digitallust_aus

Ok so I have to whinge... firstly has anyone noticed how NOTHING in the Australian Manual for the W205 actually matches the contents page?


Secondly, my engine light randomly came on this evening on my way home.. stopped and restarted the car and it still on. Car is running fine, about 5,000kms

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I live about 500km from my nearest MB dealership so its not as easy as just popping down there tomorrow.

Is there any other way to find out what may be causing the issue or is it down to diagnostics only?

Cheers, Matt

StanNH

This type of fault is often related to the emissions system. It could be nothing more than a faulty sensor, but there''s no way of knowing without reading the error code/codes that were generated.

Here, many dealers offer what is called "valet service." They will pick up your car and leave a loaner while the car is in for service. Have you asked your dealer if they'd be willing to do that? Alternately, you could try to find a local shop that can diagnose and service your car.

c4004matic

Stan H is correct.
However, before you get too concerned, make sure your gas cap is not loose. Gas up the car make sure the cap is tightened appropriately and keep on driving. After a drive or 2 the light should go out. If after a few drives the light persists then get service.

kellens

It's probably nothing, but as StanNH said, easy to know for sure.

Speedriven1

My thoughts exactly.

kellens

Ignore C4004matic...in general...but more than usual for your issue. You're well under warranty. If you don't have a reader, have dealer pull the code and know what it's was. EZ and free. Even if it's nothing, they're coming out with firmware regularly to fix a number of bugs with this car and one might address your code.

radarguy

Don't ignore him this time. I would tighten the gas cap before I drove 500 km for service. This is a very common problem regardless of the make.

49erPV

Not sure if the loose fuel cap triggering the engine check light applies to diesel or not?

c4004matic

Worth a try! The reason for the loose gas cap is that the whole system is pressurized. The check engine light will activate if anything with the emission system is faulty. The gas tank must maintain a certain pressure for the evaporative system to work correctly. Its probably the same with oil burners. In general if everything seems to be working fine the light does not mean anything too serious, if it were something significant you would know right away because of misfiring, loss of power or the engine simply going into limp mode.
With oil burners another common possibility simply bad fuel. Let us know how things go.

floridadriver

Ummm. Not really. Thanks to dealer who didn't tighten cap when handed car over as new, loose cap puts a chime and notification on the dash that makes that an easy diagnosis. And many codes and trips which would not cause misfiring or your other suggestions.

c4004matic

The check engine light is mandated by the federal government and varies from country. It monitors all systems associated with emissions so anything beyond recirculation system it checks the oxigen sensor and many other systems like fuel injection etc. However aside from the gas cap thing if there were something that would light it up such as a bad injector or misfiring spark, those would affect engine performance. Not everything, only things that's are emission related, as a matter of most of the other things that may throw up a code don't make it come on.
If you want more information, here's the ultimate source.

http://www.epa.gov/obd/

floridadriver

Ummmmm. No. And a bit off topic. The OP isn't in U.S. The check engine light covers more than emissions. The check engine light gets dash message fir some codes such as gas cap. And your suggestion of how his car would be running isn't accurate either.

Best advice on here IMO from StanNH and kellens...simple plug in reader will reveal your answer without wives tales.

c4004matic

Why don't you read the thing before you blab? Yes it covers different things in different countries as I already said, but in the USA, the function of the check engine light is directed by the OBDII mandated by the EPA. Emissions covers a lot of things as I already explained. Are you obtuse or willingly argumentative? Other countries have adopted the standard in its entirety or with their own modifications, but still does essentially the same thing.

floridadriver

I did read it. Still off topic and still you're still incorrect.

We should have a three times a thread spreading BS rule and you're out. You'd be looooong gone by now c4004matic.

c4004matic

How can the federal statute that governs not only the implementation of the device but what it does be off topic? THE CHECK ENGINE LIGHT IS THE ODBII signal light.
Iguess you are one of those people that don't believe in evolution either. Willingly stupid.

digitallust_aus

Thanks guys, I generally take my cars (the BMW and Mercedes type) to the dealerships in Perth which are 500km... Car on the truck me in the air.. usually once a year for servicing, however I have been lucky enough not to need any interim trips... however at the moment my list of items/issues to be sorted is growing, a trip is definitely imminent.

In saying that, last night, when I got home, I turn the ignition on but didn't start the car and noticed a gurgling liquid/fluid sound at the rear of the car (fuel tank?)maybe the tank was the issue. However the car still operated as normal.
That said, this morning I started it up and no light, maybe I was slightly over reacting when it came on, but it 20 years of driving I've never seen that light before :P

c4004matic

If the light does not recur you can be at ease. When the your time for check up come along they'll check the codes. Again if its something serious that needs attention it will come on again.
One of the biggest complaints about the check engine light is that it doesn't mean anything specific, it could be your gas cap or it could be a blown cylinder head! Some manufacturers like Honda will actually show some of the codes on your dash information system for example "check gas cap". I don't know if MB does.

parkwood

A 500km trip to a garage is pretty horrendous....most of us in europe winge if it is 50km (especially the poms only joking!). It makes it even more vital the car is solid and reliable.........you have my sympathy and i hope the fix suggested works.

Cmersu

I had the same issue with my C200. The NOX sensor had to be changed. This happened a few moths ago. My car had only 13500 km on it.

digitallust_aus

So the light went off, but today about a week later it came back on again.
Guess that trip to the dealer will be coming sooner rather than later.
So tell me, even if the light goes off again when I get it trucked to the dealer, will they still be able to read the previous error code?

c4004matic

Sorry to hear it. Yes the code will stay on memory. Anything else amiss that you can feel?
Also if you are mechanically inclined and live so far from a dealer. You may want to buy an OBD II reader. Its simply a dongle you put on your OBD port (right next to your hood handle under the dash). The codes are shown on your cell phone, some will even let you reset the codes if necessary. Make sure that the reader you purchase will read MB codes. They are less than 100 us dollars.

floridadriver

Sorry to hear of your continued issue. You really need to get to the dealer or a reader. Any other advice is like trying to read tea leaves.

Codes are saved, I've had some that didn't in other vehicles, but were there when I read them and didn't delete them. If it keeps coming on, the fix should be easier to find than an intermittent one at least.

digitallust_aus

So I called into a VW dealership that a friend locally owns and his mechanic ran diagnostics on the engine light through the OBD and came up with one error code
P2245 - o2 sensor - circuit low.
That would explain the slight increase in fuel consumption perhaps?
My Mercedes Benz dealership said it would be fine to drive until I next get it into them. (at least I have that in an email)