Part 3

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 engine control module (ECM) can diagnose the ignition coils.

Camshaft reset valve (Continuous variable valve timing (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). See also: Function, B8444S Function
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) 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 cam timing to be changed precisely and steplessly.
It is important not to mix up the pipes for the valves when removing/installing the reset valve camshaft.
The engine control module (ECM) can diagnose the camshaft reset valve.
The valves are on the cylinder head above the camshafts. There are four reset valves, two for the inlet camshaft and two 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 evaporative emission system (EVAP) valve is on the rear edge of the engine (passenger compartment side).

Leak diagnostic unit (certain markets only)




The function of the leak diagnostic unit is to pressurize the fuel tank system during leak 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 leak diagnostics are not active, the valve is held open to ambient air for EVAP control to be carried out.
During leak diagnostics the pump in the leak diagnostic unit starts. The valve in the unit is operated by the engine control module (ECM) by grounding the different circuits internally in the engine control module (ECM).
The Engine control module (ECM) checks the fuel tanks system for leaks by pressurizing the system and at the same time monitoring a number of relevant parameters. Also see: Leak diagnostics (certain markets only) Leak Diagnostics (Certain Markets Only)
The engine control module (ECM) can diagnose the leak diagnostic unit.
The valve in the leak diagnostic unit can be activated.
The leak diagnostic unit is at the upper front edge of the fuel tank.

Air conditioning (A/C) compressor (check valve 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 air conditioning (A/C) compressor is directly mounted on the engine block and is powered by the engine crankshaft via the auxiliaries belt. For further information, see Climate control and 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 Controller area network (CAN) 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. See also: Function, B8444S Function
The starter motor relay is in the relay/fuse box 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 AC-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) cools the coolant, engine compartment and the condenser when the air conditioning (A/C) compressor is running.
The engine control module (ECM) transmits a pulse width modulated (PWM) signal to the engine cooling fan (FC) control module. The control module then activates the fan at different speeds. The speed of the engine cooling fan (FC) is determined by the engine control module (ECM), depending on the coolant temperature (based on the signal from the engine coolant temperature (ECT) sensor) 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).
There is an internal diagnostic function in the engine cooling fan (FC). This function transmits a signal to the engine control module (ECM) if the fan is partially or fully blocked. To do this, the engine cooling fan (FC) control module grounds the pulse width modulation (PWM) signal based on a predetermined pattern.
The engine cooling fan (FC) and its control module are behind the radiator.
The engine cooling fan (FC) can be diagnosed by the engine control module (ECM) and can be activated.

Fuel pump




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 Fuel Pressure Regulation, Diagnostics
The fuel pump can be activated and its status can be read off.
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.

Fuel pump (FP) control module




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 (FP) control module is supplied with battery voltage by the fuel pump relay and grounded in the car body. The fuel pump relay is controlled by the central electronic module (CEM) at the request of 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: Function, B8444S Function
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 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 off.
The fuel pump control module is on the outside on the right-hand side of the fuel tank.

Valve variable intake




The valve for variable intake controls the vacuum motor for the damper in the variable intake manifold.
The valve consists of an electro-magnetic valve which controls the air flow between the vacuum tank and the vacuum valve for the damper in the variable intake manifold.
The valve is supplied with voltage from the system relay via fuse and ground (control) internally in the engine control module (ECM). Also see: Function, B8444S Function
The valve for variable intake can be diagnosed by the engine control module (ECM).
The valve for variable intake is on the right-hand side of the engine beside the intake manifold.

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, USA only).
The warning lamp lights when the ignition key is turned 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 ignition key 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 aluminum 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.