gab

havent driven the car in two rainy cold days when i started the car this morning the check engine light is on! I felt the car has some asychronous vibrating. What has gone wrong? should I drive the car to the dealer?

benzomonterey

did you check the gas cap? it will cause the light to come on if it is not tightened properly. Not sure about the vibration

Flashman

On a side note... I always found CHECK ENGINE lights rather amusing...

You car quits, and the CHECK ENGINE light comes on. Duh. What else would you check, the trunk?!? It would be more useful, with all that computing power in the car, if it just told you what was wrong "3rd spark plug cable bad, please replace".

Rick

MarkL

Most of the time, the engine will still be operable when the check engine light comes on. It can indicate many different types of problems, some more serious than others. As I'm sure you know, the MB techs can extract the specific code(s) that made the light come on. I agree it would be helpful to see a more informative message so the owner could know the severity of the problem.

gab

it turns out that engine reported 3 spark misfire!! does anyone know why? I never run on empty fuel tank

Rick

What....you thought Mercedes uses Macintosh computers in their cars? LOL :p [B]

Mike T.

That sort of thing has got to be extremely annoying - to have a driveability problem with a new car. I usually drive old beaters and never have had a problem like that with my present car - for 8 years and 130,000 miles - the car is nearly 14 years old now. Oh, and it's French, not Japanese...

Even my older car from 1966 runs like a top, no hiccups, no breakdowns, no check engine light. There's nothing like mechanical fuel injection by Kugelfischer...

The dealer should be able to explain the source of the problem in clear language, and explain what they have done to ensure that it does not happen again. The vibration you felt was due to a cylinder (or few) not firing properly. Do not accept the "unexplained intermittent problem" excuse. There is a real problem behind this. Good luck.

mbtech208

How did you find out what the code was? Did you take it to the dealer? What did they do?

And to Mike T.-
As unprofessional as an "unexplained intermittent problem" sounds, the fact is it DOES happen. There are sometimes when a car will have a "hiccup" once in a great while, and nobody can explain why. These are usually followed up by MBUSA issuing bulletins that say something like "We are aware of this complaint, but there is no fix at this time." Try getting a customer to buy that! Unfortunately, there's not a lot that can be done in a case like that.

Mike T.

Yeah, I know that with increasing complexity, there is an increasing likelihood of chaos erupting in an electronic system.

I should add here that my 1988 car's got a Bosch Motronic engine management system, so it's not exactly a low tech car either. It's been totally reliable, now with 155,000 miles on the odometer. THAT's what any expensive new car should be like.

I remain convinced that a dealer or indeed MB itself would never accept occurence of such incidents as normal, or indeed attempt to explain them away as simply being part of the everyday driving experience. This fellow's engine very nearly broke down, as he describes it, or it could have - this was not a loose gas cap.

Any new car should give 100% confidence to its owner - that it will do what is asked of it in all circumstances.

Problems such as this in a new car are unacceptable. If the manufacturer admits that there is a problem but no solution, it indicates poor engineering, poor assembly, substandard quality of parts or incompetent management.

So my message to the owner of this car remains: push the dealer and manufacturer until they can explain the problem and rectify it to your satisfaction. Also, document the problem and your contacts with the dealer and MB in writing, in case you need to eventually use the Lemon Law. I think you won't have to though. I'm a naturally optimistic person

vadim

If you start your car (cold), run it for a very short time (like 30 seconds), and then shut it down before the engine reaches the normal operating temperature (i.e. to clear the driveway etc.), it may subsequently develop a so-called "lawnmower syndrom", which results in hard starts and rough idle and sometimes misfiring. Maybe that was the case?

Anyhow, if it happened only once and never reoccured, I wouldn't worry about it. There are so many variables and factors affecting the ECU's diagnostic algorithms, it might have gotten confused by some rare combination thereof... Then again, stop-and-go traffic is far from being an ideal operating mode...

Flashman

Forget fancy electronics for a while...

If a single cylinder is occassionally misfiring... that is usually a pretty straightforward indication of a bad spark plug cable. It is the same effect you get when cables get old. Maybe this specific cable was in the parts bin a little too long before getting installed.

Rick