The 'check engine" light on the dash comes on about once a week for a duration of a day or so. Is there any simple inexpensive test equipment a D.I.Y. can buy to diagnose or troubleshoot the problem.

I understand the “check engine” light monitors at least one hundred functions.

Someone said that it maybe an O2 sensor. There are four on the car.

Thanking you, in advance, for your assistance.

mike

Make sure your gas cap is on securely. That was happening to me on my 98 E320. I noticed it right after filling up with gas. Someone on this site suggested that and it solved my problem

__________________
Donwo
1999 SL 500 Sport (30K miles)
1998 E320 (SOLD)
1989 560SL (SOLD)
1987 300E (TOTALED)
1986 300E (SOLD)
1984 300SD (SOLD)

If the gas cap is tight and light still on, buy a OBD II diagnostic hand held. It's about $100 and plug it into the diagnostic port under the driver dash. It will read the code and tell you what's wrong. Car parts stores like Kragen, Pep Boys, Auto zone all sell these.

Many small private shops will check the code for you for free or a small fee since it's a 5 min job. Dealer charges 1 hr of labor which is usually over $100.

I bought the OBD II code reader for $129. at Pep Boys and the reading said "P0173 Fuel Trim Malfunction (Bank 2).

The gas cap fits tightly and appears to seal okay.

I'm now trying to find out the exact explanation of this code.

Thanks "donwo" and djantlive" for your response and advise.

mike

Here's the problem. Reading codes is the first step in diagnosing the problem, and not definitive. It will point you in the right direction, but that's it. It usually takes some experience and the SDS (Star Diagnostic System) to boil it down to a single cause.

In this case, your code might be leading to an Air Mass Meter, which generally pops codes P0170, P0171 and P0173.

Here is a list of all the codes for future reference:

http://www.whnet.com/4x4/mb-dtc.txt

__________________
John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif