AD07.61-P-4000-16C | ME-SFI fault code description catalytic converter efficiency insufficient | With CODE (620a) vehicles with three way catalytic convertor (TWC) technology |
1 | Fault code | right left |
2 | Fault memory and actuation of CHECK ENGINE (MIL) | After two consecutive journeys with fault |
3 | Frequency of testing | Continuous |
4 | Checked signal or status | Voltage ratio (amplitudes) of oxygen sensor signal after TWC to oxygen sensor signal before TWC |
5 | Limit value Duration of test | Oxygen sensor signal after TWC is a maximum of 50% of oxygen sensor signal before TWC (on more than 2 out of 9 measurements) approx. 210 seconds |
6 | Test conditions | – Engine speed approx. 900-2000 rpm – Load approx. 10% to 45% – Three way catalytic converter temperature > 350°C – Lambda control enabled and Lambda > 0.4 – No oxygen sensor fault (signal, heater, ageing) – No combustion misfires |
7 | | The three way catalytic converter is evaluated for its ability to store oxygen. Several measurements must be made in the specified engine speed and load range. The results are compared with a performance map and so any fault is recognized. The amplitude of the oxygen sensor voltage after TWC must only be a maximum of half the amplitude of the oxygen sensor voltage before TWC. (Note: If, for example, no monolith was installed in the three way catalytic converter the oxygen sensor signals would be identical before and after TWC). If the fault codes were issued for the three way catalytic converter and for the oxygen sensor before TWC at the same time, first replace the oxygen sensor before TWC. If no TWC fault is subsequently recognized, the effectiveness of the three way catalytic converter is slightly reduced, but it does not need to be replaced yet. |