The fault code does not get stored until the fault happens three times. The fault code can be seen if the engine is left running. Its often shows as low manifold pressure.
This thread is a bit old and not very helpful. A general approach to front brake imbalance is to ensure the pistons are free and the pads are not jamming in the calipers. Push the pistons back and operate the brakes. Do this a few times and check that pistons always seat properly. Next remove...
I have had a similar fault caused by oil surge in the crankcase. 2007 E320S CDi. The fault also occurs when accelerating hard up a steep hill. However, it only occurs when the oil level falls below halfway on the dipstick. (my oil level drops due to leaking oil cooler seals).
Its unlikely your...
Getting back to the fumes, its worth tuning your nose to the smell of different fumes. Burning, oil, hot oil, exhaust, fuel, windscreen washer fluid, hot coolant leaks, these are the smells you will come across.
For the record: Fitting the the resistor provides a perfect result with no effect on emmisions, performce, or consumption. The swirl flaps seem to a not needed complication, ie expense.
I had a similar fault on a 2007 E320 5 years back. Same solution, remove the connector and plug back in again. The fault reappeared after 6 months, same solution. 3 months, same. 1 month, same. Eventually every day. I went to a cluster repair man and he told me the fault was not repairable...