Repair and Toyota Corolla car operation - 6.5.2. Sensor of concentration of oxygen//Toyota Corolla of 1992-1998 /

Toyota Corolla

1992-1998 of release

Repair and car operation



Toyota Corolla
+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engines
+ 4. Systems of cooling, 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
      6.5.1. The sensor of temperature of cooling liquid
      6.5.2. Sensor of concentration of oxygen
      6.5.3. Sensor of an angle of rotation of a butterfly valve (TPS sensor)
      6.5.4. The sensor of absolute pressure on a soaking-up collector (MAR-datchik)
      6.5.5. The air temperature sensor on a soaking-up collector (IAT sensor)
      6.5.6. Temperature sensor of system retsirkulyatsiya (EGR sensor)
      6.5.7. Sensor of speed of the car (VSS sensor)
      6.5.8. Detonation sensor
      6.5.9. Sensor of an angle of rotation of the crankshaft
   6.6. Catching system паров gasoline
   6.7. System retsirkulyatsiya (EGR system)
   6.8. System of compulsory ventilation of a case (PCV system)
   6.9. Catalytic converter
+ 7. Transmissions
+ 8. Coupling and semi-axes
+ 9. Brake system
+ 10. Suspension bracket and steering
+ 11. Body
+ 12. Electric equipment



6.5.2. Sensor of concentration of oxygen

GENERAL INFORMATION

Sensor of concentration of oxygen

1. The socket of the warmed-up sensor of oxygen from the sensor

2. The socket of the warmed-up sensor of oxygen from conducting

3. The warmed-up sensor of oxygen
Cars are equipped or one sensor of concentration of oxygen, or two sensors. In system with two sensors of oxygen the main sensor of concentration of oxygen is established in front of the catalytic converter and traces the content of oxygen in the exhaust gases leaving the engine. The auxiliary sensor of concentration of oxygen traces the content of oxygen in exhaust gases after the catalytic converter. The sensor of concentration of oxygen reacts to the content of oxygen in exhaust gases and generates target tension fluctuating from 0,1 In (the high content of the oxygen, the grown poor mix) to 0,9 In (the small content of the oxygen, the enriched mix).

Changing target tension from sensors moves on the electronic control unit which defines an oxygen and fuel ratio in gas mixture. The control unit regulates an air / fuel ratio in a mix by a task of time of an open condition of nozzles. At a ratio of 14,7 parts of air to 1 part of fuel in an initial mix the content of harmful substances in exhaust gases minimum, at such ratio the catalytic converter clears gases with maximum efficiency.

The electronic control unit together with the sensor of oxygen provide maintenance of composition of gas mixture just at the specified level.

If the temperature of the sensor of concentration of oxygen is lower than normal working temperature, i.e. below 300 ° With, tension on the sensor will be absent. Therefore, until then while the engine will not get warm, on the electronic control unit of a signal from the sensor of oxygen does not arrive and the block works in a mode of the opened cycle.

If after engine warming up, or not less than 2 minutes of operation of the engine later, and on the main sensor of concentration of oxygen tension not exceeding 0,7 In steadily develops at speed of rotation of the engine of 1500 rpm, the electronic control unit will establish a code 21. The code 27 will indicate malfunction of the auxiliary sensor of oxygen.

If the sensor or its chain are faulty, the electronic control unit works in a mode of the opened cycle, i.e. the block doses out fuel according to the programmed value on its entrance, instead of according to a signal of the sensor of oxygen.

The correct operation of the sensor depends on four conditions:

      – the electric: the low voltage generated by the sensor, very strongly conditions of connections with wires which always should be pure and strong and is checked first of all, both in case of signals of system of self-diagnostics, and at suspicion on malfunction of the sensor;
      – supply of external air: the sensor is arranged so that air circulates in its internal space. Every time at removal or installation be convinced of purity of air channels of the sensor;
      – working temperature: signals from the sensor do not arrive on the electronic control unit until the temperature of the sensor will not reach about 300 ° With (this factor should be considered at an assessment of serviceability of the sensor);
      – use of unleaded gasoline is an essential condition of the correct operation of the sensor.

Besides specified above conditions that at service of the sensor it is necessary to observe the following special rules:

      – the flexible conductor and the socket of the sensor of oxygen are not folding and from the sensor are not disconnected;
      – damage or a separation of the flexible conductor or the socket can adversely affect serviceability of the sensor;
      – it is not allowed hits of dirt, lubricants and other extraneous components on the socket or on a tower insulator of the sensor;
      – it is forbidden to wipe the sensor all types of cleaners;
      – it is forbidden to drop the sensor or carelessly to address with it;
      – watch correctness of installation of a silicone cover of the sensor to avoid cover melting because of which failure of the sensor is possible.

Check
PERFORMANCE ORDER
1. For check of the sensor connect the digital voltmeter and on the working engine track indications (the voltmeter should show tension at level in volt shares). For this purpose find the socket of the sensor of oxygen and enter щуп the voltmeter into contact to a wire of black color from a reverse side of the socket of the sensor.
2. Correctly to incorporate to a wire of the socket dress on a wire long a straight line shtyrevy a sampler and enter a sampler on a wire into the socket against the stop in metal contact of a wire. Connect positive щуп the voltmeter to a sampler, and negative щуп with weight.
3. Start the engine and throughout warming up watch tension from the main sensor of oxygen (tension should be up to standard of volt shares). The sensor of concentration of oxygen will constantly generate a signal of tension which on the cold engine (the opened cycle) makes 0,1–0,2 volts. About 2 minutes later the engine will get warm to working temperature and tension from the sensor of oxygen will fluctuate in limits from 0,1 to 0,9 volts (the closed cycle of engine management joins). If the signal from the sensor of oxygen differs from the specified values, the sensor is subject to replacement.
4. For access to the socket of the auxiliary sensor of oxygen it is necessary to remove a forward seat of the passenger.
5. For check of the auxiliary sensor of oxygen find the socket and execute the same checking procedures as with the main sensor of oxygen.
6. Check a heater of the auxiliary sensor of oxygen (if is available) as follows. Disconnect the socket of the sensor of oxygen and attach an ohmmeter between contacts +В and NT in the socket from the sensor. The indication of an ohmmeter should be within 11,0–17,0 Ohm.

Prevention

With the warmed-up sensor of concentration of oxygen are completed only a part of cars. The socket of the warmed-up sensor of oxygen has four contacts.


7. Check supply voltage of a heater of the sensor of oxygen. At the included ignition (the engine does not work) check tension existence from the battery between black-red (positive +) and black-blue (the negative–) wires in the socket from conducting.
8. On models of 1993-1994 the sensor of oxygen can be checked in a different way. On completely heated-up engine and at the connected sensor of oxygen connect positive щуп the voltmeter to a conclusion of VF1 of the diagnostic socket (it is specified by an arrow), and negative щуп – to conclusion Е1. Finish speeds of rotation of the engine to 2500 rpm, connect contacts THAT 1 and Е 1 diagnostic socket a wire or a writing paper clip.

Prevention

Measure tension by only the strelochny voltmeter as it is necessary to watch arrow fluctuations.


9. Sustain the engine at speed of rotation of 2500 rpm for about 2 minutes connect contacts THAT 1и Е1 the diagnostic socket. Check number of deviations of an arrow in 10 seconds. The quantity of deviations of an arrow should be not less than 8. If the quantity of deviations of an arrow is less, warm up the engine once again and repeat check.
10. If quantity of deviations of an arrow on former less than 8, remove a crossing point connecting conclusions THAT 1и Е1. Supporting speed of rotation of the engine of 2500 rpm, measure tension between conclusions of VF1 and Е1. If tension a more than 0 In, replace the sensor of concentration of oxygen. If tension is equal 0, consider self-diagnostics codes (see subsection 6.4.1) and establish a cause of failure.
11. If codes 21, 25 or 26 are received, disconnect a vacuum hose of system of compulsory ventilation of a case from a cover of a head of cylinders (see subsection 6.8) and measure tension between VF1 and Е1. If tension is equal 0, replace the sensor. If measured tension exceeds 0 In, the engine works with the reenriched mix and power supply system repair is required.
12. If other codes are received, repair the concrete sensor or a chain.

Replacement


Prevention

When cooling the final collector or an exhaust pipe in which will screw the sensor, are compressed, therefore, on the cold engine to unscrew the sensor difficultly. Not to damage the sensor (it is supposed that you will use it further) start and warm up the engine within 1–2 minutes, stop the engine. Be careful not to get burns at performance described below actions.


PERFORMANCE ORDER
1. Disconnect the storage battery from weight.
2. Lift the car and establish on supports.
3. Accurately disconnect the socket from sensor conducting.
4. Turn out the sensor of concentration of oxygen from an exhaust pipe (on a photo the special extended face head facilitating an otvorachivaniye of the sensor) is represented.


Prevention

Not to strip a thread the sensor do not make too big effort at an otvorachivaniye.

The sensor of oxygen can be screwed in a final collector or fasten two bolts.


5. For simplification of the next removal of the sensor it is necessary to use structure against прихвата carvings. The structure is always put on a carving of new sensors, but at removal and the subsequent installation of the sensor which was in operation it is necessary to put structure again.
6. Reliably tighten the sensor.
7. Attach the socket of conducting of the sensor to the main plait of conducting of the engine.
8. Lower the car and attach the storage battery to weight.