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Based off research I think it is the crank shaft position sensor only thing it could be
Wrong, wrong, wrong. Why do you act like this? How old are you really?
Could be a number of things, from a blown fuse to more complicated issues. Low pressure in the fuel rail could cause it, dirty/bad air flow sensor could cause it.
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Originally Posted by sunsprit
as LaBonte beat me to it ... that's bad research.
so many possibilities for the no-start condition that I won't even try to go into them here.
suffice to say that it could be an intermittent fault in either the fuel or ignition system components, sensors, computers, grounds, wiring, or connectors.
these cars were very susceptible to intermittent electrical/electronic faults that can be difficult to replicate and isolate. the needed repairs can range from very simple to requiring some expensive component replacement ... and it's why you want a competent diagnostician instead of a guesser. I've seen a lot of parts replaced on these cars at great expense that weren't the fault ...
Guessers drive me batty. I had a guy once, who told me that he just replaced parts until it would start working again . That was the last time I let him work on something.
Reading the codes would help. Failing that, it's fairly easy to tell if it might be *related* to the crank sensor- put a noid light on a spark plug. If it lights, then it's getting spark and the problem is *not* the crank sensor and one would look elsewhere for the problem.
If there is no spark, check the output from the crank sensor with a multimeter (analog is better than digital for this). If no output, check the input. If no input, then there could be a blown fuse. If the input is good, check the ground wire. If the ground and input are both good, but there is no output then the sensor is bad.
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M-B has a set of proprietary diagnostic codes which will not show up in a conventional Fed mandated menu of trouble codes related to emissions compliance. When the dealership (or a shop that is a subscriber to the M-B database) plugs in their scanner, it's not like the scan tool that you can buy at an auto parts store ... it's a much more sophisticated system that links the car to the M-B factory computer. In fact, when linked, the external computer scans all systems in the car and will update all computers to the latest software programming. For example, you may bring you car into a shop for a routine service, and the link may update anything and everything from the fuel injection profile to the ABS computer to the climate control computer on-board ... it's a comprehensive scan and update, not just a fault code download. This is a major factor in the cost of a shop servicing M-B cars today; the subscription cost is a rather daunting figure and has got to be recaptured by diagnostic fees.
Of course, some failures/faults can be located with more basic diagnostic skills and equipment. But jumping to conclusions that a given sensor is intermittently out of whack without measuring or 'scoping the signal, and trying to drive the sensor into a failure mode with heat or cold or vibration and seeing the result is a waste of money and time. You may have read somewhere that the crank position sensor is a common failure item for this problem, but the real issue is getting the signal to the computer; ie, it might be the sensor, it might be the connector(s), it might be a wire failure, etc. So you could replace the sensor and still have an intermittent no-start if the failure on this circuit had a different causation. This is on the order of replacing a catalytic converter because that's the fault code that showed up yet the causation could be a manifold vacuum leak, a failing injector, or maybe even a bad oxy sensor ....
A professional shop will want to know to some certainty that they have located a problem and fixed it rather than guessing and swapping out parts at your expense. If they stand behind their work and you return with the same problem after spending a lot of money on it, the shop is now working on their dime instead of yours ... and there's not much profit in doing this work over again and again and again as a parts swapper, even if the shop charges you for the replaced parts each time. I've seen a lot of 'benz's dumped for low cost or traded in because they had undiagnosed problems like this even after spending a lot of money to locate and fix it ... there's a reason why these cars retain so little value from their new prices once they are out of warranty. The simpler, sturdier cars of years ago which could be diagnosed with common skills and tools are far removed from the latest technology which is incorporated into this car's computerized systems.
It really wouldn't add that much extra expense to a vehicle to put in an LCD screen on the dash that would read out the code and a plain English translation of the fault that would give one an idea of what to look at.
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Originally Posted by CCc girl
well, since the OP has all the answers to his supposed questions we're wasting our time here. Moving on.
I think that this is not the first time he's done this.
^^^^^^if a fuse is blown, it's blown. The OP's problem is intermittent.^^^^^^^^^
unfortunately, not necessarily so.
I've encountered more than a few failed fuses in these cars that had a hairline crack in the fusible link portion of the fuse.
They would perform intermittently. Sometimes the current load would arc at the remaining portions of the link and make contact for awhile, fusing the link together somewhat. Some of these failures were temperature related, some were electrical load related, some were vibration related ... and some were specific combinations of all three failure modes. Worst case, we had one lady who could stamp her feet in her 300E when it wouldn't start in cold weather and it would then start up ....
I've had more problems with euro car fuse box materials weakening from heat and age than you can imagine. We "solved" a lot of problems in M-B cars through the years by removing fuses, cleaning the contact areas, and ... in the process ... discovering the weak/failed fuse socket connectors. This was especially a problem in the older benz's with the bullet type ceramic fuses, but the later models didn't improve on this failure area very much. I used to insist that my techs actually remove fuses to inspect them on these cars because a visual check, and even using a test light to verify the connection didn't always give real results for an intermittent problem. Can't tell you how many times a fuse checked "good" with a test light but fell apart in the fingers of a tech when it was pulled out of the socket.
Similarly, this series of 'benz has a grounding circuit problem, and I'd suggest that my techs take apart, clean, inspect, and renew as needed every ground connection in the car related to ignition and fuel systems. These faults can really throw off the computers, to the point of a no-start condition being a plausible failure mode.
If there is no spark, check the output from the crank sensor with a multimeter (analog is better than digital for this). If no output, check the input. If no input, then there could be a blown fuse. If the input is good, check the ground wire. If the ground and input are both good, but there is no output then the sensor is bad.
Bad form to be using an analogue multimeter around these computerized cars.
Best to use an o'scope to check for input and output on these circuits, and even better than my old Tech and HP scopes is to use a modern DSO, such as found in most high dollar car scanners these days ....
"It really wouldn't add that much extra expense to a vehicle to put in an LCD screen on the dash that would read out the code and a plain English translation of the fault that would give one an idea of what to look at."
except that it would cut into the dealership and manufacturer control of the mandated emissions compliance and the manufacturer's proprietary control circuits for other functions in the cars. The dealer network likes to make their boat and college fund payments from keeping the service information close to their vest, have been doing it for years, and are highly unlikely to allow this cash cow to roam anywhere except in their barns.
Complicating all of the electronics diagnostics in these cars is the 'benz started using LIN Serial Bus technology for the computerized systems to communicate in 2002. This was done as a cost savings measure over the previous CAN protocols.
So a discrete component diagnostics via a given wire for a specific function are no longer what these cars have in them; one wire can carry the computer communication data of many sensors. I'm not sure what is in this 2005 model, but the LIN protocol at the time could accomodate 8mb of data stream continuously. Bottom line is that all of you techs out there pushing all kinds of diagnostic routines based upon cars without this technology don't have any real ability to read what is going on in these late M-B's, hence the computer diagnostic link system via M-B to connect each car being diagnosed to NJ's computer center. Without that computer link, we in the aftermarket are essentially restricted now to some basic investigations and very crude diagnostics on these cars; we may hit upon the problem area and solve it, but it's gonna' happen in spite of best diagnostic efforts done in a general sense of good automotive practice rather than a real diagnosis.
In all candor, I think this will come back to bite M-B very badly as these cars age and problems of this nature show up where the aftermarket has been essentially priced out of being able to diagnose these cars. And it's not just performance issues, it's everything from the climate control, cruise control, communications and entertainment systems, window controls, seat controls, mirror controls ... everything electronic in these cars. Once the costs of keeping one of these on the road is out of sight due to M-B not supporting cars past a certain age point (10 years, maybe?) the aftermarket won't be able to keep them on the road, either. FWIW, I spent $18,000 for M-B service connectivity the last year I tried to work on the newer cars for these problems ... and I couldn't justify the expense. It was more cost effective for me to isolate and replicate problems and then bring a customer car to the dealer for diagnostics then to guess at what the computer problems were. I got badly bitten over ABS brakes on a bunch of cars when 'benz kept dicking around with the computer programming for the control units; had customer cars locking up brakes going down the road due to program issues which they weren't solving but releasing new updates every so often. I finally had to tell my customers to take the cars to the 'benz dealers themselves because there was no way that I could solve the problems as an independent repair shop like I could with the 'benz products through the 1990's decade.
OP, you are just seeing the tip of the iceberg of the problems that will present with this 2005 car of yours. Don't begin for a minute to think that this vehicle has any of the reliability and repairability that was built into the cars through the 1980's vintage which 'benz built it's laurels on. Take a look at the cars of the 1990's decade and you'll see where 'benz really shot themselves in the foot ... many of those cars are off the road where new owners expected to buy that proverbial million mile car, built like a tank and sturdy and durable, even if they weren't going to keep it that long.
I, and many of my customers, put milliions of miles on 'benz products from the 60's-70's-80's, and were happy with the driving. But these are not what 'benz is producing today. Absent a track record of durability and reliability from this marque with their newest cars, I cannot recommend one of them to my customers as I did years ago. They're simply not what you think they are anymore, and the technology isn't proven at all.
Yes but since my mom gave it to me 3 years ago this is the only problem have had usually Mercedes are one of the most reliable cars on the road that's why im wondering what's happening.
I've encountered more than a few failed fuses in these cars that had a hairline crack in the fusible link portion of the fuse.
They would perform intermittently. Sometimes the current load would arc at the remaining portions of the link and make contact for awhile, fusing the link together somewhat. Some of these failures were temperature related, some were electrical load related, some were vibration related ... and some were specific combinations of all three failure modes. Worst case, we had one lady who could stamp her feet in her 300E when it wouldn't start in cold weather and it would then start up ....
I've had more problems with euro car fuse box materials weakening from heat and age than you can imagine. We "solved" a lot of problems in M-B cars through the years by removing fuses, cleaning the contact areas, and ... in the process ... discovering the weak/failed fuse socket connectors. This was especially a problem in the older benz's with the bullet type ceramic fuses, but the later models didn't improve on this failure area very much. I used to insist that my techs actually remove fuses to inspect them on these cars because a visual check, and even using a test light to verify the connection didn't always give real results for an intermittent problem. Can't tell you how many times a fuse checked "good" with a test light but fell apart in the fingers of a tech when it was pulled out of the socket.
Similarly, this series of 'benz has a grounding circuit problem, and I'd suggest that my techs take apart, clean, inspect, and renew as needed every ground connection in the car related to ignition and fuel systems. These faults can really throw off the computers, to the point of a no-start condition being a plausible failure mode.
My experience with Mercedes Benz autos has been limited to brake work. I'm thinking a 2005 model uses a blade type fuse. I have never encountered an intermittent fuse failure in these (blade type) fuses but I'm sure anything is possible. If you have run across that specific issue in late model MB's I believe you and I'll have to keep that in the back of my mind should this problem present itself in the future. You learn something new everyday.
If it is the rear one, exchanging it with the working one and scrubbing it down real well with prop wash will many times solve the problem.
Be careful when you jest about "PROP WASH" There was actually a company years ago that made a product designed to wash down and degrease propellers. The name of the product was PROP WASH.
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. That was the last time I let him work on something.
