Part 1

Function

Start




The starter motor (6/25) is supplied with power via the starter motor relay (2/35), the starter motor relay is controlled by the engine control module (ECM) (4/46).

The start process is as follows:
1. The starter button on the Start control module (SCU) is pressed (position III).
2. A high signal (Ubat) from the start control module (SCU) (3/132) reaches the central electronic module (CEM) via LIN communication.
3. The central electronic module (CEM) (4/56) uses the button signal together with the signal from the brake light switch (3/9) and creates a start request that is transmitted to the engine control module (ECM) via CAN communication.
4. Based on the start request and the directly connected signal from the start control module (SCU), the engine control module (ECM) activates the starter motor solenoid by grounding and supplying power to the starter motor relay coil.
5. The relay closes the circuit between the starter motor solenoid and the fuse in the relay/fuse box in the engine compartment, activating the starter motor.
6. The engine control module (ECM) activates the starter motor until the engine starts (the engine speed (rpm) exceeds a certain value)

Auto start
If the starter button is released before the engine is started, the starter motor continues to run. The starter motor runs until the engine is started or until after a certain amount of time, depending on the engine coolant temperature (ECT). Low temperatures permit longer start times.
If the engine does not turn or if the engine speed is extremely low when the start relay is activated, the engine control module (ECM) interrupts start relay activation.
Activation of the starter motor is not permitted or is interrupted if:
- the engine is running (the engine speed (RPM) above a certain value)
- the immobilizer function does not allow a start. For further information also see Design and Function, Immobilizer
- the gear selector is not in position "P" or "N". The engine control module (ECM) receives a signal indicating the position of the gear selector (P/N engage/disengaged) from the transmission control module (TCM) (4/28), partially via the controller area network (CAN) and partially via a directly connected cable between the engine control module (ECM) and transmission control module (TCM). Also see Design and Function, Transmission control module (TCM).
- The brake pedal is not depressed. The signal about active/inactive brakes is received by the engine control module (ECM), partially from the directly connected stop lamp switch, partially from the brake pedal switch position, which is transmitted from the brake control module (BCM) to the engine control module (ECM).

Camshaft control (CVVT)




Only the intake camshaft can be controlled by the Engine control module (ECM) via a reset valve.
The induction camshaft is located in the engine's leading edge (in the travel direction) and the exhaust camshaft in the trailing edge (towards the passenger compartment).
The camshafts are driven by the crankshaft via a gear housing located on the engine's top side.
When each camshaft is adjusted in the factory, its position is aligned with the crankshaft's position. The camshaft's position at alignment against the crankshaft is called the camshaft's 0-position (basic setting).
At camshaft control (CVVT), the camshaft's 0-position is displaced so that the camshaft's angle position is changed. Thus, opening and closing of the exhaust and inlet valves changes relative to the crankshaft.
By controlling the camshaft's angle position, the engine's performance can be increased, idle quality can be improved, and emissions can be reduced.
The engine control module (ECM) detects the position of the camshafts by comparing the signals from the engine speed (rpm) sensor (1) (crankshaft position) and the camshaft position (CMP) sensors (2) (camshaft positions). The engine control module (ECM) then controls the angle of the camshaft by controlling the oil flow to the CVVT unit using the reset valve camshaft (3).
There are diagnostics for this function. See also: Camshaft diagnostics (CVVT), B6324S4 Camshaft Diagnostics (CVVT)

Controlling, reset valve camshaft




1. Oil filter reset valve camshaft.
2. Oil channel (pressure, inlet).
3. Channel connected with CVVT-unit's chamber (triggering).
4. Channel connected with CVVT-unit's chamber (re-triggering).
The camshaft reset valve controls the oil flow to the continuous variable valve timing (CVVT) unit. The engine control module (ECM) uses a pulse width modulation (PWM) signal to control the valve. See also: Design, B6324S4 Design
The continuous variable valve timing (CVVT) unit allows the position of the camshaft to be adjusted relative to the crankshaft.
The camshaft is secured to the CVVT-unit's rotor. The rotor (and thus, the camshaft) can rotate in relation to the timing belt pulley by the oil pressure building up on one or the other side of the rotor's vanes in the CVVT-unit.

Control occurs according to the following during deployment/return of the camshaft.




A: Inlet camshaft
- Oil pressure from the lubrication system (1) of the engine.
- The oil passes the filter for the camshaft reset valve (2) and then on to the reset valve (3).
- The engine control module (ECM) controls the oil flow to one of the CVVT unit chambers (4) depending on whether it is to be deployed/returned by the camshaft.
The reset valve is controlled by the engine control module (ECM) by high frequency, switching for deployment and return. This results in rapid and precise control. The inlet camshaft can be triggered up to approx. 40 crankshaft degrees.

Controlling the generator




The engine control module (ECM) (4/46) regulates the charge voltage of the alternator (GEN) (6/26) (via LIN communication) when requested by the central electronic module (CEM) (4/56) (via CAN communication).
The engine control module (ECM) can change the charge voltage requested by the central electronic module (CEM). to suit certain operating conditions such as engine start, idle speed or high engine load.
The value of requested charge voltage from the engine control module (ECM) and the charge current of the generator can be read off.
The alternator control module (ACM) (6/26) transmits information to the engine control module (ECM) regarding any faults. The diagnostic trouble codes (DTCs) are stored in the engine control module (ECM) in the event of a fault. In the event of certain faults, information about these faults is also transmitted to the central electronic module (CEM).
For additional information on regulating the alternator, see Design and Function, Alternator and Design and Function, central electronic module (CEM).

Variable intake system





General
Today's modern car engines often utilize systems with variable length of the intake manifolds.
In older engines with fixed lengths, the length had to be adapted to a certain specific engine speed range.
Today's system gives greater flexibility as well as additional torque without any costs in the form of, e.g., fuel consumption or emissions.
In the variable intake system, there are two actuators with associated throttles to change the length of the intake manifolds. These are:
- Actuator variable intake manifold, upper (6/139)
- Actuator variable intake manifold, lower (6/140)
The primary throttle is activated at engine speed over approx. 4800 rpm and the secondary throttle is activated between approx. 3800 rpm and 4800 rpm (applies at + 20 °C).

Different throttle combinations:
- Position 1: Both throttles are closed at engine speeds lower than approx. 3800 rpm.
- Position 2: The secondary throttle opens at approx. 3800 rpm and this shortens the length some more.
- Position 3: Both throttles are fully open to minimize the length at higher engine speeds (over 4800 rpm).
The valve for variable intake is controlled by the engine control module (ECM) (4/46).
The actuators for variable intake function can be activated and the function for variable intake can be diagnosed by the engine control module (ECM).

Oil monitoring





General
The following components are used for oil monitoring:
- oil level-/oil temperature sensor (7/166)
- engine control module (ECM) (4/46)
- driver information module (DIM) (5/1).
The sensor informs the driver via the driver information module (DIM) that the oil needs to be topped up.

Detecting the oil level
The integrated electronics of the sensor calculates the oil level using the measured value for the oil temperature.
For the correct oil level to be calculated, temporary oil level changes in the oil trough must also be included in the calculation, which can occur when driving on hills, around bends or similar for example. The engine control module (ECM) makes these calculations using the oil level sensor signal and a number of other parameters, for example, vehicle speed signal and load signal.

Controlling the cruise control (does not apply to adaptive cruise control)