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Hi I'm hoping someone has an idea what might be going on with my C240. I purchased a 2002 Mercedes C240 Elegance last October with 313,000 kms, automatic transmission. It happened the first time about 2 months ago. After I come to a complete stop and then press on the gas, nothing happens. I'll be pressing it all the way to the floor but the car won't move, won't rev, nothing. It's as if it's in neutral. Then after 10-15 seconds the accelerator catches and the car will go. It happened a few times on that drive home but then the car was fine. The next time it happened I was almost out of gas, I filled up the tank and the car was okay again. The problem however has continued to get worse. I noticed for some reason when I put the AC on, it makes it a lot worse. The car runs a lot rougher, so rough it would even shut off when idling. Two weeks ago it happened while I was getting on the highway. It's like there's a complete loss of power and the car just dies. But once again after pressing on the gas for 10-15 seconds, finally it catches and will go. I was able to get the car back home but every stop it would die and the battery/alternator light would come on. Anytime the car shuts off, I can turn it back on again no problem and it will go (sometimes with the hesitation, sometimes without). After a couple days I tried the car again and it started fine, there was no battery/alternator warning light. I tried to drive it to my mechanic's garage but it shut off again when I was at a red light and I had to get the car towed the rest of the way. My mechanic changed the air filter and cleaned out the fuel injection system. They said the car was running fine and I could pick it up.

I went to pick up the car and 5 minutes into the drive home it happened again. The car felt like it was running a lot better, it was idling much smoother than before. Then as soon as I plugged my phone charger into the power outlet, the car shut off 5 seconds later. Also right before it died when I was getting on the highway, I'd pulled over to make a phone call for about 25 mins and turned the car off but my charger was plugged in. Same thing for the first time it happened, I was pulled over talking to someone for 10-15 mins. My mechanic said the battery is fine (not sure if I trust him anymore) and I don't think it's the alternator. From what I've been reading it sounds like a problem with the mass air flow sensor or crank position sensor. My mechanic said no codes came up when he scanned the computer which is why I'm leaning more towards the MAF sensor. I'm just wondering if a failing MAF or CPS sensor could be made worse by plugging something into the cigarette lighter? I should also mention when I got the car the power outlet was not working and I had to replace the fuse. I had absolutely no trouble with this over the winter, it only started happening the past couple months. Please help as my car has been in the garage for 2 weeks now and I feel it's a much easier fix than my mechanic is making it out to be. Thank you!
 

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CH4S Admin , Outstanding Contributor
1985 500SEC, 1991 190E 2.6.
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Hi I'm hoping someone has an idea what might be going on with my C240. I purchased a 2002 Mercedes C240 Elegance last October with 313,000 kms, automatic transmission. It happened the first time about 2 months ago. After I come to a complete stop and then press on the gas, nothing happens. I'll be pressing it all the way to the floor but the car won't move, won't rev, nothing. It's as if it's in neutral. Then after 10-15 seconds the accelerator catches and the car will go. It happened a few times on that drive home but then the car was fine. The next time it happened I was almost out of gas, I filled up the tank and the car was okay again. The problem however has continued to get worse. I noticed for some reason when I put the AC on, it makes it a lot worse. The car runs a lot rougher, so rough it would even shut off when idling. Two weeks ago it happened while I was getting on the highway. It's like there's a complete loss of power and the car just dies. But once again after pressing on the gas for 10-15 seconds, finally it catches and will go. I was able to get the car back home but every stop it would die and the battery/alternator light would come on. Anytime the car shuts off, I can turn it back on again no problem and it will go (sometimes with the hesitation, sometimes without). After a couple days I tried the car again and it started fine, there was no battery/alternator warning light. I tried to drive it to my mechanic's garage but it shut off again when I was at a red light and I had to get the car towed the rest of the way. My mechanic changed the air filter and cleaned out the fuel injection system. They said the car was running fine and I could pick it up.

I went to pick up the car and 5 minutes into the drive home it happened again. The car felt like it was running a lot better, it was idling much smoother than before. Then as soon as I plugged my phone charger into the power outlet, the car shut off 5 seconds later. Also right before it died when I was getting on the highway, I'd pulled over to make a phone call for about 25 mins and turned the car off but my charger was plugged in. Same thing for the first time it happened, I was pulled over talking to someone for 10-15 mins. My mechanic said the battery is fine (not sure if I trust him anymore) and I don't think it's the alternator. From what I've been reading it sounds like a problem with the mass air flow sensor or crank position sensor. My mechanic said no codes came up when he scanned the computer which is why I'm leaning more towards the MAF sensor. I'm just wondering if a failing MAF or CPS sensor could be made worse by plugging something into the cigarette lighter? I should also mention when I got the car the power outlet was not working and I had to replace the fuse. I had absolutely no trouble with this over the winter, it only started happening the past couple months. Please help as my car has been in the garage for 2 weeks now and I feel it's a much easier fix than my mechanic is making it out to be. Thank you!
Welcome.
Scroll down the forum index to W203, your chassis.
Please make sure to complete your profile (click 'User CP' on top) with car mod and location.
BenzWorld is an international forum and Daimler Benz made different versions of same model cars for different Countries.
So to get relevant advice, location is important.
Cheers
 

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Coupe/Convertible Forums Moderator
CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Try this procedure below. It's sometimes erroneously called the TCU reset, but it actually syncs the rive-by-wire accelerator pedal and throttle body:

1. Make sure everything in the car is turned off and closed.
2. Turn the key to position 2 so all the dash lights are illuminated.
3. Press the accelerator fully to the floor, depressing the "kick-down" button.
4. Hold he pedal for 5 seconds and continue to hold it down.
5. Turn the ignition switch back one click to position 1.
6. Release the accelerator pedal, but leave key position 1.
7. Sit quietly and wait for about two minutes - do NOT open or turn anything on.
8. Listen for a "click" or "ping" noise form the dash.
9. Start the engine and drive the car for at least five minutes.
 

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'03 C320 4Matic Wagon
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Bumping this thread to ask a question about the above procedure:

After #8 above, the key will be in Position 1. Before starting the engine, should one turn the key back to off? Remove it?

Alternatively, once the ping/click has been heard after the 2 minute wait, should one simply turn the key from its current Position 1 to Position 2 and beyond to start the car?

Thanks!
 

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Coupe/Convertible Forums Moderator
CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Yes, in step 8, the key is in the ignition, position 1. So, when you hear the ping, just turn the key to position 2, then to start and then go driving.
 

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2001 C240
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Aloha Johnny,

Congrats on your ownership, handsome car! I like working and currently am restoring/updating electronics (2001 C240), the body of mine is run-down a bit but its all cosmetics. After-all what good is a beautiful car, if its sitting on the side of the road broke-down...

First - Are you doing the job yourself, if you don't have one already get yourself a OBDII scanner. (The scanner will help aid you in trouble-shooting.) Though most of the repairs up-until three months ago was done by myself with-out one. (I managed to knock-off four pages of Star diagnostic codes.)
 

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2001 C240
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Aloha Johnny,

Congrats on your ownership, handsome car! I like working and currently am restoring/updating electronics (2001 C240), the body of mine is run-down a bit but its all cosmetics. After-all what good is a beautiful car, if its sitting on the side of the road broke-down...

First - Are you doing the job yourself, if you don't have one already get yourself a OBDII scanner. (The scanner will help aid you in trouble-shooting.) Though most of the repairs up-until three months ago was done by myself with-out one. (I managed to knock-off four pages of Star diagnostic codes.)
 

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Coupe/Convertible Forums Moderator
CURRENT: 2011 SL550, 2011 C300 FORMER: ML350, CLK550 Cabriolet, C240, ML320, 300TD
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Thanks! I had the whole thing wrong -- meaning that I listened and listened and heard no "ping"!!
So you hear nothing? It is a very faint sound coming from the instrument cluster/dash area. It's sort of a click/ping noise. It's almost like the sound you hear when hear that last little bit of static as the tubes in an old amplifier finally power down (if you are old enough to remember that!). It is very faint, so you may not hear it if there is any ambient noise.
 

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It's your fuel pump. Know the a late post, but sharing anyway.
In the engine bay, you will see a valve on the left ontop of the engine. Looks like a tyre valve , with ignition on (warning, this is dangerous) get a big cloth and a long screw drive and push the valve, use cloth to catch fuel. Should come out like a rocket at 4bar+ if it's a bit week it's your pump.
If you. An get a test kit for fuel pressure then do so, Google what it should be. New pump is easy to replace. It's a common fault as well.
 
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