Main Component of Engine Control System General

The main components of the 2GR-FE engine control system are as follows:

Components

Outline

Quantity

Function

ECM

32-bit CPU

1

The ECM optimally controls the SFI ESA and ISC to suit the operating conditions of the engine in accordance with the signals provided by the sensors.

Oxygen Sensor (Bank 1, Sensor 2) (Bank 2, Sensor 2)

Cup Type with Heater

2

This sensor detects the oxygen concentration in the exhaust emission by measuring the electromotive force which is generated in the sensor itself.

The basic construction and operation of this sensor are the same as in the 2AZ-FE engine. For details, see page EG-47.

Air Fuel Ratio Sensor (Bank 1, Sensor 1) (Bank 2, Sensor 1)

Planar Type with Heater

2

As with the oxygen sensor, this sensor detects the oxygen concentration in the exhaust emission. However, it detects the oxygen concentration in the exhaust emission linearly. The basic construction and operation of this sensor are the same as in the 2AZ-FE engine. For details, see page EG-47.

Mass Air Flow Meter

Hot-wire Type

1

This sensor has a built-in hot-wire to directly detect the intake air mass.

The basic construction and operation of this meter are the same as in the 2AZ-FE engine. For details, see page EG-40.

Crankshaft Position Sensor (Rotor Teeth)

Pick-up Coil Type (36-2)

1

This sensor detects the engine speed and performs the cylinder identification.

Intake VVT Sensor LH, RH (Rotor Teeth)

MRE Type (3)

2

This sensor performs the cylinder identification.

Exhaust VVT Sensor LH, RH (Rotor Teeth)

MRE Type (3)

2

This sensor performs the cylinder identification.

Engine Coolant Temperature Sensor

Thermistor Type

1

This sensor detects the engine coolant temperature by means of an internal thermistor.

Intake Air Temperature Sensor

Thermistor Type

1

This sensor detects the intake air temperature by means of an internal thermistor.

Knock Sensor 1,2

Built-in Piezoelectric Type (Flat Type)

2

This sensor detects an occurrence of the engine knocking indirectly from the vibration of the cylinder block caused by the occurrence of engine knocking.

Throttle Position Sensor

No-contact Type

1

This sensor detects the throttle valve opening angle.

The basic construction and operation of this sensor are the same as in the 2AZ-FE engine. For details, see page EG-44.

Accelerator Pedal Position Sensor

No-contact Type

1

This sensor detects the amount of pedal effort applied to the accelerator pedal. The basic construction and operation of this sensor are the same as in the 2AZ-FE engine. For details, see page EG-42.

Injector

12-Hole Type

6

The injector is an electromagnetically-operated nozzle which injects fuel in accordance with signals from the ECM.

Crankshaft Position Sensor

The timing rotor of the crankshaft consists of 34 teeth, with 2 teeth missing. The crankshaft position sensor outputs the crankshaft rotation signals every 10", and the missing teeth are used to determine the top-dead-center.

Toyota Surf Timing Control System
Timing Rotor

NE Signal Plate (72G- CA)

NE Signal Plate (72G- CA)

Crankshaft Position Sensor Missing Tooth

2 Teeth Missing

Crankshaft Position Sensor

2 Teeth Missing

Intake and Exhaust VVT Sensors 1) General

The MRE (Magnetic Resistance Element) type intake and exhaust VVT sensors are used. To detect the camshaft position, a timing rotor that is secured to the camshaft in front of the VVT controller is used to generate 6 (3 Hi Output, 3 Lo Output) pulses for every 2 revolutions of the crankshaft.

285EG79

279EG5G

Intake VVT Sensor RH Exhaust VVT Sensor RH

Intake VVT Sensor RH Exhaust VVT Sensor RH

Vvt Sensor 2az

Intake VVT Sensor (Right Bank) Exhaust VVT Sensor (Right Bank)

285EG82 285EG83

Intake VVT Sensor (Right Bank) Exhaust VVT Sensor (Right Bank)

285EG82 285EG83

VVT Sensor Signal Plate (720- CA)

VVT Sensor

18G- CA

18G- CA

12G- CA

12G- CA

Crankshaft

Position

Sensor

Crankshaft

Position

Sensor

285EG84

285EG84

2) MRE Type VVT Sensor

The MRE type VVT sensor consists of an MRE, a magnet and a sensor. The direction of the magnetic field changes due to the different shapes (protruded and non-protruded portions) of the timing rotor, which passes by the sensor. As a result, the resistance of the MRE changes, and the output voltage to the ECM changes to Hi or Lo. The ECM detects the camshaft position based on this output voltage.

The differences between the MRE type VVT sensor and the pickup coil type VVT sensor used on the conventional model are as follows.

Item

Sensor Type

MRE

Pick-up Coil

Signal Output

Constant digital output starts from low engine speeds.

Analog output changes with the engine speed.

Camshaft Position Detection

Detection is made by comparing the NE signals with the Hi/Lo output switch timing due to the protruded/non-protruded portions of the timing rotor, or made based on the number of the input NE signals during Hi/Lo outputs.

Detection is made by comparing the NE signals with the change of waveform that is output when the protruded portion of the timing rotor passes.

Timing Rotor

Timing Rotor

Pick Coil Wave Form

Intake VVT Sensor RH

^ MRE Type and Pick-up Coil Type Output Waveform Image Comparison '

271EG160

Engine Speed

Sensor Output

Engine Speed

Digital Output

Sensor Output

Engine Speed

Sensor Output

Analog Speed Sensor Wave Form
Analog Output

MRE Type

Pick-up Coil Type

232CH41

Throttle Position Sensor

The no-contact type throttle position sensor uses a Hall IC, which is mounted on the throttle body.

The Hall IC is surrounded by a magnetic yoke. The Hall IC converts the changes that occur in the magnetic flux at that time into electrical signals and outputs them in the form of a throttle valve effort to the ECM.

The Hall IC contains circuits for the main and sub signals. It converts the throttle valve opening angles into electric signals with two differing characteristics and outputs them to the ECM.

Throttle Body

Throttle Position Sensor Portion

Throttle Body

Throttle Position Sensor Portion

Throttle Body Section

Hall IC

(for Throttle Position Sensor) Magnet

Cross Section

View from A

Magnet

Hall IC

(for Throttle Position Sensor) Magnet

Cross Section

Throttle Position Sensor

Magnet

Hall IC

Hall IC

VTA1

VCTA

VTA2

Magnet

Output 3 Voltage 2

VTA2

VTA1

1G 2G 3G

4G 5G BG 7G 8G

9G

Throttle Valve Fully Open

Throttle Valve Fully Close

Throttle Valve Fully Open

Throttle Valve Opening Angle

Service Tip

The inspection method differs from the conventional throttle position sensor because this sensor uses a Hall IC. For details, refer to the 2007 Camry Repair Manual (Pub. No. RM0250U).

G25EG13TE

23GLX12

238EG79

Knock Sensor (Flat Type) 1) General

In the conventional type knock sensor (resonant type), a vibration plate, which has the same resonance point as the knocking frequency of the engine, is built in and can detect the vibration in this frequency band.

On the other hand, a flat type knock sensor (non-resonant type) has the ability to detect vibration in a wider frequency band from about 6 kHz to 15 kHz, and has the following features:

The engine knocking frequency will change a bit depending on the engine speed. The flat type knock sensor can detect vibration even when the engine knocking frequency is changed. Thus the vibration detection ability is increased compared to the conventional type knock sensor, and a more precise ignition timing control is possible.

---: Conventional Type

Voltage

Voltage

A:Detection Band of Conventional Type B: Detection Band of Flat Type

Frequency (Hz)

A:Detection Band of Conventional Type B: Detection Band of Flat Type

Frequency (Hz)

Characteristic of Knock Sensor 214ceo4

2) Construction

The flat type knock sensor is installed on the engine through the stud bolt installed on the cylinder block. For this reason, a hole for the stud bolt is running through in the center of the sensor.

Inside of the sensor, a steel weight is located on the upper portion and a piezoelectric element is located under the weight through the insulator.

The open/short circuit detection resistor is integrated.

Steel Weight

Insulator

Piezoelectric Element

Open Circuit Detection Resistor

Open Circuit Detection Resistor

Insulator

Piezoelectric Element

Main Engine Control SystemEngine Control System Components

Piezoelectric Element

Vibration Plate

Piezoelectric Element

Vibration Plate

Flat Type Knock Sensor (Non-Resonant Type)

Z14CE01

Conventional Type Knock Sensor (Resonant Type)

Z14CE0Z

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