Description of the electronic engine management system controller (ECM)
The ECM communicates with many other emission control components and systems and checks their condition. OBD II diagnostic monitors system operation and sets a diagnostic trouble code (DTC), if it gets worse.
The operation of the MILs and the storage of DTCs depend on the type of DTC. Emissions DTCs are classified as Type A or Type B codes. Type C codes do not apply to emissions.
The ECM is located in the engine compartment. The ECM is the control center of the engine control system. The ECM controls the following components:
- fuel injection system
- Ignition system
- Emission control systems
- Onboard diagnostic system
- Air conditioning and fans
- Throttle Actuator Control System (TAC)
The ECM constantly monitors information from various sensors and other sources, and monitors systems that affect vehicle performance and emissions. The ECM also performs diagnostic checks on various parts of the system. The ECM is able to recognize performance issues and notify the driver through the Malfunction Indicator Lamps. If the ECM detects a problem, it sets a DTC. The area to which the fault belongs can be determined by the specific DTC. This helps the technician when performing repairs.
ECM Operation
The ECM can supply 5V or 12V to various sensors and switches. This is done with resistors pulling up the appropriate lines to the stabilized power lines inside the ECM. In some cases, a conventional serial voltmeter does not allow an accurate measurement due to the low internal resistance. Therefore, to accurately measure voltages, a digital multimeter with an input impedance of at least 10 MΩ is required.
The ECM controls the output circuits by applying ground potential or supply voltage through the so-called. output shapers.
EEPROM
Electrically erasable programmable read-only memory (EEPROM) is a non-volatile storage device that is part of the ECM. The EEPROM stores the programming and calibration information that the ECM needs to control the power circuits.
ECM reprogramming requires special hardware and appropriate programs and calibration data.
Programming the anti-theft frequency code
The vehicle is equipped with an anti-theft system that communicates with the ECM. If the ECM is replaced, the frequency code of the vehicle's anti-theft module must be programmed into the new ECM. Without this procedure, the car will not start.
Knock sensor module
The ECM continuously monitors the status of the knock control evaluation circuit using an onboard integrated circuit. knock sensor module (KS) contains electronic circuitry that allows the ECM to analyze the knock sensor signals and diagnose the knock sensors and related circuits. If the ECM detects that the knock sensor module is not reading these signals, the DTC will set.
Diagnostic block
Diagnostic connector (DLC) is a 16-pin connector through which the technician can read serial data for diagnostic purposes. By connecting a scan tool to this connector, the technician can monitor various serial data link parameters and display diagnostic trouble code information. The DLC connector is located in the driver's compartment, under the dashboard.
Malfunction indicator lamp
The Malfunction Indicator Lamp is located inside the instrument panel. The Malfunction Indicator Lamp (MIL) is controlled by the ECM and illuminates when the ECM detects a condition that affects vehicle emissions.
ECM Maintenance Precautions
The ECM is designed to handle normal load currents that are generated during vehicle operation. However, overloading these circuits should be avoided. When testing for an open circuit or short circuit, do not ground or apply voltage to any ECM circuits unless directed to do so. Such circuits can only be tested with a digital multimeter.
Aftersales (additional) electrical and vacuum equipment.
Note: Vacuum driven accessories are not allowed to be connected to this vehicle. Installing vacuum-operated accessories can damage vehicle components or systems.
Note: Additional electrical equipment must be connected to the on-board network near the battery to avoid damage to the vehicle (both food and mass).
aftersales (additional) electrical and vacuum equipment is any equipment fitted to a vehicle after leaving the factory that is connected to the vehicle's electrical or vacuum system. The design of the car does not provide any reserves for the installation of such equipment.
Additional electrical equipment, even if installed in accordance with these strict requirements, can cause problems with the vehicle's electrical system. This may also apply to equipment not connected to the vehicle's electrical system, such as portable phones and radios. Thus, the first step in diagnosing any problems with the on-board network is to remove all aftermarket electrical equipment from the car. If after that the problem remains, its diagnosis is carried out in the usual manner.
Damage from static electricity
Important: To avoid electrostatic damage to the ECM, DO NOT touch the ECM connector pins.
Electronic components used in control systems are often designed for very low voltages. Electronic components are easily damaged by electrostatic discharge. To damage some electronic components, an electrostatic voltage of less than 100 V is sufficient. For comparison, for a person to only feel an electrostatic discharge, a voltage of 4000 V is needed.
A person can acquire an electrostatic charge in different ways. The most typical are electrification by friction and electrostatic induction. For example, frictional electrification can occur when a person slides into a car seat.
Electrification by electrostatic induction occurs when a person wearing well-insulated shoes, while standing next to a highly charged object, momentarily touches ground. Charges of the same name flow to the ground, and the person remains charged with a charge of opposite polarity. Electrostatic charge can cause damage to electronic components, so it is important to be careful when handling and checking.
Inspection of devices under the hood
Important: This check is very important and must be carried out carefully and carefully.
Carefully inspect under the hood devices when performing any diagnostic procedure or when diagnosing the cause of an emissions test failure. This often allows you to fix the problem without any additional steps. When checking, observe the following rules:
- Inspect vacuum hoses - correct wiring, pinches, cuts, disconnections.
- Inspect hard-to-reach hoses.
- Inspect the wires in the engine compartment for the following faults:
- Burnt or worn areas
- Pinched wires
- Touching sharp edges
- Touching hot exhaust pipes
Required basic knowledge
Note: Failure to understand the basic principles of this electrical system when performing diagnostic procedures may result in misdiagnosis or damage to electrical system components. Without such basic knowledge, one should not try to diagnose electrical system problems.
To effectively use this section of the Maintenance Manual, basic hand tool skills are required.
To use this section of the service manual, you must be familiar with some basic engine operation and electrical diagnostics.
- Basics of electrical circuits - You need to know the basics of electricity and understand what voltage, current and resistance are. You need to understand what happens to an electrical circuit when it breaks or shorts, and you need to be able to determine a shorted or broken circuit with a digital multimeter. Must be able to read and understand electrical schematics.
- Using a Digital Multimeter - One must be able to work with a digital multimeter - an extremely valuable instrument. You need to be able to measure the voltage with a multimeter (IN), resistance (Ohm), current (A), variable signals (min/max) and frequency (Hz).
- Using Circuit Testers - Do not use a test lamp to test engine controls unless specifically directed to do so. You must be able to use jumpers to test components and a digital multimeter without damaging the contacts. You should be familiar with the use of the J 35616 connector test adapter kit and use this kit whenever diagnostic procedures require connection to the pin side of the connector.
Description of throttle actuator control system (TAC)
Throttle Actuator Control System (TAC) used to improve emissions, fuel economy and improve overall handling characteristics. Throttle Actuator Control System (TAC) eliminates the mechanical connection between the accelerator pedal and the throttle. Throttle Actuator Control System (TAC) eliminates the need for an automatic cruise control system and an idle air control motor. The following is a list of components of the throttle actuator control system (TAC):
- The accelerator pedal assembly includes the following components:
- Accelerator pedal.
- Accelerator pedal position sensor 1 (APP).
- Sensor 2 APP.
- The throttle body assembly includes the following components:
- Throttle angle sensor 1 (TP)
- Throttle Angle Sensor 2 (TP)
- Throttle actuator motor
- throttle valve
- ECM controller
The ECM monitors the driver's acceleration requirement using 2 APP sensors. The voltage range of the APP sensor 1 is approximately 0.98 to 4.16 volts, changing as the accelerator pedal moves from the initial position of the pedal not depressed to the position of the pedal fully depressed. The range of the APP sensor 2 is approximately 0.49 to 2.08 volts, changing as the accelerator pedal moves from the initial position of the pedal not depressed to the position of the pedal fully depressed. The ECM processes this information along with other sensor inputs to command the throttle to a certain position.
The throttle valve is controlled by a DC motor called the throttle motor. The ECM can drive this engine forward or reverse by controlling battery voltage and/or ground on the 2 built-in drivers. The throttle is held at its 7% rest position by a constant force return spring. When the throttle motor is not energized, this spring holds the throttle in its original position.
The ECM monitors the throttle angle using 2 TP sensors. TP sensor 1 voltage varies from approximately 0.5 to 4.25 volts when the throttle is moved from "0 percent" to wide open throttle (WOT). TP sensor 2 voltage changes from approximately 4.45 to 0.7 volts when the throttle is moved from "0 percent" to wide open throttle (WOT).
The ECM performs a diagnostic that checks the voltage levels of both APP sensors, both TP sensors, and the throttle actuator motor circuit. It also controls the return speed through the action of both return springs, which are housed inside the throttle body assembly. This diagnostic runs at different times depending on whether the engine is running or not running and whether the ECM is in the process of detecting throttle parameters.
Each time the ignition is turned on, the ECM performs a quick throttle return spring test to verify that the throttle can return to the 7 percent home position from the 0 percent position. This is to ensure that the throttle can be returned to its original position in the event of a drive motor circuit failure. Note that at low temperatures, the ECM will move the throttle by 7% with the ignition on and the engine off to remove any ice that may have formed on the throttle.
Throttle valve re-sizing procedure
The ECM remembers a number of parameters, including the smallest throttle position (0%), initial position (7%) and the return rate of both springs. These values are only cleared or overwritten when the ECM is reprogrammed or when the Throttle Reset procedure is performed. Note that if the battery is disconnected, the ECM will perform a throttle relearn procedure immediately after the ignition is turned on.
The throttle reset procedure is performed each time the ignition is turned on if the engine has been off for more than 29 seconds and the following conditions are met:
- Engine speed is less than 40 rpm.
- Vehicle speed is 0 km/h (0 mph).
- Engine coolant temperature (ECT) is within 5-85°C (41-185°F).
- Intake air temperature is between 5-60°C (41-140°F).
- The signal of the accelerator pedal position sensor corresponds to an angle of less than 14.9%.
- Ignition voltage 1 is greater than 10 volts.
After 29 seconds, the ECM moves the throttle plate from its original position to fully closed, then to approximately 10% open. This procedure takes about 6-8 seconds. If any malfunction occurs in the throttle control mechanism (TAC) a diagnostic trouble code is set (DTC). The scan tool's TAC Learn Counter should be 0 at the beginning of the procedure and should increase to 11 by the time the procedure is completed. If the counter does not start at 0 or end at 11, this indicates a problem; DTC must be written.
TAC System Default Actions/Low Power Modes
The ECM has 2 low power modes that it can enter if a malfunction is detected in the throttle position control system. If an accelerator position sensor 1 circuit or APP sensor 2 circuit, throttle position sensor 2 circuit, or throttle position sensor 1 circuit malfunction is detected at a certain accelerator pedal position, the ECM will go into one of two low power modes. In this mode, the engine torque is limited so that the vehicle cannot accelerate faster than 100 km/h (60 mph). The ECM remains in this low power mode for the duration of the ignition cycle, even if the fault is corrected.
If there is a malfunction in the throttle position control circuits, a discrepancy between the prescribed and actual throttle position, a return spring test failure, or a TP 1 sensor circuit malfunction, the ECM will enter another low power mode. In this mode, engine speed is limited to 2500 rpm and 3-6 randomly selected fuel injectors are turned off. In this case, a command is given to turn on the low power indicator. The ECM remains in this low power mode for the duration of the ignition cycle, even if the fault is corrected. Note that if a TP 1 sensor or throttle position control circuit malfunction is observed while the engine is idling without depressing the accelerator pedal, the engine may stall.
Description of the camshaft position control system
The camshaft position control system allows the ECM to change the valve timing of all 4 camshafts while the engine is running. Camshaft Position Actuator Assembly (15) changes the position of the camshaft in accordance with changes in oil pressure. The camshaft position actuator solenoid valve changes the oil pressure by adjusting the advance or retard of the camshaft. Changing the valve timing when changing the fuel consumption of the engine allows you to improve the following parameters:
- Engine output
- Fuel consumption
- Emission reduction
Solenoid valve (7) The camshaft position control system is controlled by the ECM. Changing the positions of the camshafts is controlled by a crankshaft position sensor (CKP) and camshaft position sensors (CMP). The ECM uses the following information to calculate the desired camshaft positions:
- Engine coolant temperature sensor signal (EATING)
- Estimated engine oil temperature (EOT)
- Mass air flow sensor signal (MAF)
- Throttle Angle Sensor Signal (TP)
- Vehicle speed sensor signal (VSS)
- Filling ratio
Job
The camshaft position actuator assembly is located in the outer housing and is driven by the timing chain. The assembly has a fixed vane rotor mounted on the camshaft. The oil pressure on the fixed vanes causes the corresponding camshaft to rotate relative to the crankshaft. The movement of the intake camshafts allows you to set the advance of the intake valves up to 50 degrees of the crankshaft. The movement of the exhaust camshafts allows you to set the delay of the exhaust valves up to 50 degrees of the crankshaft. When oil pressure is applied to the back of the vanes, the camshafts return to 0 degrees crankshaft or top dead center (TDC). The ECM commands the camshaft position control solenoid to move the solenoid plunger and spool valve to direct oil into the advance port (11). Oil flowing through the camshaft position actuator from the solenoid advance passage creates pressure on the vane advance side of the camshaft position actuator assembly. When the camshaft position is retarded, the camshaft position control solenoid valve directs oil to the camshaft position actuator through the delay channel (3). The ECM can also command the camshaft position actuator solenoid valve to cut off oil flow to both channels to fix the current camshaft position.
The ECM controls the camshaft position control solenoid valve by applying a PWM control signal to the solenoid coil. The greater the duty cycle of the pulse-width signal, the greater the change in the valve timing of the camshaft. The camshaft position control actuator also has a locking pin (14), which prevents the mutual movement of the outer casing and the impeller assembly. Before the camshaft position actuator can move, the lock pin must be released by oil pressure. The ECM constantly compares the signals from the camshaft position sensors with the signal from the crankshaft position sensor to detect camshaft positions and troubleshoot the system. If there is a malfunction in the intake or exhaust camshaft position actuator, the opposite bank intake or exhaust camshaft position actuator is set to the default position of 0 degrees crankshaft.
Operation of the camshaft position control system
| Movement state | Changing the position of the camshaft | Target | Result |
| Idling | Without change | Valve overlap minimization | Idle speed stabilization |
| Light engine load | Valve delay | Valve overlap reduction | Engine power output stabilization |
| Average engine load | valve timing | Increased valve overlap | Fuel economy and emission reduction |
| Low or medium rpm under heavy load | valve timing | Inlet valve closing advance | Torque increase at low and medium speeds |
| High RPM under heavy load | Valve delay | Intake valve closing delay | Engine output boost |