My wife's 1999 E320 lost power on her way to work. It did not die but, when you press the gas pedal the car does not accelerate but snails forward. Had the car towed to the Mercedes dealership and that is when the fun started.
The rep said that they had to change the Exhaust ($1500), the fuel injecter and some senors BEFORE they can diagnose the car.
Sounds strange to me. Another mechanic we called said that Mercedes are having problems with their exhaust and although there is no recall they are replacing them for free. Has anyone heard of that? Not to mention that this particular dealership is saying no.
I appreciate all the help.
Thanks.

 

Hi,
Sounds like the car MAY have gone into "Limp Home" mode.
This occurs when an emmission control fault occurs i.e. emmissions above legal limit.
If there is a fault the Check Engine / MIL light should have illuminated. If so the dealership should have interrogated the onboard diagnostics to determine the cause (DTC Diagnostic trouble Code) which is stored in the control unit.
It's quite possible that the exhaust and injectors are the problem but there is a large part of the story missing and without this info the story sound a bit iffy. Why do the garage need to change the exhaust / injectors?
If the exhaust has been working OK since 99 I suspect the story about MB having problems / recall is a load of rubbish also and the fact that MB are changing such old exhaust systems FOC sounds wrong. In Europe MB won't allow claims above 1 year on an exhaust (2 if you are lucky) since so many things can damage a catalyst which are beyong MB control. Wrong Gas, driving through water, impact damage etc.
What mileage has the car covered?
Let us know how you get on.

 

It's not JUST emissions faults that put the car in limp mode. For example, some tranny problems will do it without lighting the CEL. A dealership service dept. should know if it's in limp mode, though.

I thought cats were covered for longer periods than other components, not for running the wrong gas, driving through water, impact damage etc., but for manufacturer's defects?

 

Hi Lugnut.

I agree with you re Tranny faults but was responding to the fact that the garage had changed the exhaust, injectors etc.

I did state that there was inadequate info. in the post.

The MB situation may be different in the States vs UK but over here I have personally battled with MB regarding manufacturing / design defects in catalysts. At circa 50k miles on both my V6 SLK and V6 S Class the catalyst monolith has started rattling in its casing. Emmissions are fine, no casing damage and other than normal wet roads in the UK!! the vehicle has never been in any deep water.

My answer reflects the official MB answer I received. Parts in the UK are circa £1000 per vehicle so I run the vehicles complete with cold rattle. there are fine once warm.

Latest catalyst technology uses steel monoliths which overcomes this problem. Stuart

 

Well, I'm confused too. I was adding to your post, not trying to pick it apart.

If a cat was plugged or damaged to the point where it didn't function, then there should be an O2 sensor fault and an CEL light. I mean, their primary function is to monitor the cats. So I agree with you. However, an O2 sensor fault won't put the car into limp mode, as far as I know.

Maybe by "exhaust" they meant bad cats and by "some sensors" they meant fried O2 sensors due to the bad cats? Get those repaired and then see what happens, or "diagnose" further? Makes some sense.

Still, I wonder why they didn't realize it was in limp mode, if indeed it was?

And replacing the injectors? It seems they discovered a fueling problem that reduced power instead of limp mode.

 

Hi Lugnut.

Looks like the saying "Two nations separated by a common language" may have some relevance. I wasn't having a go either. PAX.
I wonder what the problem was and whether they fixed it?

 

I too is having sort of the same problem. Two days ago, I try starting my car, three minutes into the idle it shuts off. I restart it and it was fine. I drove for about five minutes then it shuts off at the stoplights. While driving it seems that while pressing the Gas pedal the car is not accelerating. After pressing it a few times then it picks up. This happen a few times while driving. It got so bad now that I often puts it in Netual and and rev it up while waiting at the lights.

I don't think it is the alternater, all the lights and instrument panel works fine.

I put a bottle of injector cleaner in a tank of gas but to no avail.

I suspect it could be the Gas pump or maybe a relay switch.

What do you all think.

 

Hi,

What model, age and mileage are you having the problem with?

Are there any lights ON on the dash?

Stuart.

 

It is a 1997 320E 170,000km. Before this problem started the check engine lights were on for a long time. I took it to the dealer and they check it and said it is no big deal not to worry too much about it. I took it to a second dealer and it was the same thing.

The stalling and shuting off and the no acceleration when pressing the pedal just started suddenly a few days ago.

I will take it to the dealer soon, but I wanted to have an idea of what it could be. Maybe it is something I could fix myself.

 

Hi,
Most of your symptoms suggest that the vehicle has gone into "Limp Home" mode. However the engine should not "Cut" so there may be more than one problem.

With a vehicle this age / mileage it could be any number of things causing the problem so I can't offer a magic bullet.

However the yellow MIL (Malfunction Indicator Light) or CEL (Check Engine Light) as it is sometimes referred to, is there for a reason. It lights up when a Power Unit (Engine / Trans) malfunction is detected which threatens EMMISSION legislation. The Engine Management Computer (EMS) is continuously carrying out checks to ensure Emmissions compliance and also carries out tests at "Start Up" to ensure electronic sensors etc are functioning correctly. When a fault is detected it is recorded in memory and dependent upon severity and other RULES it turns the MIL light on to warn the driver to take the vehicle for repair / inspection. (sometimes a transient fault has to occur x number of times before it triggers the MIL) In certain conditions the problem may be sufficiently severe / important that the EMS enters fixed parameters for fuel, engine revs etc (Limp Home) which resuls in an engine which starts but does not deliver the normal power / response to throttle. This feature is intended to reduce the inconvenience to the driver by avoiding leaving him stranded by the roadside whilst also minimising the extent to which emmissions legislation is exceeded whilst the vehicle continues to be being used.

Sometimes the light comes on for a seemingly spurious reason which once reset does not immediately reoccur (example a misfire at max revs) in which case cancelling/resetting the MIL light from ON to OFF may be appropriate. However if the light comes ON again almost immediately there is something significantly wrong. Not sure why the dealer stated that the light being on didn't matter. I live in the UK but I understand that you are unable to get your version of our yearly MOT test with the light ON. With each generation of on board diagnostics the rules which govern when the MIL light illuminates have been refined so as to reduce the incidence of spurious warnings.

When the light is ON an engineer (or DIY'er) can access the cause by scanning the onboard EMS with a scanner tool. This gives a Code Number which indicates the general area of what is wrong. e.g. Misfire on No, 1 cyclinder. It doesn't actually tell you that the spark plug or injector is faulty.

I hope this helps you understand something about what is going on and will equip you to have a more meaningful conversation with your dealer.

Stuartr.