Engine light ON

[falcoFBS]

Hello everybody.

First of all I apologize for my English skill, will try the best as I can.

My 1st post here -unfortunately for bad reason and will much appreciate if someone can give me some advise.

So, my car is C200K Petrol, Manual, 2001, 70000 miles.

Here is the problem.
Two months ago the engine light on the display come ON. The dealer set Air Mass Sensor is faulty.
New part from Mercedes is about £300, so I bought from e-bay brand new coming from Chine for £40.
Replaced it (everything was ok) and after 10 days the light again ON.
The dealer check again and found that the magnet (in front of engine) and plug was in oil. So new magnet and good cleaning sort the problem for 2 days (about 100 miles), and again the light.
After that I left the car for 3 days to dealer to check, try and replace what ever they think.
So they replaced two sensors (presure sensors) which I don't know. They just set there are exactly the same parts number but in different place (one is close to the Air Mass sensor).
They test the car for 200 miles (3 days) without any problems.
Yesterday I collected the car and unfortunately today (after 30 miles) -again the light.

Tomorrow again I will visit the dealer, but I'm worry how far this problem can go.
Is the way to solve this problem is to replace everything possible?
I think should be way when I go to dealer specialists and they have all modern equipment to find out what is exactly the problem and not to cost so much for unnecessary replacing some parts - for me it looks like guessing!

Once again I will much appreciate for any advises. Thank you!

 

[television]

Hello and welcome.
First you must check to see if any oil is coming from the camshaft sensor and getting into the wiring loom and then coming out onto the MAF.

So is the MAF oily inside, is there any oil on the MAF plug.

Ebay China made MAFs do not last long in our experience of them.

The MAF will not turn on the engine lamp, but oil coming through from the loom will, as it gets onto the O2 sensor, and it is this sensor that turns the lamp on

 

[dragon]

It still safe to diagnose before the next step is taken. Surprised you took it to the dealer with all the tools, they didn't tell you what the problem is.

 

[falcoFBS]

It still safe to diagnose before the next step is taken. Surprised you took it to the dealer with all the tools, they didn't tell you what the problem is.

My mistake - sorry.
I mean they have all the tool and equipment.
And thank you for the quick response.

Also when I visit the dealer for 1st time they set the computer show Air Mass Sensor. I will check again the plug, but I think that plug was without oil.

 

[dragon]

If they already told you the problem is the MAF and nothing else then the fraud MAF won't work. Why don't you pop into a Bosch dealer to get one as Malcolm said it only £145 and even more from a Merc dealer.

Get this one fixed first and look at the other problems from there. If the problem is still there then get diagnostic tool to clear all the fault codes and do a quick test.

 

[falcoFBS]

I've been already twice to the dealer in the last two weeks.
They've replaced (not sure for the name) the parts on the top of the sparking plugs and topped up the petrol with some cleaner.
Unfortunately again LIGHT.

I checked all the plugs in MAS sensor, CAM (magnet) sensor and O2 sensor - everything looks OK without any oil.
Just don't know what to do now.

 

[television]

So they have replaced the plug caps,, these will not put the Lamp on, and neither will the MAF on its own rights. The O2 sensor can and will turn on the lamp if it has moved too far away from its stored setting.

If the wiring loom was not replaced, then oil can seep out and and into the MAF, it gets burnt in the engine, this fouls the O2 sensor and on comes the light

 

[falcoFBS]

GOOD NEWS (fingers cross)

Now about two months latter and 1500 miles - everything looks to be OK.
So, what was the problem - dirty throttle body.
After good cleaning and even I put back the old original Air Mass - the Light has gone.
Just hope no problems for many years.
Thanks to everyone and wish to all of you safe journey.