Terminate The Limp Mode Mercedes ! - PeachParts Mercedes-Benz Forum

sdanville · #1 07-19-2007, 11:35 AM

My stomach is turning again. One day before leaving on vacation and pulling my small boat, the Check engine light starts flashing and the ^&*(*&^%$@#$#@ Mercedes goes to limp mode. Ive replaced the plugs 4 times 3 MASS, CPS, Checked Wires, Cleaned injectors, -

I wouldnt care so much if I had a little miss and could drive it safe to my destination, but the stinking Limp Mode makes it run like crap, holds up traffic, fouls the spark plugs and is dangerous.

I have even put the ML320 in neutral on the fly and restarted it to get it out of limp mode to keep up with traffic. ( restarts take it off limp mode until the computer decides to reinstall Limp mode ).

This is my 1st and last Mercedes. For safety reasons the "Limp Mode" should be eliminated.

supradupe · #2 07-19-2007, 11:38 AM

did you ever replace the low range position motor? that's usually the cause for the limp home mode.

sdanville · #3 07-19-2007, 11:49 AM

No,
Didnt even know i had one.

supradupe · #4 07-19-2007, 12:50 PM

yes, your situation happened to me before, it was fixed after dealer replaced the low range position motor. been fine ever since. it is a easy diy, I wish I knew this back then. the part itself was $100 or $150, I couldn't remember.

sdanville · #5 07-19-2007, 12:53 PM

But did your ML go into the limp mode because of Miss fires ?

I have PO300 multi miss fires show up on the scanner.

jobaa · #6 07-19-2007, 01:19 PM

i had the 300 code come up on mine too. turns there were 2 other codes as well 302 & 304 indicating a misfire on #2 and #4 cylinders. i replaced those 2 coils and it seemed to fix the problem.

RMorano · #7 09-06-2007, 08:31 PM

We need the limp mode, we also need to band together and create more class action suits for all of the other issues. WE must force MB to fix their crap via federal mandated recalls....

BAVBMW · #8 09-06-2007, 10:43 PM

The "we" I referred to meant the American public, or at least the vast majority of it who drives. If you read the last of my previous post, you'll see where I alluded to the series of events that begin when people complain, and end with legislation.

The public was growing tired of increasingly complicated automotive systems, all the special tools required to work on them, the manufacturers were keeping information to themselves, and people were complaining. So the government stepped in. They mandated sharing of information (at least for several "critical" systems), and mandated the adoption of standardized trouble codes and nomenclature. They also standardized diagnostic connectors and network protocols allowing one piece of diagnostic equipment to access multiple vehicle lines with very little trouble. This allowed other manufacturers to create cheap "one-size-fits-all" scan tools that allow just about anyone to read out a trouble code.

The trouble is, they never quite got around to mandating that everyone had a solid knowledge of the basic principles of automotive operation. People started scanning vehicles and swapping parts left and right, with some success, and even more "less than spectactular results". And then someone (Al Gore?) invented the internet, and message boards were quick to follow. Now everyone was sharing their lack of knowledge (or lack thereof, as the case may be...) worldwide at incredible speed! Experts were born and destroyed daily, tales of someone's brother-in-law fixing the check engine light in his Jeep by replacing the oxygen sensor spread like wildfire! Everyone had to get in on it, what harm could come of convincing some stranger who you'd never met, who's car you'd never seen, that he needed to buy expensive parts? It's not your money, right? You'll never see this guy. And so it went...

Mind you, I'm not talking solely of do-it-youselfers. There were/are problems across the board. Well meaning friends and family, neighbors, autoparts stores, even (dare i say it?) less than reputable automotive repair shops, even dealerships (I dared). Some steps have been taken to remedy this, some by consumers, who slowly grow wise to the shops that don't know what they're doing, and some by authorities that remind autoparts stores that they are not licensed automotive repair facilities and cannot offer advice as to what parts need replaced (many stores continue to do so, but the state of CA is slowly working to stop them).

But enough of all that. Your concern was with limp mode. "Limp mode" came about as part of OBDII, most specifically, the part where the vehicle's computer had to be able to shutdown cylinders that were misfiring, both to protect the enviroment and the vehicle/occupants. A misfiring cylinder will send raw fuel into the exhaust, which besides being an enviromental problem, can/will cause damage to the catalytic convertor. In particular, it can cause the cat to overheat, reaching temps that can cause the vehicle to actually ignite (this is considered bad for the occupants, as well as the vehicle). Sometimes a disintegrating cat wil spit out chunks or red/white hot material which can start wildfires by the side of the road.

Many manufacturers learned however, that the driving public, who was largely raised with the 70's and 80's "smog-dogs", didn't particularly notice and/or care when a cylinder or two was shut off. Today's cars can run so well with a cylinder or two missing that many never notice. In order to get the consumer to actually stop driving the vehicle and get it fixed, more drastic measure had to be taken. Hence "limp mode". Reduced output, but enough functionality to allow the customer to be able to get safely off of the road, and quite often, to the repair facilty. Sure, there's the odd customer or two who get's his panties all in a ruffle because he can't use his malfunctioning vehicle to, say, tow a boat on vacation, but overall the system works fairly well.

That's about it for limp mode. I'm sorry you haven't been able to find a competent repair shop. Unfortunately, I don't personally know anyone in your area to recommend. I'm not going to tell you that the dealer is the way to go, I see just as many hacks there as anywhere, possibly more, as here in the "real world" we have to survive by actually fixing cars. As a technician in an independent shop, if I don't fix the car, the customer doesn't pay. We haven't any manufacturers warranty to subsidize our shop.

As far as what a guy like me does? Well, I can't say I've never made a mistake, but I've always done everything in my power to make it right in the end. Every vehicle gets a thorough test drive, and the only time they leave with the problem still there is when the customer wants to take them. Bear in mind also that many times people will opt to only fix the immediate problem, by say, replacing the sparkplug wires for only cylinder number 3. It stands to reason, that barring any outside influence (rubbing, rodent snackage...) that if that cylinder's wires are bad, the rest can't be far behind. I understand that it's a lot of money to replace all 12 wires at once, but it sure beats coming back and doing two every two months for two years, especially when you factor in diagnostic time each visit.

I think the guys you're used to dealing with are perhaps a bit more lazy, a bit less skilled, and maybe just a bit unqualified. Some of us are professionals and take pride in our work. But most of you don't care. If a shop offers cheap oil changes and brakes, and maybe throws in a car wash, you're sold. For the record, I'm every bit as disappointed in the lack of skilled technicians in my profession as I am in the lack of people who care enough to seek out those skilled techs.

Oh, and in regards to the rest of your post, the premature failings of EGRs, CPS's, MASS's, those are Mercedes issues. They built the vehicle, I just fix them. Except for the window switch. That was me. All me baby, I f*&ked that one up good just for you.

Any more questions?

MV

ILUVMILS · #9 09-09-2007, 04:21 PM

Quote:

Originally Posted by BAVBMW

We haven't any manufacturers warranty to subsidize our shop.

I totally agree with everything in this post with the exception of this quote. Contrary to popular belief, factory warranty isn't the Golden Goose it used to be.

BAVBMW · #10 09-09-2007, 08:21 PM

I didn't mean to imply that the factory was just easy money, I know those days are over. But from my time at a dealer, they were way more willing to try throwing a part at a problem than a customer ever was. Warranty seemed happier to "try" something and send the car on it's way than I as a tech ever have been.

Customers want to bring the car in and go home with it fixed, which is an entirely reasonable expectation. I hated, as a service advisor, having to tell a customer that they should mark their survey that we had fixed the vehicle in one visit when we diagnosed it one day, ordered a part, and had them come back at a later date for the actual repair. True, the actual repair was done in one visit, but no one with any bit of sense would count it that way. Correct diagnoses is part of the process, and if that's done on one day, and the repair on another, that's not one visit. I suppose we could have just held the vehicle for a week while we waited on the part, but for a window switch, that seems rediculous. Even if it does make the survey come out in your favor...

I felt that at the dealer, vehicles exhibiting syptoms of a known pattern failure were often just assumed to have that actual problem, the standard parts were installed, and it was sent on it's way. As an example:

While it is true that many a misfire is caused by a faulty plug wire, not all of them are, and when you replace wires and send the car out, without checking every aspect of it, you leave yourself wide open for the comeback when it turns out to have a bad injector. Sure, better than 9 out of 10 are wires, but for that tenth one... man, can you blame the customer for feeling like you messed up?

Warranty was happy to go the first route, and worry about it later if the problem persisted, paying customers, not so much... And a creative warranty clerk at the dealership could make sure that the dealer got paid for every visit. That doesn't work when it's one on one with the customer.

Don't get me wrong, I think the problem lies mainly with the factory and their warranty standards. They don't want to pay for the time to correctly diagnose, so the techs don't want to do it. I can't blame them. Very few people I know want to work for free. Even less whose work consists of cuts, scrapes, burns, and bruises (sore backs and necks aside...). The real problem lies in the fact that this approach leaves very few techs who have the desire to correctly diagnose vehicles, and fewer still it seems who have the skills. It's hard to justify a day spent looking over wiring diagrams to trace out one circut, for an hour's pay, when the guy in the next stall has booked 15 hours just swapping out the parts the factory tells him to. Then when the vehicle comes in where "the normal thing" isn't the problem, there isn't anyone around who knows what to do. Somehow, that factory who was so full of advise before, dissappears right quick. It does fantastic things for a dealer's image, that's for sure.

Perhaps the biggest problem? I don't know how to fix the current situation. Dealers and factories don't want to pay to train expert techs, when 9 out of 10 times it's not needed. Customers don't want to pay for the time it does take to diagnose a problem. Employers don't want to pay for skilled techs, until that problem car rolls through the door, usually for the second or third time. Without pay, how does one keep skilled techs working?

Myself, I'm a sucker for good old fashioned work. I love the challenge of diagnosing problems, and I love that at the end of the day, I can say "Look what I did". I could easily make more money delivering boxes, or working packing boxes at a number of local plants. But I couldn't live with myself knowing all I did was fill a box with potato chips, and tomorrow, I'd fill more boxes. Besides, I'll be spending next week upgrading the brakes, swapping the differential, and adding over 100 horses to a M3... That's much better than any plant job I can imagine...

MV

john_Ten · #11 09-13-2007, 01:45 AM

BAVBMW
you (and al gore) are obviosly passionate about your craft. I get it and appreciate your advice. I would appreciate your professional and technical advice please - although i'm an avid diy'er. I let my local redwood city mb dealship service my 2000ml430 with 80k miles. after a recent $2100 B-service, plus fuel filter/lines and MAS 2 weeks ago, the truck needed a tow back to the dealership for a $600 Egr (according to mb) the next day. The egr lasted a day, check engine light along with significant stuttering and hesitation followed. now with GREAT apprehension, I'm bringing the truck back to the mb dealership (they know I'm really frurstrated and broke). the service manager says he thinks I may need a cps however he has not
diagnosed the problem. my cheap scanner is giving me p0170,po173 and po0300's. appreciate your advice regarding:

1) how do I deal with the mb dealership and what recoarse do I have.?what I mean by that is, the car was fully functional with no problems until i brought it to mb. at what point (if ever) does the dealship take accountability for what I believe is misdiagnosis that lead to excessive costs leaving me with an unsafe and unreliable car?

2) did replacing the fuel filter and line upgrade throw off the balance of the other systems - dumb question i know but I'm wondering why the fuel delivery upgrade was required and why I was required to pay for it if it was in fact a design flaw...

john_Ten · #12 09-13-2007, 01:48 AM

BAVBMW
you (and al gore) are obviosly passionate about your craft. I get it and I would appreciate your professional and technical advice please - although i'm an avid diy'er. I let my local redwood city mb dealship service my 2000ml430 with 80k miles. after a recent $2100 B-service, plus fuel filter/lines and MAS 2 weeks ago, the truck needed a tow back to the dealership for a $600 Egr (according to mb) the next day. The egr lasted a day, check engine light along with significant stuttering and hesitation followed. now with GREAT apprehension, I'm bringing the truck back to the mb dealership (they know I'm really frurstrated and broke). the service manager says he thinks I may need a cps however he has not
diagnosed the problem. my cheap scanner is giving me p0170,po173 and po0300's. appreciate your advice regarding:

1) how do I deal with the mb dealership and what recoarse do I have.?what I mean by that is, the car was fully functional with no problems until i brought it to mb. at what point (if ever) does the dealship take accountability for what I believe is misdiagnosis that lead to excessive costs leaving me with an unsafe and unreliable car?

2) did replacing the fuel filter and line upgrade throw off the balance of the other systems - dumb question i know but I'm wondering why the fuel delivery upgrade was required and why I was required to pay for it if it - was it in fact a design flaw that should be an mb cost?

john_Ten · #13 09-17-2007, 11:17 PM

steve
my wife wanted it done by mb, she felt safer. I got completely hosed - learned my lesson. today mb wanted another $3k to replace the fuel pump, plugs and wires, leaky valve cover and leaky power steering - I almost threw up at the thought of paying them a total of $5.5k over the past 4 weeks. how do they get away with it. I think George Bush said it well or at lease tried to - you can fool me once, shame on you - you can fool me twice shame on me...

I replaced the cps on sunday afternoon with the help of my sons skinny arms. what's involved replacing the fuel pump? thanks

sdanville · #14 09-18-2007, 08:42 AM

I am sure there are some posts here with directions. I may have even posted my experience.
and i did it about 3 years ago.
It was a breeze.
I had to remove the back seat, no big deal, then there is a paint can lid that pops off and exposes the pump. the new pumps and or filters have quick release fittings if I recall. The old ones hose clamps I think.
It was easy and I think I paid about $200 online for the pump and filter.

I feel your pain with the repair bills. You could buy lots of nice things for $5000 in repairs. Like Buy an 8 year old Accord that needs nothing but oil and tires and brake pads.

I'm thinking used GM next. Honda's dont depreciate enough and I dont want to spend $30,000.

strelnik · #15 03-09-2020, 02:32 PM

Quote:

Originally Posted by john_Ten

steve
my wife wanted it done by mb, she felt safer.

Don't believe that. The prior owner of my 123 took his car for a valve adjustment job on the OM616.912 and after 400.00, the car was barely driveable.

That's how I ended up buying it. The PO wanted no more hassle at 79.

I paid the former owner what he wanted for the car, redid the valves, then thanked the service manager of the local MB dealership for helping me get the car.

He was not amused. Especially since I went in a suit and did it in front of one of the dealership owners.

Hey, if you don't like it, shave my head and send me to Vietnam.