Jovsky

I'm not really sure what the problem is but sometimes, not all of the time, my car's Check Engine Light turns on after having my car filled up with gas and/or I take my car to the freeway at 80 mph (short distance). After 2 days, the Check Engine Light will go off and by the time I take it to the shop for diagnostics, they can't find any codes. Any ideas?

Sathinas

Take it to a shop when the Check Engine light is on, then?

But if it only happens after you fuel up, I'd be willing to bet it will be an emissions related code. Something along the lines of P0442, Evaporative Emissions Control System.

0442 comes up when you forget to replace the fuel filler cap. I'm not saying it's 0442 for a fact, but it wouldn't hurt to get the code(s) pulled and/or start with replacing the fuel filler cap.

The CEL goes off after a couple of days because the computer doesn't see the problem after X amount of drive cycles.

If it were me, I'd get the codes pulled. Any Autozone, NAPA, O'Rilleys, (basically any National Auto Parts chain) should have an OBDII reader.

If the CEL is on and they can't find any codes, then you'll have to take it to an MB shop that has SDS and can pull MB specific codes.

Jovsky

I've been trying to bring it to the shop while the check engine light is on but when I am on the way to the shop, the light goes off and they could not find any codes. Maybe it needs a gas cap replacement. I'll try that first and see how it goes. Will update you on further development.

Thanks Sathinas!

Sathinas

It may be a gas cap, it may be a bad fuel tank pressure sensor, it may be a plethora of other things.

If the gas cap replacement doesn't fix the problem, don't throw parts at it. Hell, go buy a decent OBD II scanner and when the CEL comes on, read the code(s) with your new scanner.

A code scanner is always a good investment, IMHO.

nelson09

I had the same issue. CEL for a couple of days/off for a couple of days. 2 new 02 sensors fixed the problem. If it helps any Hyevon Motors ran diagnostics, got the pars and installed the for less than the parts alone would have cost me anywhere else. Good luck.

Jovsky

Thanks guys! Will try to buy a decent OBD II scanner to check the codes when the CEL is on. Thanks for the inputs and tips!

PaulyCA

Kept happening to me too. It was the gas cap. Smog station confirmed when they did the gas cap check as part of the smog check. I never did buy a gas cap, just started tightening the cap better after each visit to the gas station.

Jovsky

I almost forgot about this thread, but I solved the problem last July 10 by replacing the gas cap. I bought a MB OEM gas cap from the dealer for US$20. and the CEL did not light up again. Thanks guys for all your inputs!

brasil

Hi Guys,

I'm swooping in from the CLK W208 forum, but did a google search for "check engine light" on this site and found this thread. My CEL came on for the first time in the two years i've owned the car. The shop I took it to last in the Bronx charges $99 just to read the codes.

Is that how much most shops charge to read codes? I'm a computer guy and I know how trivial reading data off a device is and $99 seems like robbery to me. How much do the code readers cost? Is there a place in NYC that would do this for less or for free?

Any advice would be greatly appreciated!

C43AMG

Go to the Harbor Freight website.....dirt cheap !

brasil

you mean this harbor freight site? http://www.harborfreight.com/automot...stics.html?p=4

A quick search for "OBD II Scanner" on google brings up this page:
http://weoffer.com/obd-ii-scanner.html

I see the 38 pin connector for mercedes on that page for $14 (I don't know if the W208 uses 38 pin or not). The most expensive scanner on that page is not much more than the cost of 2 code reads at that repair shop. It's pretty obvious that buying one of these things makes a lot of sense.

So..... specifically which OBD II Scanner has someone on here bought and successfully used to read the codes on their car?

ohlord

you go into the 16pin port under the drivers dash
any of the 50-90 buck harborfreight units will suffice a lifetime of shadetree diy obd2 issues.
the real time data loggers like http://www.autotap.com/ go beyond basics and the site is a good read for learning about obd2 protocols and more.
$99 theysawzucommin
as always when you have the codes post them on the forum
most senior members know what they mean before they finish the reading the post.

"GOT CODES?"

brasil

Tonight I drove the car again to see if the CEL would go off, and it did! I had a feeling that was going to happen. Must have been something trivial like the gas cap being loose before my 300 mile drive home this weekend.

I'm going to definitely pick up at least a $99 level unit asap though so i can avoid getting ripped off only to find out nothing serious was wrong. I really appreciate all of the help on the forum!

Jovsky

Just in case the CEL turns on again and you decide to get a decent OBD II scanner, you can pull the codes meaning here: https://mbworld.org/forums/c32-amg-c...ror-codes.html

C230Ak

My '98 C230's CEL came on and the rpm drop to about 500 for a few seconds (this causes an unnerving shuddering ) when I come to a complete stop or slow down below a few mph.

I went to O'Reilly/Schucks and scanned it and came up with

"P0446, Evaporative Emission system vent control circuit"

Anyone here know what specific part of the evap system this refers to?