Motown7CLK

I own a 2001 CLK 320 convertible with just over 106,000 miles on it. Driven gently for over 5 years. Had the catalytic converter go bad at 60K and it was replaced under warranty by the dealer.

About two weeks ago my Check Engine light began turning on, and would stay lit for a few days of driving and then shut off again for a few days.

There's no loss of power, exhaust seems fine, mileage is fine, no roughness at idle or during acceleration.

A service technician told me that the light refers to the emissions system, so there might be something going on with the muffler, cat converter, or...

I haven't crawled under the car and don't feel like paying the $200 for an "investigative check" at the moment.

Any ideas?

Thanks!

SMARTSSUCK

Is it possibke that you left the gas cap loose?

velvet fog

CEL should be setting codes in the OBDII. Most auto parts stores will read those for free. Will at least tell you where to start. My 430 acted this way when the MAF went out.

Motown7CLK

Hi and thanks for the posts. I am aware of the "loose gas cap means check engine light goes on" syndrome and don't think that's it (if only life and life with my CLK was this easy...).

But what's the OBDII? On board diagnostic indicator i-thing? And MAF is completely foreign to me and I'd love a layman's translation.

Thanks,

Ron

velvet fog

STFF - Search the Fine Forums

MAF - Mass Air Flow sensor - common failure on 208's
OBDII - Onboard Diagnostics level 2. OBD records failure codes. There is a plugin below the steering wheel for the code reader.

Serndipity

Ron,

If not putting the fuel filler cap on correctly caused your CEL to come on, you just need to put the cap on right and after 3 drive cycles (going from cold start to full warm up) the CEL will turn off.

If not bring the car to AutoZone, Advanced Auto and they will read out the OBDII codes for free. The codes will provide more information about what fault is causing the CEL to be on.

Motown7CLK

Thank you all for the information!!

By the way, I originally registered on this site back in 2001 when I got the car and enjoyed it (the site) immensely. It's good to be back and I really appreciate the suggestions and the assistance.

Thanks!

Ron

platinumney

thank you motown for asking and id like to thank the rest of you for answering becuse im having the same problem i didnt know about the auto zone thing that will save a couple of dollars if i go to dealer knowing whats wrong and i can buy my own parts

Motown7CLK

Howdy all. To continue the mystery, as has been reported, the CEL seems to go off after three cycles of engine start (from cold start) to full warm, and then engine off, and so on, three times. Then it stays off for a while.

We just returned from a trip from SF area to Carmel for the wekend, and I ran the car when the CEL off cycle would take place during the bulk of my driving. Here's the deal: for the full ~120+ miles from SF area to Carmel, the CEL light stayed off, and then while we were down there and driving around it came back on, and then today (during an off cycle) it stayed off for the ~120 miles back home.

So my question is: is it really the MAF sensor, as many suggest, if it goes for such a long time with the light off, with no driving abnormalities noted? Maybe the computer just has to be reset?

Is this something that can wait till the next service in like 5000 miles (occurred a few weeks after a major service so yes I am concerned that there is a pinch somewhere but again it's not affecting the performance).

What do we think is happening?

Thanks!

Ron

velvet fog

Does it feel like the throttle response is different? The car definitely felt less responsive and felt like the transmission was acting funny. Gas mileage also dropped 3-4 mpg.

Sounds like you may just have a faulty gas cap.

Motown7CLK

Hi I am beginning to wonder... Drove the car to/from work today (about 30 miles each way) plus a few stops on the way home and no CEL. Yes, if I have to say it might be that with the CEL on it feels only the tiniest bit less responsive but it could be just my nerves having to look at (or wait for) that light...

On a good commute day I get about 30 mpg and if I did a normal commute with the traffic I am used to given where we are and got only 26 mpg I'd think there was glue in the engine (or another appropriate murdered metaphor).

Might change the gas cap (cheap fix! ha!) but so far it seems ok.

I really appreciate all of the comments and suggestions.

Thanks!

Ron