Mazda 626

1991-1998 of release

Repair and operation of the car

Mazda 626

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engines
+ 4. Heating and ventilation
+ 5. Fuel system
- 6. Exhaust system
   + 6.1. Exhaust system
   - 6.2. Systems of decrease in toxicity of exhausts and management of operation of the engine
      6.2.1. Introduction
      6.2.2. System of self-diagnostics and codes of malfunction
      6.2.3. Central control unit
      6.2.4. Sensor of provision of a butterfly valve
      6.2.5. Air stream sensor
      6.2.6. The sensor of temperature of the arriving air
      6.2.7. Sensor of temperature of cooling liquid
      6.2.8. Sensor of provision of a bent shaft
      6.2.9. Sensor of position of the camshaft
      6.2.10. Switch of system of hydrostrengthening of steering
      6.2.11. Oxygen sensor
      6.2.12. Sensor of detonation combustion of fuel
      6.2.13. Speed sensor
      6.2.14. Air valve
      6.2.15. System of additional air supply on low turns
      6.2.16. System of ventilation of a case
      6.2.17. System of recirculation of exhaust gases
      6.2.18. System of collecting vapors of fuel
      6.2.19. Switch of fires of a stoplight
      6.2.20. Catalytic converter
+ 7. Transmissions
+ 8. Coupling and half shafts
+ 9. Brake system
+ 10. Running gear
+ 11. Body
+ 12. Electric equipment
+ 13. Electrical circuitries
+ 14. Useful tips


6.2.11. Oxygen sensor


The oxygen sensor checks the content of oxygen in exhaust gases. On the basis of information from the oxygen sensor the electronic control unit regulates composition of fuel mix.


1. For check of primary sensor (located in front of the catalytic converter) connect the positive probe of the voltmeter to the alarm plug of the sensor, and minus the probe – to the weights plug.
2. Start the engine and check that tension between plugs made 0,1–0,2 Volts while the engine cold (the engine works in the open mode). Approximately in two minutes the engine and the oxygen sensor have to get warm and tension has to begin to fluctuate between 0,1–0,9 Volts (the electronic control unit passed into the closed operating mode).
3. Check that resistance of a heating element of the sensor made 10–40 Ohms. Check giving of tension for a heating element.
4. Replace the oxygen sensor if it is faulty.


1. Disconnect the socket of connection of the sensor and accurately unscrew the sensor.
2. Grease a carving of the new sensor before installation by anticorrosive structure. Installation is carried out upside-down removals.

On the homepage