Part 3

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 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) 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. See also: Function Function
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: Due to there being various engine cooling fan suppliers, there are engine cooling fan versions consisting 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 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) has diagnostics for the fuel pump function to check for correct pressure and electrical open-circuits. The engine control module (ECM) can also diagnose the fuel pump control module. Also see Fuel pressure regulation, diagnostics Fuel Pressure Regulation, 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 PEM (Pump Electronic Module). It 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: Function 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 using the diagnostic tool.
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 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 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.