AD07.61-P-4000-15B | ME-SFI fault code description secondary air injection malfunction (function chain) | With CODE (620a) vehicles with three way catalytic convertor (TWC) technology |
1 | Fault code | right cylinder bank left cylinder bank |
2 | Fault memory and actuation of CHECK ENGINE (MIL) | After two consecutive journeys with fault |
3 | Frequency of testing | Once per journey |
4 | Checked signal or status | Oxygen sensor signals before TWC |
5 | Limit value Duration of test | Lambda control factor approx. + 25% (lean mixture recognized, engine control module (ME-SFI) at "rich" stop) < 15 s |
6 | Test conditions | – Engine idling – Vehicle stationary – Air pump actuated at least once after engine has started – No faults with voltage supply to purge control valve, air pump switchover valve and electric air pump/air pump electromagnetic clutch – No purge control fault – No actuator fault – No combustion misfires – No fault in oxygen sensor before TWC, ageing – No CAN data bus fault – Self-adaptation of mixture formation not at limit value – Air pressure above approx. 780 hPa (i.e. no test carried out above an altitude of approx. 2500 m) – Engine coolant temperature < 90°C – Lambda control enabled |
7 | Test sequence | When the functional chain starts, all functions for automatic mixture adaptation are disabled, the purge control valves are closed and the current Lambda control factor is recorded. This is followed by secondary air injection. The mixture must weaken. The Lambda control factor responds appropriately with an increase of approx. + 25%. |
8 | | If a condition changes while testing, the test is terminated and started again later. |