Check Engine light
 

I have a 1994 E320. The check engine light has come on. What can cause this?

When the Check Engine light is on, the cars computer will record & store a Fault Code.
This Code can be retrieved with a Scantool.
You will need to find someone ( M-B dealer if necessary ) to do this.
They should then be able to tell you what the problem/Cure is. ;)
And before anybody tells this new member to build a " Code Retrieval Tool ", I don't get the impression it is within his/her capabilities !

Go to Autozone and get the code scanned for free :).

Did the CEL come on before or after visiting Jiffy Lube mentioned in your second thread?

Wow, what a great thread! It just started and we've already got an assumption that the poster can't read the fault codes, that Autozone can for a 94 model, and that Jiffy Lube, from some other thread, may have caused damage.

kaylanakrishna - you can read the fault codes yourself from the diagnostic control unit located under the hood near the battery. The procedure is pretty simple - see this thread for more information...

http://www.peachparts.com/shopforum/showthread.php?t=71814&highlight=W124+code

You can read/reset the check engine light code from the diagnostic control unit near the battery.

Wow! awesome site!! So many replies. Thank you guys.

I am a new owner and have never had a Mercedes before. I am a totally newbie and being to the US, I don't even know how to maintain tire pressure. Before you all start laughing ... we get full service at no cost back in India.

I will check the things all of you helpful people suggested. I did not there is a way to read the fault code without going to the service station.

I will post what I find.

CEL was on before I went to change the oil. And since the car has bottom plate, I did not see an oil drip when parked.

Thanks,
Kalyan

EDIT: I think I am going to go in to Autozone to diagnose for now, if they offer it for free. At the moment, I am not sure I can do the self help steps confidently. I will post back what I find out.

Well, a few simple facts on your cars CE lamp warning.

First of all, a CE warning lamp activation is to let the driver know that a fault has been detected by the Emmissions control module in your car. The CE lamp does not store a code , it simply alerts you that the Emmissions Diagnostic Module has detected a system fault that will adversly effect the cars emmissions output beyond the Standard DOT legal mandates and that this fault/s has been recorded/stored in the Module and can be retrieved in the form of a Flash Formated code.
Secondly, you do not have to get a scanner or go to the Dealer to get this stored fault code. Your particular chassis has a built-in code access initiation LED/SW right in front of the battery that allows the owner to find out what the offending code/fault is.
SO, you do not have to build a tool or any of that jazz, b/c Mercedes has already done that for you...:)...it is a Standard Feature that comes with the car.
But, how does one do this code access ?????
Simple.... There is a small rectangular Black Box in front of the battery..[ this is the owner access Diagnostic Box]..lift the lid and press /hold the button in for 2 seconds and release it....[ like one would do with setting a clock or any other digital home device ] ....upon release, the little red LED lamp next to that button will Flash back the code for you. You just count the amount of Flashes and post that info and we will tell you what this neat little Detection Device has found to be out of Normal .... do this a couple of times in case there is more than one stored code. Each code will have a different number of Flashes, in sequence.............so, you may find that you have 4 flashes the first try , and maybe 5 on the second try...you will then post for us that you have found the codes to be 4 and 5 in this example.
That's all....simple.

Now , if you had some serious Engine mangement problems [ like skipping and No Start, etc], or maybe an operating system failure, we could also tell you to how to build a Led tool to diagnose those OTHER modules on your car from that same BOX...but they have NOTHING to do with a CE lamp, so we will not go there or do that as your concern is only the CE Warning lamp.
...but if you did have serious other operating problems , we would go so far as to let you know how to do that also. [ with a simple homemade tool]

And Autozone reads only OBDII codes but your car does not have OBDII, which is, with a few exceptions, 1996 and later models.

This is correct..
..and your car is OBD1 and is the last vintage to have the owner access built-in Flash-Code retrieve system...many do not realize that feature b/c they own OBD2 cars..... which is Digital Coding and a differently accessed system.
Thanks for mentioning that, Dean............

I don't even know how to maintain tire pressure.

That's what I thought.
How is that Mr. deanyel ?

I never knew that. Does this mean that you need the very expense code readers like the dealer has in order to be able to read the codes on newer cars?

No. OBD2 is a simple plug under the dash.
You can get by with a standard OBD2 scanner from any auto store...

Short $$$$.

I may be missing the point but I have a feeling the tire pressure statement was tongue in cheek. Regardless your assumption that he would not be able to build a code reader, true or untrue, was errant. A code reader is not necessary to read codes on the DM. We should strive to at least give the poster a fighting chance to do it themselves - as the thread fortunately does subsequently.

I believe him, when he says he doesn't know how to check tire pressure.
Furthermore, the way his original question was phrased
" The Check Engine Light comes on, what can cause this? ", gives me every reason to believe he is not " into cars ". :rolleyes:
Hence my comment about not even suggesting to him how to build a code retriever!