2002 W203 C240 idle problem...
 

A friend of mine brought his 2002 C240 over today. He's stumped. The car has an occasional rough idle. I experienced it. It sits, smooth, and then suddenly the idle falls below 500, and feels like the motor mounts have given out. It's rough, and stays that way for some time. Then, it returns to normal.

He's taken it to the dealer over and over again, and they ignore it. There's no MIL or anything showing on "malfunction" screen. No codes...

It really feels like it's going to stall. I've had a few C240 loaner cars, and none of them felt like this. I called my aunt, as she has a C240, and she's never had this problem.

If it were misfiring, you'd think it would record a code.

He's hoping to get some sort of info to take with him on his next dealer visit.

Had the same thing on mine, but at partial throttle. Put the problem to the experts on this forum and got extensive possibilities. Search under my screen name, ducatista, and you should be able to find the thread.

Eric.

i'd return the car if i were your friend!

He needs to contact the regional service representative and raise #$!!. Also keep all repair statements and check into the lemon law. Start telling the regional service rep how many more repair calls he gets before the lemon law conditions are met.

The problem could possibly be flap actuators for the resonance system. Once they determine what it is and replace the offending part, it will be good as new. Been there, done that!

Good luck,

In Canada, our beloved Brian Mulroney dismantled what little remaining consumer protection and anti-monopoly laws were left on the books. No lemon laws. Business can pretty much do what it likes to consumers. Our laws are called "buyer beware, and so long sucker..."

He's since been back, and it did it, right at the dealer. They hooked the scanner up to it, and it showed no codes.

No codes = no repair. Go home. He mentioned some of the potential problems that I found here in the archives, and they explained that they are Mercedes mechanics, and he is not, and so what he says means nothing to them.

He called the Zone rep this morning, and it sounds like he might be getting somewhere with him. He is arranging to come to Edmonton (he's in Calgary) and see the car first hand.

If this is resolved, I'll post it so that other W203 owners might be saved a little grief if the same problem arises. It's probably going to be simple to solve if the durned dealer would really examine the problem...

Otherwise, he does love the car...

Well, he switched dealers. The "new" dealer has indicated there is a problem with a car. They have given him a loaner (an E320 4-matic! wow) and said they are going to keep the car for a few days to figure out the problem. They said they've seen one other car do the same thing, and are going to try the same solution.

When I get more info, I'll post...

I went through a similar situation with my '96 E300D. The problem the dealer had to deal with was not having authority to replace certain parts. The regional rep knows no more about it than the dealer, but they can authorize paying for parts that they can install in an effort to fix it.

In the dealers defense, my problem was intermittent, so they had to drive it a bit before it acted up for them. Having worked on all sorts of electronic and computer equipment over the years, I understand the problem associated in troubleshooting an intermittent situation.

If they have taken the car for a few days, I fully expect that they will find and cure the problem.

Good luck,

Just got off the phone with Rob, and the dealer thinks they've found the problem. They let the car idle for a while this morning, and sure enough it started running rough.

Still no codes.

Rob went by not too long ago. They had taken an ignition module of some kind out, and replaced it. The tech replaced the plugs while he was at it, and checked the plug wires and other ignition parts.

When he was there, it was running like a top. The service manager is going to drive it over the weekend, to make sure they've nailed it.

They can't explain the "no codes" condition, but seem to be working hard to fix it regardless. This morning, quite quickly, they determined it was bad "spark" and not a fuel delivery problem. Then he started at the plugs and worked his way back...

I'm just sorry that the tech will be paid "warranty" rate for this fix. Looks like he found the problem quickly and without much fuss. Didn't need a "code."

Rob's owns a gourment foods manufacturing company, and is going to drop of some goodies next week. I think the dealer made a new customer...