Engine Components - Specifications: Other Volvo S80 I

Preheating, front heated oxygen sensor (HO2S)

Resistance approximately 3 ohms (at 20°C)

Scheme 196

Binary probe

Preheating, rear heated oxygen sensor (HO2S)

Resistance approximately 10 ohms (at 20°C)

Scheme 197

Individually mounted ignition coil with integrated power driver

Scheme 198

Multi electron

Scheme 199

NTC resistance.

Scheme 200

Linear pressure sensor. Measurement range 0 -3100 kPa.

Air conditioning (A/C) pressure switch (Pressostat)

Pressure controlled switch.

Scheme 201

Pulse ratio controlled valve. Resistance 29.7 1.4 ohms

Scheme 202

Solenoid valve. Resistance 17 1 ohms

Scheme 203

Piezo electric lineal pressure sensor.

Scheme 204

Frequency controlled mechanical relay

Scheme 205

Mechanical relay. Resistance coil 96 ohms

Scheme 206

Two pole mechanical relay. Resistance 80 ohms

Scheme 207

Mechanical relay. Resistance 80 ohms

Scheme 208

Self-adjusting.

Scheme 209

Self-adjusting.

Scheme 210

Two separate switches.

Scheme 211

Level indicator

Scheme 212

Pressure controlled switch.

Mass Air Flow (MAF) sensor

The mass airflow sensor gives engine control module (ECM) information about the air mass that passes through the sensor, which then is sent into the engine as well as the temperature of that air.

The values should be regarded as approximate.

MASS AIR FLOW (MAF) SENSOR

COMPARISON TABLE

A/C pressure sensor

The sensor gives the engine control module (ECM) information about the pressure in the air conditioning (climate unit).

The values should be regarded as approximate.

A/C pressure sensor

Air conditioning (A/C) pressostat

The values should be regarded as approximate.

Air conditioning (A/C) pressostat

Air conditioning (A/C) relay

Air pressure sensor intake manifold (MAP)

Air pressure sensor intake manifold (MAP) gives the engine control module (ECM) information about the pressure of the air being sent into the engine.

The pressure is given in kPa and sinks with increased engine load (vacuum).

The values should be regarded as approximate.

Air pressure sensor intake manifold (MAP)

Clutch pedal sensor

Clutch pedal sensor

Note. The table shows which values apply when taking readings from the piston rod for the clutch pedal position sensor

Engine coolant temperature (ECT) sensor

The engine temperature sensor gives engine control module (ECM) information about the coolant temperature. Engine control module (ECM) sends the signal on to Driver information module (DIM).

The values should be regarded as approximate.

Engine coolant temperature (ECT) sensor

Intake air temperature (IAT) sensor inlet

Intake air temperature (IAT) sensor inlet

Impulse sensor

The inductive sensor gives engine control module (ECM) information about the crankshaft's position and speed.

The values should be regarded as approximate.

IMPULSE SENSOR

Knock sensor

The knock sensor gives engine control module (ECM) information if it registers damaging knocking ignition. Some engines have both a front and rear knock sensor.

The values should be regarded as approximate.

KNOCK SENSOR

Heated oxygen sensors (HO2S)

Front heated oxygen sensor (HO2S)

Scheme 213

The front heated oxygen sensor (HO2S) is used to provide the engine control module (ECM) with information about the remaining oxygen content of the exhaust gases in front of the three-way catalytic converter (TWC). This information is used by the engine control module (ECM) so that it can continually check the combustion so that lambda=1. lambda=1 is the ideal fuel-air ratio, with 14.7 kg air/1 kg fuel.

The heated oxygen sensor uses current control and its signal characteristic is linear. With a linear signal characteristic, the amplitude of the signal curve is low when changing the oxygen content in the exhaust gases. The probe consists of a preheating element (see "Pre-heating heated oxygen sensors" as follows) 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 cable harness.

The engine control module (ECM) can diagnose the heated oxygen sensor. For further information, see Heated Oxygen Sensor (HO2S) diagnostic . VIDA can be used to read off the calculated lambda value from the heated oxygen sensor.

Rear heated oxygen sensor (HO2S)

Scheme 214

The rear heated oxygen sensor is used to provide the Engine Control Module (ECM) with information about the remaining oxygen content of the exhaust gases behind the three-way catalytic converter (TWC). This information is used by the Engine Control Module (ECM) to check the function of the three-way catalytic converter (TWC). This check is carried out when the conditions for the catalytic converter diagnostics have been met. The rear heated oxygen sensor 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. For further information, see Catalytic converter diagnostic .

The heated oxygen sensor (HO2S) uses voltage control. The signal characteristic is binary. With a binary signal characteristic, the amplitude of the signal curve changes considerably when changing the oxygen content in the exhaust gases. Otherwise its components and function are the same as the front heated oxygen sensor (HO2S).

The engine control module (ECM) can diagnose the rear heated oxygen sensor. The signal can be read using VIDA.

Preheating of the heated oxygen sensors (HO2S)

The heated oxygen sensor (HO2S) only functions above a certain temperature, approximately 300 °C. The normal operating temperature is between 300-900 °C. The heated oxygen sensors (HO2S) are electrically pre-heated so that operating temperature is rapidly reached. This also ensures that the heated oxygen sensors (HO2S) maintain a normal operating temperature and to prevent condensation which could damage the heated oxygen sensor (HO2S).

The heater element in the probe consists of a positive temperature coefficient (PTC) resistor. The system relay supplies the heater element with voltage. The element is grounded in the engine control module (ECM). When the control module grounds the connection a current flows through the PTC resistor. When the heated oxygen sensor (HO2S) is cold, the resistance in the PTC resistor is low and a large current will flow through the circuit. The current from the Engine Control Module (ECM) is pulsed at first to prevent condensation damage to the heated oxygen sensor (HO2S). Depending on the temperature, allowances are made for factors such as the dew point. As the temperature in the PTC resistor rises, the resistance rises, the current falls and switches in stages to a constant current. The pre-heating time for the front heated oxygen sensor (HO2S) is short, approximately 20 seconds. The rear short-term fuel trim takes longer to warm up. This is to prevent damage to the probe. The pre-heating time for the front heated oxygen sensor (HO2S) is short, approximately 20 seconds.

Probe preheating begins as soon as the engine is started. The heater element heats the heated oxygen sensors (HO2S) to approximately 350 °C. The probes maintain this as a minimum temperature.

The engine control module (ECM) can diagnose the heater element.

Engine speed (RPM) sensor

The engine speed (RPM) sensor provides the Engine Control Module (ECM) with information about the speed and position of the crankshaft. The Engine Control Module (ECM) is able to use the signal from the engine speed (RPM) sensor to determine when a piston is approaching top dead center (TDC). However it is unable to use the signal from the engine speed (RPM) sensor to determine whether the piston is in the combustion stroke or whether the exhaust valve is open (exhaust stroke). The signal from the camshaft position (CMP) sensor is also required to determine the operating cycle of the engine.

The signal from the engine speed (RPM) sensor is also used to check the engine for misfires (misfire diagnostics).

Cars with automatic transmissions have a steel ring with punched holes. This steel ring is welded to the edge of the carrier plate. In both cases, there is 6° between each hole. This arrangement creates a hole for each tooth. There are 360° in one revolution. 6° between each hole means that there are 60 holes. However one hole is not drilled/punched, to create a reference position (tooth) for the crankshaft. This reference position is 72° before the top dead center (TDC) of cylinder 1 on a 5 cylinder engine.

The engine speed (RPM) sensor is at the rear of the engine above the flywheel.

The sensor is inductive with a permanent magnet. An alternating current is induced in the sensor when the flywheel/carrier plate passes the engine speed (RPM) sensor. The generated voltage and frequency increases with the engine speed (RPM).

The signal varies between 0.1 - 100 V (AC) 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 tooth passes the engine speed (RPM) sensor, the voltage and frequency drop momentarily to zero, even though the engine is still running. This allows the Engine Control Module (ECM) to determine the position of the crankshaft.

If the signal from the engine speed (RPM) sensor is incorrect or missing, the control module will use the signals from the camshaft position (CMP) sensor, on the condition that the position of the camshaft has been adapted and the car can be driven if there is no signal.

The engine control module (ECM) can diagnose the engine speed (RPM) sensor. The sensor value (engine speed (RPM) can be read off using VIDA.

Camshaft position (CMP) sensor

The Engine Control Module (ECM) uses the signals from the camshaft position (CMP) sensor and the engine speed (RPM) sensor to establish the operating cycle of the engine. This enables the engine control module (ECM) to

1. start the engine more quickly
2. control the correct ignition coil and injector
3. function as a substitute for the engine speed (RPM) sensor
4. check the camshaft continuous variable valve timing (CVVT).

The pulse wheel on the camshaft has five teeth with different gaps which correspond to a specific cylinder.

For further information, also see Knock sensor (KS) , Engine speed (RPM) sensor and see Camshaft control (CVVT) .

The sensor, which is a magnetic resistor with a permanent magnet, is grounded in the control module and supplied with current 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 0-1 V and is low when a flank passes the camshaft position (CMP) sensor.

The camshaft position (CMP) sensor is positioned at the rear of the engine on the camshaft with continuous variable valve timing (CVVT).

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

Knock sensor (KS)

Cars of model year 1999-2000 have a knock sensor. Cars from model year 2001 are equipped with two knock sensors (KS).

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 positioned on the cylinder block below the intake manifold.

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

Engine coolant level sensor

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 chassis. 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 215

The function of the main relay (system relay) is to supply certain components with voltage.

The relay is mechanical and has a closing 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 engine control module (ECM) can diagnose the main relay.

The main relay is in the relay/fusebox in the engine compartment.

Air conditioning (A/C) relay

The air conditioning (A/C) relay controls the A/C compressor. When the climate control module (CCM) requests A/C control, a signal is transmitted to the engine control module (ECM) via the controller area network (CAN) to activate the relay. The engine control module (ECM) temporarily deactivates the relay in the event of

1. full load acceleration
2. too high engine coolant temperature.

The relay is mechanical. It has a closing / breaking function and is supplied with power from the system relay.

In the rest position the circuit in the relay is open.

The system relay supplies the coil and the relay with power. The relay activates when the coil is grounded in the engine control module (ECM), the circuit closes and the A/C compressor is supplied with power via the relay voltage output.

The relay coil is grounded (signal) when the engine control module (ECM) receives a signal via the Controller area network (CAN) from the climate control module (CCM) to activate the relay and start the compressor.

Fuel pump (FP) relay

The fuel pump (FP) relay supplies the fuel pump with power. The relay also cuts the power to the pump when the ignition is switched off or if the engine stops. The central electronic module (CEM) also cuts the power to the relay if the supplemental restraint module (SRS) transmits a message indicating that an airbag has deployed.

The central electronic module (CEM) activates and deactivates the relay when requested by the engine control module (ECM) (via the Controller area network (CAN).

When the ignition is switched on, the engine control module (ECM) sends a signal to the central electronic module (CEM) via the controller area network (CAN) to run the fuel pump (FP) for one seconds. This is so that the pressure increases in the fuel system, shortening the start time.

When the flywheel in the engine rotates (generating a signal from the engine speed (RPM) sensor), the engine control module (ECM) will transmit a request to the central electronic module (ECM) via the Controller area network to start the fuel pump (FP). In the event of the engine stopping, the Engine Control Module (ECM) cancels the "activated fuel pump" signal. The central electronic module (CEM) then switches off the fuel pump (FP).

There is a directly connected cable between the engine control module (ECM) and the central electronic module (CEM). In the event of a fault in the Control area network (CAN), this cable is used by the "activated fuel pump" signal.

Scheme 216

Cars from model year 1999-2000 have an air distribution valve. The air distribution valve supplies the injectors with air. This results in better volumetric efficiency, more effective combustion and therefore cleaner exhaust emissions. The valve is also used for idle air trim but is also slightly open at higher engine speeds.

The valve is directly mounted on the inlet hose for the electronic throttle module (ETM). The valve is connected to a hose which supplies air to the air-shrouded injectors via a distribution pipe.

The valve has its own ignition driver stage and solenoid and is supplied with 12V. The valve is controlled steplessly by the Engine Control Module (ECM) using a variable pulse ratio (duty-cycle) which opens or closes a shutter in the valve.

The valve works primarily during cold starts and when idling, to minimize the release of carbon dioxide and hydro-carbons whist maintaining performance and driveability. This is partly because the size of fuel drops is smaller with fuel mixed with air and does not adhere as easily to the walls of the intake manifold when they are cold and damp. This also reduces fuel consumption when cold starting and cuts the warm up time for both the engine and the three-way catalytic converter (TWC).

The total calculated volume of air to be released into the combustion chamber is distributed between both the Electronic Throttle Module (ETM) and the air distribution valve. The input signals to the Engine Control Module (ECM) which affect the operation of the air distribution valve are: the position of the throttle, engine speed (RPM)/position sensor, engine coolant temperature (ECT) sensor, ambient air pressure and ambient air temperature.

The air distribution valve can be diagnosed by the Engine control module (ECM) and can be activated using VIDA.

Injectors

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

The injectors are in the intake manifold.

It is essential that the injectors are correctly installed with no air leakage around them. Fuel leakage from the top of an injector when it is not activated may lead to starting and driving problems.

The engine control module (ECM) controls the injectors using a pulse width modulation (PWM) signal.

The engine control module (ECM) can diagnose the injectors. The injectors can be activated using VIDA.

Air-shrouded injectors

Cars from model year 1999-2000 have air-shrouded injectors.

The injectors are in the air distribution pipe which is in the intake manifold.

The lower section of the injectors has 2 openings in the side where air can enter.

When the needle in the injector starts to rise, the openings are exposed. This allows air to flow in to the center of the valve at high speed, and the fuel and air are finely distributed and mixed.

When the needle rises further, the injector nozzle opens and the air/fuel mixture is released into the combustion chamber.

Evaporative emission system (EVAP) valve

The evaporative emission system (EVAP) valve is used to open/close the connection between the EVAP canister and the intake manifold. The valve controls the flow of hydro-carbons (fuel vapor) from the EVAP canister to the engine intake manifold using the vacuum in the intake manifold. This ensures that hydro-carbons stored in the EVAP canister are used in the engine combustion process.

The valve is an electro-magnetic valve which is powered from the system relay. When the valve needs to be opened, it is grounded internally in the engine control module (ECM). The evaporative emission system (EVAP) valve is closed when in the standby position (open-circuit).

When the control module requests that the EVAP canister should be emptied (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. The valve is grounded using a pulse width modulation (PWM) signal, allowing the control module to govern the extent to which the valve opens and adapting the emptying of the canister according to how full it is, engine speed (RPM) and load etc.

The engine control module (ECM) can diagnose the evaporative emission system (EVAP) valve. The valve can be activated using VIDA.

The evaporative emission system (EVAP) valve is close to the intake manifold.

Ignition coils

The ignition coils ignite the fuel / air mixture on command from the engine control module (ECM). The signal is re-transmitted so that the control module knows that it worked.

Each ignition coil has its own integrated power stage.

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

The ignition windings can be diagnosed by the Engine control module (ECM) and can be activated using VIDA.

Scheme 217

The emissions warning lamp in the Driver Information Module (DIM) has a warning symbol. This warning symbol varies depending on the market and model year. The warning symbols are

1. "Engine symbol" (not USA, model year 2001-)
2. "CHECK ENGINE" (MIL - Malfunction Indicator Lamp, USA only).
3. "Lambda symbol" (not USA, model year 1999-2000).

The warning symbol lights when the ignition key is turned to position II and goes out when the engine is started if the engine management system does not detect any faults.

The warning lamp is directly connected to the engine control module (ECM).

The warning lamp will light if there is a fault in one of the monitored 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 one of the following systems which affects emissions

1. gearbox control module (TCM)
2. brake control module (BCM)
3. electronic throttle module (ETM).

Scheme 218

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) as an addition to the mass air flow (MAF) sensor to calculate the injection period.

The semi-conductor sensor is grounded in the control module and is supplied with power from the control module.

The resistance in the sensor changes depending on the pressure in the intake manifold, giving a signal of 0.5 - 4.5 V. Low pressure results in low voltage, high pressure in high voltage.

The engine control module (ECM) can diagnose the manifold absolute pressure sensor. The sensor signal can be read using VIDA.

The manifold absolute pressure (MAP) sensor is on top of the radiator and is connected to the intake manifold by a hose.

Scheme 219

The fuel tank pressure sensor detects the pressure in the fuel tank. The signal from the sensor is used by the engine control module (ECM) during diagnostics to check for leakage in the fuel tank system.

The sensor, which is a piezo resistor, is grounded in the control module and supplied with power from the control module.

The resistance in the sensor changes depending on the pressure in the fuel tank, giving a signal of 0.5 - 4.5 V. Low pressure results in low voltage, high pressure in high voltage.

The tank pressure sensor can be diagnosed by the Engine control module (ECM), and the sensor's signal can be read using VIDA.

The fuel tank pressure sensor is positioned on top of the fuel tank on cars with leakage diagnostics for the evaporative emission (EVAP) system.

Scheme 220

The EVAP canister shut-off valve is used to close the connection between the EVAP canister/fuel tank system and fresh air (atmospheric pressure) when leak diagnostics are carried out on the cars with the evaporative emission (EVAP) system.

The valve is an electro-magnetic valve which is powered from the system relay. When the valve needs to be closed, it is grounded internally in the engine control module (ECM). The valve is open when in the rest position (open-circuit).

The valve can be diagnosed by the engine control module (ECM) and can be activated using VIDA.

The valve is next to the EVAP canister on cars with leak diagnostics for the evaporative emission (EVAP) system.