Toyota Corolla

1992-1998 of release

Repair and operation of the car

Toyota Corolla
+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engines
+ 4. Cooling systems, heating
+ 5. Fuel, exhaust systems
- 6. System of decrease in toxicity
   6.1. Specifications
   6.2. Electronic control system
   6.3. Electronic control unit
   + 6.4. System of onboard diagnostics
   + 6.5. Sensors of system of automatic control of the engine
   6.6. System of catching of vapors of gasoline
   6.7. System of recirculation (EGR system)
   6.8. System of compulsory ventilation of a case (PCV system)
   6.9. Catalytic converter
+ 7. Transmissions
+ 8. Coupling and half shafts
+ 9. Brake system
+ 10. Suspension bracket and steering
+ 11. Body
+ 12. Electric equipment


6.2. Electronic control system


Place of installation of devices of control systems of the engine and decrease in toxicity

1. Ignition key
2. Relay of the fuel pump
3. Control unit of the engine
4. Socket 1 of a data transmission channel
5. Control air valve of idling
6. Auxiliary sensor of concentration of oxygen (1 *)
7. The air temperature sensor on the soaking-up collector
8. Car speed sensor
9. Position Park/Neutral switch (2 *)
10. Sensor of concentration of oxygen
11. Main sensor of concentration of oxygen (2 *)
12. Sensor of temperature of cooling liquid
13. Integrated block of electronic ignition of Toyota (IIA block)
14. Nozzle
15. Sensor of an angle of rotation of a butterfly valve (TPS sensor)
16. The sensor of absolute pressure on the soaking-up collector (MAP sensor)
17. Amplifier of air conditioning system
18. The electropneumatic valve of compensation of turns of idling at turning on of the conditioner
19. Guard of devices
20. Fuel pump

1 * only for cars of the State of California (USA)
2 * only for cars with automatic transmission

Control of system of injection of fuel is exercised of the onboard microcomputer called by an electronic control unit (ECM).

Information from various sensors tracing such working parameters of the engine as the volume and temperature of the sucked-in air, temperature of cooling liquid, engine turns, the mode of dispersal or braking by the engine, concentration of oxygen in exhaust gases, etc. comes to an electronic control unit. Signals are used by an electronic control unit for the correct determination of duration of injection of fuel. On the basis of the data obtained from sensors, the control unit determines the optimum duration of injection of fuel.

The system is similar to the central nervous system of the person. Sensors (the nervous terminations) constantly transmit signals to an electronic control unit (to system "brain") which processes the obtained data, and, in case of need, sends team for change of working parameters of the engine (to a body).

Let's give an example of functioning of a part of this system.

The sensor of concentration of oxygen screwed in a final collector constantly traces the content of oxygen in exhaust gases. If percentage of oxygen in exhaust gases is higher than norm, then the electric signal is sent to an electronic control unit. The electronic control unit obtains this information, processes it and then gives the command in the control system of fuel injection forcing to change composition of gas mixture. On the working engine it occurs in fractions of a second and proceeds continuously. The end result is maintenance of composition of gas mixture at the set level, irrespective of driving conditions.

In case of refusal the sensor the reserve scheme imitating the faulty sensor which provides preservation of road performance of the car before malfunction elimination joins.


The considered cars are equipped with safety cushions. At any time at the connected battery, the pillow (which has a rigid design) can be developed (to be inflated). To exclude casual operation of a pillow (and possible injuries) when performing any works near safety cushion details, turn the ignition key in situation Lock and disconnect the battery from weight. After shutdown of the battery wait two minutes (necessary for a full discharge of the reserve condenser). More detailed description is provided in subsection 12.24.

Before a battery detachment from weight be convinced that the code of a raskodirovka of the radio tape recorder is known to you (if the last is equipped with the blocking device in case of plunder).

Follow the following rules:
       – before a detachment of any electric sockets always power off onboard system of the car turn of the ignition key in position of OFF, or having disconnected the battery from weight;
       – at installation of the rechargeable battery observe polarity of connection of cables;
       – it is forbidden to subject to strong blows of a detail of system of electronic injection of fuel and system of decrease in toxicity during removal or installation;
       – be accurate during search of malfunctions. Even short-term short circuit of conclusions of sockets can result in the wrong results of check or to failure of one of numerous transistor schemes;
       – it is forbidden to repair independently the control unit, or to open a cover of the case of an electronic control unit;
       – do not allow hit of water on system sensors at their survey during rainy weather. At a sink of a compartment of the engine do not spray water on sensors and sockets of a control system.