After driving the long-term 2008 Mercedes-Benz C300 for a few days I looked down and saw the check engine light next to the gas gauge. My first thought (as always when I see this light) was, "Hmm, I hope it's nothing serious." So I drove with a notably lighter foot until I got home, then -- as instructed by the light -- I endeavored to check the engine.
But that's easier said than done, as the hood release on the C300 is literally hidden inside the dash. No, not under the dash -- inside. Perhaps it's a safety issue, as nobody wants their knee jamming into a release lever during a serious impact. Still, a little indication that it's down their, in the form of a "HOOD" label and/or arrow, would have been nice. As is, I spent several minutes searching and pawing the lower dash before finally getting out of the car, leaning way down and scanning the driver's footwell.
After (finally) opening the hood I looked for the oil dipstick to make sure the most vital of fluids was in the safe zone. Then I looked some more, and then -- just for fun -- I looked some more. Can you see the desired service point in this photo?
I'd almost given up when I happend to glance back at the middle of the firewall -- essentially the hardest part of the engine to reach (yes, even with the double-jointed hood). EUREKA! I spotted a sliver of yellow plastic and went in for a closer look. This location reminds me of the dipstick location in the Pontiac Solstice. Because that engine comes from the Cobalt, and was thrust into the Solstice during the car's development, you have to wedge your arm between the block and firewall to check the oil. Not sure what Mercedes' excuse is...
Upon inspection the oil level seemed fine (I think -- like our long-term BMW M3, the stick isn't very easy to read). I also checked the coolant and brake fluid levels -- all fine. Hmmm.
Then I went to put gas in it and, ironically, couldn't because the gas station's credit card reader was on the fritz. But I didn't discover this until pulling up to the pump and removing the gas cap. So I put the cap back on and drove away.
The light is no longer on.
Yes, I know this is the most common reason a "Check Engine" light comes on, but I think automakers should literally put a "Check Gas Cap" light in their cars so people can know when there's really a problem or not. BTW, the car had been driven over 100 miles without the light on after the previous fill up. And the cap seemed fully secure before I removed it.
I'm officially changing the term "idiot light" to "idiotic light."
Karl Brauer, Edmunds.com Editor in Chief @ 11,625 miles
estreka says:
02:08 PM, 06/30/08
But if automakers developed a "Check Gas Cap" light, franchise owners wouldn't rack up those $35 diagnostic fees.
Quite honestly, I'm surprised the light went off. Usually you have to get the light manually reset (and they won't do that without the aforementioned diagnostic test).
joefrompa says:
02:10 PM, 06/30/08
I second one thought in your post: It's amazing to me that "check engine lights" still exist.
This is 2008. We have multimedia interfaces, iPod integration, CD-title reading, etc. etc.
Why is it that we only get a small yellow/red lit symbol to tell us there is something wrong with the functioning of our vehicle?
How about the car read the problem and instead of throwing "a code" it actually spell out the problem in some sort of display. I.e:
"Gas Cap loose or related problem"
"Engine overheating or related problem"
"Cylinder 3 misfire or related problem"
"Trans shift selector not functioning"
"Oxygen sensor reading out of range"
"Coolant level below minimum, Add 50/50 recommended coolant and distilled water"
"Brake fluid nearing end of serviceable life, flush and replace soon"
I mean, come on. This would be great information and instead of "yellow light means you can keep driving to the nearest dealer, red light means stop immediately and tow" you could actually assess the situation.
It's like customer service. Give the customer more options and let them select the level and depth they would like.
But hey, that might require integration between the driving parts and the infotainment system, and Lord knows that might require the manufacturer to work with their outside vendors in a collaborative way.
Joe
cah11705 says:
02:12 PM, 06/30/08
well at least you now know where the dipstick and hood release are
toyzm says:
02:19 PM, 06/30/08
This is funny. MB tries to make their customers feel special by having some idiotic placement.
the_big_al says:
02:26 PM, 06/30/08
these days, on high end cars, a simple check engine light is retarded. Just plain silly. Especially with vehicles with Nav screens. That multifunction nav screen that also double as an interface for everything from the climate control to the windows switches, why couldn't they use that screen to also post vehicle diagnostics??
(doesn't Onstar do this already though???)
m_thrizzle says:
02:32 PM, 06/30/08
BMW does have a separate warning light if the fuel cap is not on correctly. I would have thought MB and other German brands would have the same thing.
At least the CEL went off.
louiswei says:
03:23 PM, 06/30/08
At least the Merc has a dipstick, where is one in the 3er?
banhugh says:
04:01 PM, 06/30/08
the light is the most ingenious way for dealer service departments to make tonnes of money. A 10 minutes code scan costs about $100 at the dealer. So I disagree with the term idiotic light. I would suggest the money pit light.
mlowery85 says:
04:40 PM, 06/30/08
If I leave the gas cap loose on my 2007 Civic Si, it literally says "Check Gas Cap" in the MID display in the dash that also houses the odometer and outside temp and oil life gauges. +1 for Honda innovation.
ahightower says:
08:49 AM, 07/ 1/08
"as instructed by the light -- I endeavored to check the engine."
Ha! Good one. Obviously you're not supposed to take it so literally. They don't want YOU to check the engine... they want your certified MB dealer to check the engine. And to charge you $100 for the "service".
I agree with others. Can't those retarded i-Comand-MMI-LMNOP systems display a more descriptive note?
mercedesfan says:
11:47 AM, 07/ 1/08
I am shocked that the car has a dipstick, the previous generation (C320 at least) had an electronic means of measuring oil level like every other Mercedes on the market. Also, COMAND does display a lot of information about the problems with the car, you just have to dive into the menus to find it. I am honestly not certain if it has an error for the gas cap, but just about every other error comes up by name if you head to the malfunctions menu in COMAND.
saxdogg says:
06:14 PM, 07/ 1/08
My 08 GMC Sierra has this light as well. CHECK GAS CAP!
How can I get a job driving these cars and writing about them? I'll use the correct "their," "there," and "they're," I promise.
JP
bimmerjay says:
11:38 PM, 07/ 1/08
"Can't those retarded i-Comand-MMI-LMNOP systems display a more descriptive note?"
iDrive does provide error message similar to what joefrompa outlined. For example, in the cluster the check engine icon and warning light will come on, and iDrive will pop up a message like "Transmission malfunction. Please have the vehicle serviced as soon as possible. You may continue to drive with reduced performance." or "Transmission malfunction. Please stop the vehicle in a safe location and contact Roadside Assistance." It won't tell you cylinder #3 is misfiring, but it will give you a bit more detail on the nature of the problem and the recommended course of action.
One time I was driving with the cruise control engaged on the freeway, and went over a bumpy, slippery bit of pavement. It was enough for DSC to blip and I got an angry gong and an iDrive message, "Due to slippery road conditions, the cruise control has been disengaged. Please drive with caution." Or something along those lines. Of course I just re-engaged cruise. :-)
Remember that most consumers would have no idea what to do with substantially more info. They'd still take the car to the shop, point at it and say "fix it".
wants2sk8board says:
01:41 PM, 07/31/08
i agree with that they should have it on the higher end cars. My $19,000 Ford has it and that is standard for that trim. If Ford has it then why not a $35,000 MB?
12rings says:
12:47 PM, 08/21/08
We are all assuming that the dealerships want to make money but actually it would save the manufacturer a bundle if we could diagnose problems ourselves. A large majority of the cars on the road are under a warranty, so it only costs the manufacturer more to diagnose each and every code an owner brings to them (Dealers bill the manufacturer for warranty work).
Is this a case of the manufacturer doing their dealers a favor?
Bimmertech says:
05:56 AM, 02/ 2/09
I am surprised as well that there even is a dipstick. Many higher end vehicles are moving away from that these days.... Very annoying.
I have to say though, giving too much information instead of 'just a CEL' can be dangerous. BMW, as someone pointed out does give a little bit more but still errs on the side of caution.
If the exact fault were displayed I fear what would happen with non mechanical people... Or people who like to think they are mechanical but really shouldn't be allowed near tools.....
I agree it's a money maker. But on the other hand there is something to be said for actually diagnosing problems instead of just throwing parts at it, which gets even more expensive than your diagnostic charge if you 'guess' wrong. And someone who knows nothing bout cars may ignore a fault that sounds innocuous but isn't.
In some ways the manufacturers are protecting us from ourselves. If you are knowledgeable about cars you can pick up a cheap obd code reader. For everyone else too much knowledge in the wrong hands can be dangerous....
Just my humble opinion.
samuraidad says:
12:59 AM, 11/14/10
I realize this is a little after the fact but better late than never. when it comes to the check engine light two types of codes are stored in the on board computer. When the light stays on even after the vehicle has shut down you have a hard fault that has not corrected itself and has set a code or codes in the OBC. If the light goes out you have a soft fault meaning a code has been set but the condition has corrected itself. Mercedes does recommend checking the gas cap and the light may go out but was it from the corrections of the fault and the vehicle is not doing anything to keep the light on or was it the gas cap? Get a dealer or someone to scan and check the system you will be surprised what you find