An indicator of the condition of a catalytic converter is its oxygen capacity. With the aging of the catalytic converter. its oxygen capacity is reduced in the same way as its ability to neutralize exhaust gases.
Conditions for starting diagnostics
Catalytic converter diagnostics can only be performed after the engine has been running for 17 minutes if the pre-ignition conditions are met and maintained.
- no electrical faults;
- cylinder recognition performed;
- no mixture misfires detected;
- after switching on the ignition, no diagnostics of the catalytic converter was carried out;
- programming done;
- the main and dual circuits for regulating the composition of the mixture are activated based on signals from oxygen sensors;
- coolant temperature above 75°C;
- The car is moving at a speed of 63 to 130 km/h;
- pressure is in the range of 430-650 mbar;
- engine speed read from the scan tool. is within 1824-3712 min' for the F4P engine and 1824-4000 min' for the K4M engine.
Troubleshooting
Diagnostics is performed when the car is moving in 5th gear at a speed of 70 km/h. If the conditions for starting the diagnostics are met, the process of enriching the mixture is delayed in time, which leads to the flow of portions of oxygen into the catalytic converter. If the catalytic converter is operational, it absorbs oxygen and the voltage value of the signal of the lower oxygen sensor remains at an average level. If the catalytic converter has exhausted its resource, then oxygen is not absorbed and the oxygen sensor starts to work intermittently. The oxygen sensor signal voltage will fluctuate. On-Board Diagnostic Warning Light» will light up after three trips. The duration of the test cannot exceed 52 s without exiting the loop.
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
Issue a command «diagnosing the catalytic converter using the on-board diagnostics system»: «ACTIVELY».
«Catalytic Converter Diagnosis with On-Board Diagnostics: Completed»: «ACTIVELY».
«Malfunction in the operation of the catalytic converter»: «NOT ACTIVE».
«Catalytic Converter Repair Confirmation»: «YES».
If the scan tool shows «On-Board Diagnosis: Completed. ACTIVELY» or «Catalytic Converter Repair Confirmation. 1DEF», 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 8 operation of the catalytic converter. ACTIVELY» or «2DEF Catalytic Converter Repair Confirmation», refer to the diagnostic method of the corresponding fault.