Just purchased a 94 E320S w/ 92k on it. Had the car for 1 hour and the check engine light came on. Dealership fixed the issue the next day stating the engine was sending a faulty over voltage signal. 48 hours later the check engine light is on again. Anyone know of any electrical issues with 94 E320's? This is my first MB and the car is a joy to drive.

Thanks.

 

I just read an article from a MBCA technical reprint and it talked about checkengine lights. 98% of the time they are either a MAS sensor or an O2 sensor, or things like you mentioned or even a loose gas cap. I would have them check to see if there is a new fault code. That is really all you can do. The voltage signal could be from a bad O2 sensor and there are plenty of them on 90 plus Benz cars. Did they say how they fixed it or on the worksheet does it say what caused the faulty over voltage signal? Probably says from a check engine light. A dealer pulled that on me on another issue with my 99 C280 and I insisted they write out all the "cause, effect and cure." on any service work that is realated to check lights or other engine problems. Which they grugdingly now do.

 

Just talked to the dealership and they agreed to fix again. This time I will get more specifics on the issue and the fault codes.

Thanks.

 

Good, get explanations, of what they do. If your ever out of town and have the same problem and use a different dealer, then you have some info, on what was done already and could save some labor time.

 

Hi. I have a 96 s320. I'm having trouble passing smog and that my check engine light came on. The machinic said that it could be the gas cap, so I went and replace the gas cap, but it didn't solve the problem. Then I took it to the mercedes dealer, they said that there was problem with the valve or something and they made the check engine go away, but within a couple of hours later the check engine came on again. They fix it within that day. Did they really fix my car? Can anybody tells me what wrong. What else can cause the check engine to come back again?

 

opps! I spell mechanic wrong

 

they rest the code. but that doesnot fixthe problem!