[Schomosport]

Repeatedly getting fault code 30DE NOX correlation error - have tried to interpret per Bimmerprofs as below. I suspect it has gone intermittent and needs replacing, other interpretations welcome.

I need to add the two wideband lambda sensors to the test script and repeat the test run so that I can compare them but have't found time to do it yet.

NOx-Konzentration (2) goes intermittent dropping to zero even above 20kph. BimmerProfs says it's failed due to ageing. However, error 30EA has never been recorded during ownership.
Schubabschaltung (3?) (over-run mode) is 1 or 2, much less than the 5 - 15 figure given by BimmerProfs.
Inconclusive if Lineares Lambdasignal (4) in over-run mode is always correct. It is 25 in the clear over-run period which is understood to be acceptable, however plot is too messy to see if all the other excursions to 25 (limit?) co-incide with throttle over-run. The wide-band Lambda probe values were not obtained in this test so cannot compare, need to repeat test. However, looking at values in fault log 240101_fsdatei.txt shows the NOx Lambda is very different to the wide-band Lambda while the trace for Lineares Lambdasignal (4?) is typically 5 or greater.

fault log 240101_fsdatei.tx
lineares Spannungssignal NOx-Sensor 3.98 - 3.98 -
Lambda-Istwert Gruppe 1 1.00 - 1.36 -
Lambda-Istwert Gruppe 2 1.00 - 1.41 -

Engine is 2007 N53 330i 92k miles

Setting aside the irritation of the car not running as BMW intended, and the expected cost of NOX sensor replacement, I find investigating this stuff really interesting but maybe I am just plain sad!