C180K High Idle (W203)

[gregives]

Hi all,

I've been having a bit of trouble with my C180K recently, the engine warning light came on at the end of last week during normal driving and after checking the fault code today and on an OBD reader (believe it was p0172 but need to double check) I'm trying to work out what's happening with the car.

At the moment the fuel economy appears to be fairly normal, seeing 38mpg on a mixed run of A/B roads to work.

The idle does rise to about 1400rpm once the engine is warmed up and the car is in P.

Has anyone seen this before?

Thanks in advance!

Greg

Edited by gregives on Tuesday 13th May 22:15

[mbtech01]

If your C180k is fitted with the 271 engine then I suspect you have a split breather hose that is located under the air filter housing that connects between the inlet manifold & lower crankcase assembly. The pipe comes in several pieces but generally its the upper section that splits leading to incorrect air mass readings etc due to an air leak which the gives you various fault codes like self adaption faults, air mass faults etc etc.
Its a fairly common pipe that fails & I've lost count at how many I've replaced. Its a bit fiddly to do as a diy job but with the right tools & some patience it doesn't take too long to do.

[gregives]

mbtech01 said:

If your C180k is fitted with the 271 engine then I suspect you have a split breather hose that is located under the air filter housing that connects between the inlet manifold & lower crankcase assembly. The pipe comes in several pieces but generally its the upper section that splits leading to incorrect air mass readings etc due to an air leak which the gives you various fault codes like self adaption faults, air mass faults etc etc.
Its a fairly common pipe that fails & I've lost count at how many I've replaced. Its a bit fiddly to do as a diy job but with the right tools & some patience it doesn't take too long to do.

I believe it is fitted with the M271 engine, that would certainly be a huge relief if that was what was causing the problem. A lot of the reading I'd done online had seen people spending silly amounts of money on MAFs and other bits to chase the problem.

Would it be possibly to tell by visually inspecting it? Is the pipe fairly easy to get hold of or is it worth taking the car to an indy?

Thank you so much for the reply!

[mbtech01]

you cant visually see the pipe unless you remove the complete airbox assembly. You may hear a hissing noise coming from this area when the car is idling which would indicate a split hose but most of the time you just have to remove the airbox & have a look.
If you do remove airbox then have a good look at rest of breather pipe that sits down under inlet manifold & tucked behind supercharger as recently I've had 2 cars that have both had broken breather pipes/check valves which has resulted in removal of inlet manifold/supercharger to replace these pipes/valve etc.
If this section of piping is broke then I would personally leave it to s specialist unless you really confident at doing things like this as it starts to get more involved in removing the inlet manifold/supercharger etc & you'll need a ramp to access various fixings underneath etc.

[gregives]

Sorry for dragging up and old thread but I thought it might useful for reference for anyone else in the future who suffers this problem.

I did eventually find a resolution to the problem, as suspected here in the thread the issue was with the breather hose (A 271 018 12 82). The car was suffering the symptoms I mentioned in the earlier posts as well as throwing up error codes and setting the CEL on. There was a distinct hissing noise coming from the intake side of the engine.

However after replacing the hose, the car is running perfectly again and the noise is gone. Having reset the CEL and taken it for a test drive, this seems to have cleared the fault.

I replaced the hose myself in the end and can offer some advice to anyone looking to do this themselves:

1) Make sure you have a 1/4" E10 socket for undoing the bolts on the airbox

2) Consider changing the clamp at the furthest end of the hose but be careful as there is limited space to refit it, so tightening jubilee clips etc. is tricky.

There is a fantastic DIY guide here on this forum (hopefully it stays up for the forseeable future) http://mbworld.org/forums/c-class-w203/233246-diy-...

For reference too, here is a picture of my engine with the split hose..

[Mickolena]

Couple of years late but I seem to have a similar problem although I don’t have any warning lights on the dash but also haven’t checked for error codes yet. My car is idling pretty rough and also there is rattling and vibrating under the air intake box. Any ideas why the rattling and vibration? Thanks in advance.