Upstream oxygen sensors can have two types of malfunction:
- mechanical failure in the electrical part (breakage, broken wire), which leads to a malfunction in the electrical circuit;
- deterioration of chemical characteristics, which leads to an increase in the response time of the sensor, and, consequently, to an increase in the period of its response.
After the test conditions are met, the obtained sensor periods are averaged (discarding parasitic effects) and compared with the average threshold period included in the on-board diagnostics system.
Test conditions
Upstream oxygen sensor diagnosis can only be performed if the pre-ignition conditions are met and met.
- no electrical faults;
- programming done;
- no mixture misfires detected;
- coolant temperature above 40°C;
- the average engine speed is in the range of 650-6200 min-1;
- engine load does not matter;
- movement speed doesn't matter.
Troubleshooting
Diagnosis is performed by the customer during the trip in accordance with the conditions described above, when the absorber purge is disabled. The ECU issues an instruction «oxygen sensor diagnostics: done».
Attention! At the end of this test, never switch off the ignition before reading the result on the scan tool. Switching off the ignition leads to incorrect interpretation of the results.
Repair Confirmation
«Diagnosis using the oxygen sensor on-board diagnostic system: «COMPLETED ACTIVELY».
Oxygen Sensor Malfunction: «NOT ACTIVE».
Oxygen sensor repair confirmation: «YES».
If the scan tool displays Oxygen Sensor OBD Diagnostic: Passed. ACTIVELY» or «Oxygen sensor repair confirmation. 1 DEF», then the control cycle was executed incorrectly. In this case, repeat the control cycle under strict observance of the diagnostic conditions.
If a message appears on the screen of the diagnostic tool after the test «Malfunction of the catalytic converter. ACTIF» or «Oxygen sensor repair confirmation. 2DEF-, refer to the diagnostic method of the corresponding fault.