غلبة الرحلات القصيرة

A usage pattern rather than a fault: journeys too short for the engine and its aftertreatment to reach operating temperature. The vehicle is working correctly and is being asked to do something it was not designed for, which is worth stating because the diagnosis otherwise chases parts that are all in order.

Almost everything downstream of the engine needs heat. A particulate filter cannot regenerate below its light-off temperature, a catalyst does not convert until warm, condensation in the exhaust and crankcase never evaporates, and the battery never recovers what starting took. So the codes cluster — filter loading, catalyst efficiency, emissions monitors that never complete, a battery that keeps failing — and each looks like a separate fault.

The evidence is in the data, not the parts. Look at the count of incomplete regenerations, the ratio of engine starts to distance travelled, and whether coolant temperature reaches its target in a typical trip. The remedy is a longer run at sustained load, and if that is not compatible with how the vehicle is used, that is a genuine finding for the owner rather than a repair. Say so plainly — it is more useful than a part that will not change anything.