Conditions for storing fault codes
The effectiveness of the catalytic converter is determined by comparing the signals from the front and rear oxygen sensors. The ECU stores a DTC and illuminates the Engine Management System Malfunction Indicator Lamp if the front and rear sensor signals are the same in two driving cycles for 60% of two or four 170-second test periods. The check is performed under the following conditions:
- The ECU operates in a closed control loop;
- crankshaft speed within 1800–2300 min-1;
- the temperature of the catalytic converter is above 372°C;
- the degree of cyclic opening of the adsorber purge solenoid valve is greater than 0.9;
- there is no gear shifting;
- engine load is in the range of 1.4–4.5 ms.
The output of this code indicates that the signals from the front and rear oxygen sensors have determined the low efficiency of the catalytic converter of the exhaust gases.