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Mercedes-Benz C-Class Maintenance and Repair



  • My battery is draining all of a sudden. I pull all the fuses under the hood and in the inside compartment. I hook a light to shut off if i pull the right fuse. The problem must be a direct drain to the battery. i dont have a clue.
    Merc 2002 C320
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,504
    Have you tested the battery itself? 5 years is about lifetime.

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  • heyvanheyvan Posts: 1
    W202 Power Seat ('94 thru '00 C-Class) Intermittent or inoperative power seats (especially those with passenger-side power seat option)

    Caused by failure of Convenience Feature (CF) Relay K24

    This relay is located in the trunk under a plastic cover between the spare wheel and the seatbacks. To access it, remove the carpeted cover over the spare wheel and then remove the black plastic cover held by three large flat screw-on nuts. The relay lays horizontal on the right side. It has two very large wires attached (red and pink). It unplugs from the harness, but the clips holding it in will have to be pried away from the relay.

    The Mercedes Part Number is molded into the cover. It probably isn't as expensive as some of the other MB relays, but unless it has been redesigned, it will just fail again in a few years or less. I suggest repairing it or asking an electronic tech friend to help.

    If you are capable of soldering PC boards, the relay can be repaired easily. Using two small round-blade knives, pry off the relay cover. Examine the PC Board near the plug-in base at the center. The solder connection from Terminal 2 to the N/O contact becomes de-soldered at the relay due to high current heating the etch. I suggest scraping off all the green solder-resist between the relay contact pad and the plug-in pad (only about 1/8") and flow solder over the whole area between the two points. That helps dissipate the heat. Usually that is the only solder connection that is bad, and the relay can be re-assembled.
  • Well here is the latest. I unplugged the seats just to see if that was the problem. the slow drain continues. I bought a new battery. same results just take a little longer. I am open for suggestion before i go and get robbed at the dealership.
  • sdavsdav Posts: 1
    I have the same problem with a C280 with parchment MB_tex. The dealer just told me any leather cleaner --sent someone to get it and he never came back.
  • i think you were correct on it being the passenger side seats. I will try to replace the relay nect thanx again.
  • the ESP light comes on every other day. sometimes it will come on everyday then it will not come on for a week. any suggestion.
  • jrct9454jrct9454 Posts: 2,363
    If you're driving a W203 C [2001-2007], check with your dealer for a TSB [Tech Service Bulletin] that involves replacing some electrical connectors in the engine compartment. There is a known problem there that is easy to fix, and often results in spurious ESP warnings.

    Restarting the engine will often make the light go out for awhile, but in the end, it will drive you nuts. You really need to get to a dealer to fix this problem - there are no "home solutions".
  • Mercedes changed out a vibration sensor in the transmission when this happened to me. Actually my car would shut off completely and then restart itself with the ESP light staying on until I restarted the car.
  • jrct9454jrct9454 Posts: 2,363
    Different problem.....I never had the car shut off by itself.
  • I have a 2000 C230 Kompressor MB that does the same thing. Periodically the ESP/BAS light will come on. It will either go off by itself eventually while driving or when I turn the engine off and later start the car it will be off. I have noticed that it tends to come on when the weather is rainy. Perhaps the slick pavement?
  • Update to my windshield wiper problem.
    Then MB tech replaced a wiper sensor and a relay switch. Works fine now.
  • jrct9454jrct9454 Posts: 2,363
    Yours sounds like the connector problem - have you asked a dealer about it? The moisture in the air can affect the connectors.
  • Got two things I'm trying to track down.

    Its a 2002 C230 (C-Coupe...important to note for item #2)

    #1 is that in (yellow) turn signal lights that are in the passenger's side mirror, I have two bulbs out (middle two)...assumption is that they're simply burned out and need replacement.

    Q: How the heck do I gain access to them to change out these bulbs? It looks like I can pull the mirror rearward (against its spring), rotating it around 90 degrees, but doing so doesn't seem to provide obvious access for service: is the next step to somehow disconnect the tension spring (and not lose it) to then unscrew the hinge mount to disconnect the entire mirror assembly* from the car...?

    (* - except for the wiring harness)

    #2 seems like a bad electrical ground problem. The radio plays fine (no static) under normal conditions, but if I hit the rear window defogger switch, I get a strong static over the radio.

    Defog seems to still work fine (mirrors & rear window). Dealership took a look at it around a year ago and said something to the effect that the suspecte culpret was the wires in the hatchback's rear window glass and to fork over $1000 please. An independent garage suggested that it might instead be the radio antenna's amplifier, which is hidden somewhere in back, but he didn't mention where (headliner?).

    Q: opinons or assessment of the validity of these 'troubleshootings'? And if its simply a bad electrical connection, if I can track it down & do it myself. To that end, where to go look for bad connections?

    Q2: In bending back the outside mirror for #1, I realized that the static could be from a bad ground anywhere in the defog loop, which includes both of the outside mirrors. Inside the mirror assembly, I noticed two wires connected to the top of the glass mirror, but they look suspiciously tiny for a heating circuit...IIRC, it was two very thin gage wires that were connected to the top edge of the mirror glass - - are these more likely to be for the auto-dimming circuitry and I need to keep looking further to find the ones for the defog circuit?

  • vivid1vivid1 Posts: 24
    Answer 1: On the end of the lense, there is a tab where the lense pulls out. On older models, you have to remove the mirror and go in that way.

    Answer 2: How often do you use the rear defroster? If not a lot, I would just live with it or listen to a cd when it is cold out... Although, it does sound like a wire touching. Pull off the dash face plate and have a look around.
  • On the end of the lense, there is a tab where the lense pulls out.

    I thought I saw a lip on the clear plastic there; will take a peek. Any idea on the model year break-point for when they went to this configuraiton?

    How often do you use the rear defroster? If not a lot, I would just live with it or listen to a cd when it is cold out... Although, it does sound like a wire touching. Pull off the dash face plate and have a look around.

    I'm in Northern NJ, so needing to use the defog is a pretty frequent in colder winter months, and during a snow event when you get stuck in stop-n-go traffic, the lack of a rear wiper makes using the rear defroster a near-constant requirement for the whole trip home.

    I hadn't thought about checking out the radio-in-dash end of things, as it plays fine under all conditions the rest of the time (no interferance from windshield wipers, etc), but I'll add it to the checklist to be thorough.

  • vivid1vivid1 Posts: 24
    The models that you have to go in through the mirror is the W202 (1995-2000). W203 (2001 - 2007) can pop off the lense.
  • scscarsscscars Posts: 92
    My 2002 230 K is having an unusual problem. In the morning, and especially when its cold, the passenger compartment receives gasoline fumes. :P My wife has taken this car to the Mercedes dealer where we bought it. They found nothing wrong with the fuel tank filter canister and they replaced the mass airflow sensor, which was not a cheap repair. We also changed where we purchase gas, thinking that maybe the quality of the fuel was an issue, but it isn't. We've apparently not found the cause and neither has our dealer's repair service, which has been very good over the years. :confuse: Does anyone have any ideas or similar experience? Thanks in advance.
  • vivid1vivid1 Posts: 24
    That is strange. How long has this been like this? One thing you could do is take out the back seat and look at the fuel pump housing. Its not hard to take out the back seat at all. It basically pops off. Just make sure everything is tight and looks normal.You will be able to really smell gas with the seat out if that is the issue. To see how to do this, search for "W203 removing back seat" in a search engine that rymes with foogle. The first hit will show you how to do it. (This board does not like for people to link to other sites) Hope this helps.
  • patpat Posts: 10,421
    You can put up a link to another site for the purpose of providing helpful information. What you can't do is say something like "go to for everything you need instead of here". ;)
  • huntzingerhuntzinger Posts: 356
    Looks like I have the W203...but didn't feel brave enough to risk popping it off and have the wife yell at me :-)

    I did find something else quite odd in that it looks like my back seats won't properly flip down ... seems to have a new (third) plastic clip thing between the hinges under the knees that's in the wrong position or something. Have to wonder just what the shop did to the car the last time it was in (I had them searching for a possible loose ground on the radio antenna amplifier).

  • scscarsscscars Posts: 92

    Thanks for your advice. By looking at other sites including the one you recommended, I was able to develop a list of possible culprits for the gas smell that included the fuel pump housing (turned out OK), a leaky fuel injector (Thankfully, not a problem. That is a very expensive repair), and bad fuel rail seals (Close, but not quite it). The problem turned out to be a worn out fuel pressure regulator that leaked fumes due to deterioration in the unit brought on by cold weather.

    Apparently, this is a growing problem in W203 engines and older C-Class models (1997-01) according to the mechanic, so W203 and earlier C-Class owners, beware. Repair costs are reasonable for this problem on a W203--about $135. Parts costs for other MB engine types might be higher depending on engine type and age.
  • mark_wnymark_wny Posts: 69
    I visited a dealer in Northeast US to look at an '05 CPO 240 4matic w/ 25K miles. Was surprised when service mgr outlined "normal maintenance items" -

    oil service every 10k miles - cost $180 - $300
    new brake rotors every 20 - 24K miles - cost $1050
    new tires every 20 - 24K miles - cost $800

    Is this normal? :confuse:
  • vivid1vivid1 Posts: 24
    Oil Service every 10k is right. Mine was free until 50,000 miles with my dealer. Just an oilchange at my dealer is 80 bucks.

    New brake rotors every 24k is not right. I did 55k on my wifes 240 until I changed them. Dealer was charging about 800. I did it myself. took about 2 hours.

    New tires every 20k??? No way. I have 55k on my original tires. New tires for this car are about 450-550. You dont have to buy them from a dealer. Go to a tire store. I going to buy some very soon. These still have an ok amount of tread left.
  • mark_wnymark_wny Posts: 69
    thanks vivid for the info.
  • rzenrzen Posts: 2
    I have a 02 C230 which I just purchased. I released the front passenger seat and put the seatback forward to get ready for a rear passenger. The seat automatically moved forward, and when it did, the headrest(which was in the highest position) got wedged between the winsheild, and the top of the head liner in front of the visor. The seat controls on the passenger side are not working now, and I cannot figure out how to unwedge the seat. Can anyone tell me how to fix this issue?
  • j_rohasj_rohas Posts: 6
    Reading old posts could to determinate that I can't change my MBC230's oil myself.
    Looks like this car doen's have a crankcase cap to drain the oil, and I need a oil pump or vaccum to drain the oil out. It's that true? or someone knows if this engine has a crankcase cap and where is it located.
  • rowlandjrowlandj Posts: 254
    You do need an extractor to get the oil out. I use a Pela unit, but you can get these devices at any marine supply house as it's the typical method for changing oil on inboard engines.

    Don't forget the right size socket for removal of the oil canister cap. I believe it's 27MM.
  • Did you ever figure this out?
    My mother's c230 does this consistently, in various pitches, anytime the fan is on for the climate control. THANKS
  • syvettesyvette Posts: 2
    My wife received a dealer estimate to replace a leaking rear brake line in a 2000 C230 Sport. The dealer says the gas tank must be removed along with a bunch of other things that are in the way. The estimate is $3,700.00. Can this be true?
This discussion has been closed.