Part 2

Design (Continued)

Fuel pressure sensor / fuel temperature sensor




Overview
The fuel pressure, fuel temperature sensor is combined and consists of both the fuel pressure sensor and the fuel temperature sensor. The sensor detects the fuel pressure (the absolute pressure) and the temperature of the fuel in the fuel rail.
The fuel pressure sensor is located on the fuel rail's end.
The fuel pressure-/fuel temperature sensor can be diagnosed by the engine control module (ECM) and its signals (pressure and temperature) can be read off.
Fuel pressure sensor
The pressure sensor is a Piezo resistive type resistor, the resistance of which changes with the pressure. Depending on the pressure in the fuel rail, an analog signal of 0 - 5 V is transmitted to the engine control module (ECM). Low pressure results in low voltage, high pressure gives high voltage.
The engine control module (ECM) then uses this signal to adjust the pressure in the fuel rail using the fuel pump control module.
The pressure sensor is supplied with 5 V and grounded in the engine control module (ECM). The pressure sensor transmits a signal indicating the fuel pressure to the engine control module (ECM) on a separate cable.

Note! The absolute pressure is displayed when using parameter read outs to read off the fuel pressure. If there is no pressure at the fuel rail, the atmospheric pressure will be displayed.

Hint: The relative pressure (absolute pressure minus atmospheric pressure) is displayed when reading off the fuel pressure via a manometer connected to the fuel rail.

Fuel temperature sensor
The temperature sensor is an NTC sensor. The sensor is supplied with voltage (signal) from and grounded in the engine control module (ECM).
The resistance in the sensor changes according to the temperature of the fuel. This provides the engine control module (ECM) with a signal of between 0 - 5 V. Low temperature results in high voltage (high resistance). High temperature results in low voltage (low resistance).
The engine control module (ECM) uses the signal to calculate the volume of the fuel.

Oil level and oil temperature sensor




The sensor is a combined oil level and oil temperature sensor. The function of the sensor is to provide the engine control module (ECM) with information about the level and temperature of the engine oil in the oil trough.
The sensor consists of:
- a terminal with three pins
- integrated electronics
- 2 capacitive gauge elements
- a PTC resistor.
The sensor is supplied with 5 V from the engine control module (ECM) and generates a pulse width modulation (PWM) signal to the engine control module (ECM).
The engine control module (ECM) can diagnose the sensor.

Main relay (system relay)




The function of the main relay (system relay) is to supply certain components with voltage.
The relay is mechanical and has a closing and opening function. In the rest position the circuit in the relay is open.
The main relay terminals (#30 and #86) are supplied with voltage by the battery. When the starter button on the start control module (SCU) has been activated and the engine control module (ECM) is powered, the terminal (#85) on the main relay is grounded by the engine control module (ECM).
When the terminal (#85) is grounded, the relay is activated and a number of components are powered via the relay terminal (#87).
The main relay is in the integrated relay/fuse box in the engine compartment and is diagnosed by the engine control module (ECM).

Fuel injectors




The function of the injectors is to spray fuel into the cylinders in the correct spray patterns. This happens sequentially.
The injectors are located along the intake pipe.
The engine control module (ECM) controls the injectors by grounding the valves in pulses.
The injectors can be diagnosed by the engine control module (ECM) and can be activated.

Ignition coils




The ignition coils supply the spark plugs with high voltage to produce sparks. The engine control module (ECM) controls the ignition coils so that sparks are generated at the correct time. The signal reconnects to the engine control module (ECM) so that diagnostics can be carried out.
Each ignition coil has an integrated power stage.
The ignition coils are in the sparkplug wells above each spark plug.
The control module checks the ignition coils' function using one separate diagnostic lead.

Camshaft reset valve (CVVT)




The camshaft reset valve controls the oil flow to the CVVT unit (camshaft pulley).
The valve consists of an electro-magnetic valve with a spring-loaded piston. There are slits in the piston which channel the engine lubricating oil to the CVVT unit by moving the piston in the reset valve. The continuous variable valve timing (CVVT) unit turns the camshaft (the camshaft timing changes). The direction in which the camshaft turns depends on the chamber in the CVVT unit which is supplied with oil (pressure).
An oil filter is mounted at the intake channel for the valves to prevent oil contaminants from affecting the function of the reset valves.
The system relay supplies the reset valve with voltage via a fuse. The valve is grounded (control stage) internally in the engine control module (ECM). When the valve is grounded using a pulse width modulation (PWM) signal, the oil flow in the valve can be regulated to the different chambers in the continuous variable valve timing (CVVT) unit at variable rates. This allows the angle position to be changed precisely and steplessly.
The engine control module (ECM) can diagnose the camshaft reset valve.
The valve is located on the cylinder head above the camshaft. There is a valve for intake camshaft.
There is no valve for the exhaust camshaft.

Evaporative emission system (EVAP) valve




The evaporative emission system (EVAP) valve is used to open and close the connection between the EVAP canister and the intake manifold. The valve controls the flow of hydro-carbons (fuel vapor) from the EVAP canister to the engine intake manifold using the vacuum in the intake manifold. This ensures that hydro-carbons stored in the EVAP canister are used in the engine combustion process.
The valve is an electromagnetic valve and is powered from the system relay. When the valve needs to be opened, it is grounded internally in the engine control module (ECM). The evaporative emission system (EVAP) valve is closed when in the standby position (open-circuit).
When the control module requests that the EVAP canister should be drained (the hydrocarbons stored in the canister should be released into the engine), the control module deploys the evaporative emission system (EVAP) valve by grounding it. A pulse width modulation (PWM) signal is used to ground the valve and to control the degree to which the valve will open. In this way, the drainage of the EVAP canister is matched to the volumetric efficiency of the EVAP canister, the engine speed (rpm) and the engine load.
The evaporative emission system (EVAP) valve can be diagnosed by the engine control module (ECM) and can be activated.
The EVAP-valve is located under the manifold (on the front of the engine).

Leak diagnostic unit (certain markets only)




The leakage diagnostic unit's function is to pressurize the tank system for leakage diagnostics.

The leak diagnostic unit consists of a plastic housing with:
1. electrical air pump
2. a valve / solenoid which governs the air flow in the unit
3. a heater element (PTC resistor) which warms up the pump.
The electrical pump, valve and heater element in the unit are supplied with voltage by the system relay. The pump, valve and heater element are grounded (control) in the engine control module (ECM).
When leakage diagnostics is not active, the valve is kept open to ambient air so that EVAP-control can be performed.
At leakage diagnosis, the pump in the leakage diagnostic unit will start, and the valve in the leakage diagnostic unit will be controlled by Engine control module (ECM) by grounding the various circuits internally in Engine control module (ECM).
Engine control module (ECM) checks sealing in the fuel tank system by pressurizing the system and at the same time monitor a number of relevant parameters. See also: Leak diagnostics (certain markets only), B6304T4 Leak Diagnostics (Certain Markets Only)
The engine control module (ECM) can diagnose the leak diagnostic unit.
The valve in the leakage diagnostic unit can be activated.
The leak diagnostic unit is at the upper front edge of the fuel tank.

air conditioning (A/C) compressor.




The air conditioning (A/C) compressor transports refrigerant, which is necessary for air conditioning (A/C) operation. It is an axial piston compressor with variable displacement. I.E. The compressor has adjustable cylinder displacement which is controlled by a check valve (solenoid). The valve, which is underneath the compressor, can be replaced.
The A/C compressor is mounted on the cylinder block and is driven by the engine's crankshaft via the auxiliaries belt.
For further information, see Design and Function, climate control module (CCM).

Air conditioning (A/C) relay




The air conditioning (A/C) relay supplies the A/C compressor with voltage. The relay is controlled by the engine control module (ECM) based on information from different signals:
- the climate control module (CCM) (via the control area network (CAN))
- the engine coolant temperature
- the position of the accelerator pedal (AP)
- the pressure in the system.
The engine control module (ECM) can temporarily disengage the A/C compressor during wide open throttle (WOT) acceleration.
The relay is mechanical. It has a closing / opening function and is supplied with power from the system relay.
In the rest position the circuit in the relay is open.
The system relay supplies the coil and the relay with power. The relay activates when the coil is grounded in the engine control module (ECM), the circuit closes and the A/C compressor is supplied with power via the relay voltage output.
The relay coil is grounded (signal) when the engine control module (ECM) receives a signal via the CAN network from the climate control module (CCM) to activate the relay and start the compressor.

Starter motor relay




The function of the starter motor relay is to supply power to the starter motor.
The starter motor relay is in the relay/fusebox in the engine compartment.

Engine cooling fan (FC) / engine cooling fan (FC) control module





Note! The engine cooling fan may have a post-run of up to approx. 6 minutes after the engine has been turned off. The time for the fan's post-run depends on engine temperature, temperature in the engine compartment and pressure level in the A/C-system.

Warning! Be careful since the engine cooling fan may have a post-run after the engine has been turned off.

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

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

The engine cooling fan (FC) has two functions. One is to cool the engine compartment, the other is to cool the condenser when the air conditioning (A/C) compressor is working.
The engine control module (ECM) transmits a pulse width modulated (PWM) signal to the engine cooling fan (FC) control modules. The control modules then activate the fans at different speeds. The speed is determined by the engine control module (ECM), depending on the coolant temperature and the vehicle speed.
The temperature conditions for engagement of the different engine cooling fan (FC) stages may vary slightly, depending on the engine variant and the equipment level. The temperature conditions apply when:
- the A/C is off
- no faults are detected by the engine control module (ECM).
The engine cooling fan (FC) is located behind the radiator and its control module is grounded and powered with battery voltage via a fuse.
There are diagnostics for the engine cooling fan (FC). The engine cooling fan (FC) transmits a diagnostic signal to the engine control module (ECM).

Fuel pump




The fuel pump consists of:





The function of the fuel pump is to ensure that the correct pressure and glow is maintained at the fuel rail on the request of the engine control module (ECM).
The fuel pump is electrically powered via the Pump Electronic Module (PEM) with variable outputs to supply varying fuel pressure/flow and is grounded in the body via the fuel pump control module.
The engine control module (ECM) can diagnose the fuel pump function for the correct pressure and electric open circuit. The fuel pump control module is diagnosed by Engine control module (ECM). See also: Fuel pressure control, diagnostics, B6304T4 Fuel Pressure Control, Diagnostics
The fuel pump can be activated and its status read off using the diagnostic tool.
The pressure in the fuel rail can be measured by connecting a manometer to a service nipple. This nipple is on the right-hand end of the fuel rail.

Fuel pump control module




The fuel pump control module is called the PEM (Pump Electronic Module). The function of the PEM is to supply the fuel pump with voltage and to control the power output of the fuel pump. When the power output of the pump is changed the fuel pressure/fuel flow is also changed.
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.
Fuel pump control module is controlled by Engine control module (ECM) via serial communication. Then the fuel pump control module controls the fuel pump by adding a pulse-width modulated (PWM) voltage on the fuel pump's ground cable.
This means that the voltage across the pump changes, and then also the fuel pump's output.
See also
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 control, diagnostics, B6304T4 Fuel Pressure Control, Diagnostics
The pulse width modulated (PWM) signal from the engine control module (ECM) to the fuel pump control module can be read off using the diagnostic tool.
The fuel pump control module is on the outside on the right-hand side of the fuel tank.

Emissions warning lamp




The emissions warning lamp in the Driver Information Module (DIM) has a warning symbol. This warning symbol varies depending on the market. The warning symbols are:
- Engine symbol" (not USA)
- "CHECK ENGINE" (MIL - Malfunction Indicator Lamp, only USA)
The warning lamp lights when the start control module (SCU) is activated to position II. The warning lamp will go out after approximately 15 seconds or if the engine is started when no fault is found in the engine management system.
If Readiness is not complete (certain diagnostic functions not completed), the warning lamp will flash instead of going out when the start control module (SCU) is in position II.
The warning lamp will light if there is a fault in one of the parameters in the engine management system. The warning lamp will also light in response to a request transmitted via the control area network (CAN) if there is a fault in the transmission control module (TCM) which affects emissions.

Electronic throttle unit




The electronic throttle unit, using the PWM control signal from the engine control module (ECM), regulates the amount of air for engine combustion. This is done using an electronically controlled shutter.
The aluminium electronic throttle unit consists of a round throttle disc on a spindle. The spindle is driven by a DC motor (damper motor), gear wheel and two springs; one for opening and one for return.
By changing the polarity of the power supply, the DC motor can be run in both directions. At one of the limit positions the throttle disc is closed so that minimal air can pass the throttle unit. In the other limit position, the throttle disc is parallel to the air flow. This provides maximum airflow through the electronic throttle unit.
Two permanent magnets in the gear sector on the throttle spindle are used to check the position of the throttle disc. The permanent magnets affect two throttle position (TP) Hall sensors in the cover. The analog signals from the two sensors are transmitted to the engine control module (ECM). The signals are offset. The engine control module (ECM) compares these signals with the stored desired values to check if they are plausible.
The electronic throttle unit is located on the engine intake manifold. In the event of a fault, the throttle unit must be replaced as a single unit.
The engine control module (ECM) can diagnose the electronic throttle unit.

Throttle position (TP) sensor
See Design, Electronic throttle unit.