An indicator of the condition of a catalytic converter is its oxygen capacity. As a catalytic converter ages, its oxygen capacity decreases as does its ability to neutralize exhaust gases.
Conditions for starting diagnostics
The catalytic converter diagnosis can only be performed if the pre-ignition conditions are met and fulfilled.
- no electrical faults;
- no mixture misfires detected;
- programming done;
- the main and dual circuits for regulating the composition of the mixture are activated based on signals from oxygen sensors;
- engine RPM read from scan tool is between 1120-1840 rpm-1.
Troubleshooting
Diagnostics is performed while maintaining the engine load within 20-30% and the crankshaft speed within 1120-1840 min-1. Subject to the conditions for the start of the diagnosis. the process of enrichment of 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 catalyst has exhausted its resource, then oxygen is not absorbed and the oxygen sensor starts to work continuously. The oxygen sensor signal voltage will fluctuate. The on-board diagnostics warning light will come on after three consecutive trips. The catalytic converter diagnostic lasts 60 seconds.
Attention! At the end of this toast, under no circumstances turn off the ignition before reading the result on the diagnostic tool. Switching off the ignition leads to incorrect interpretation of the results.
Repair Confirmation
«Catalytic Converter Diagnosis with On-Board Diagnostics: Completed»: «ACTIVELY».
«Malfunction in the operation of the catalytic converter»: «NOT ACTIVE».
If the scan tool shows «On-Board Diagnosis - Catalytic Converter: Failed. ACTIVELY», 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 in the operation of the catalytic converter. ACTIVELY» or «Catalytic Converter Repair Confirmation. 2DEF», refer to the diagnostic method of the corresponding fault.