Star diagnostic helped fix W211 2008 E280 regular smoking

This post begins with the problem that regular smoking happen to w211 2008 e280 V6 estate Diesel, then with the senior technician help find out the problem, finally with the help of SD Connect C4 which can reset the air filter, finally problem solved.


Car model and year:

w211 2008 e280 V6 estate Diesel


Problem description:

Car is smoking plumes of smoke when I accelerate over 2000 rpm. I only happen during this phase. Other than that the car drives (seemingly) well with no issues, no stuttering, no start up issues. It’s black smoke.

Economy is average 32mpg and long drives at 40 mpg, which is lower than other users get for the same engine (appreciate the driver is a big variable in peoples economy figures)

As a starter when I bought the car last month I changed the oil, fuel, air and pollen filters. New oil (fully synthetic 5/40), and also used so Wynns clean burn treatment. But the problem has’t gone away. The exhausts are constantly covered in soot. I thought it may just be that it needed some TLC and a good run to clear out the engine, but there’s been no change in its behavior.


Working suggestion: get the codes read

First of all I would get the codes read on the car to see if anything is wrong, You say you have fitted new air filters to the car did you have the ecu regen after this. The black smoke after 2000 rpm could possibly be caused by a bad o2 sensor and the motor overfueling as a result of an incorrect signal from that.

32 mpg average is what I get from my 2008 280 as well so I don’t think it’s far out, I am guessing that you do short journeys in the car as that what hurts my mpg.

code reader advised: SD Connect C4

  • STAR diagnostic machine

The ECU needs to be told that a service has been done and more importantly, that the air filters have been changed. This is done only through STAR diagnostic machine better

SDconnect C4.

O2 sensor issues are quite common in the W211 facelift.

Get the car checked by a SDconnect C4 machine.

The air filter ‘reset’ is a separate function in STAR machine to resetting the ASSYST (spelt correct?) after service.

  • How SDconnect C4 reset air filter?

The operation picture on how SD Connect C4 reset air filter is not available now, but I am sure I confirm it is working. I take my sd connect c4 for example, I bought from Just browse.


Finally, solved!

Mechanic at local garage found that the central pipe connecting the two air intakes had a small crack in it, despite the tightly fitted jubilee clip over it. I don’t know the technical name for the part, but it was replaced. It also explained where the slight whirring noise from the engine was coming from on acceleration as air was escaping out of it.

The part has since been replaced, had fuel treatment again and a good motorway run.

Now there’s virtually zero smoking and soot from the exhaust. I also noticed a improvement in power and economy has improved slightly. Now getting 35 – 44 mpg. SO glad.

Now I can finally chrome polish the exhausts.