direct function of accelerator pedal (AP) position and engine speed (RPM).

Communication via network

See Communication via network

Continuous Variable Valve Timing (CVVT)

See Continuous Variable Valve Timing (CVVT)

See Fuel trim

Functions/components controlled

See Functions/components controlled

Input signals

See Input signals

Turbocharger (TC) control system B6284T

See Turbocharger (TC) control system B6284T

See Communication via network

See Continuous Variable Valve Timing (CVVT)

See Fuel trim

See Functions/components controlled

See Input signals

See Turbocharger (TC) control system B6284T