When you get your new computerized car, some steps should be taken in order to test the electronic systems. Those cars are not only cars any longer, they are also a computer - or more correctly a central computer controlling 10-20 sub-computers.

Use a couple of days to enjoy your new car, and when you feel ready and when you have the day off, drive to your dealer and park outside. With engine running begin to stress test the computer system by exercising all buttons, a few to start with, then more and more faster and faster also simultaneously. Bring a kid along and ask the kid to do the same, usually kids and outsiders are the best to discover software bugs in computer systems with user interface. Monitor closely what happens when. If the computers halts or funny stuff begins to happen, you now know that the computer system has its limitations, and what you can do and what you shouldn't do. Any computer system has its limitations. Now go to your dealer and show him the error on the screen and ask him why, perhaps your system needs a software update.

At BenzWorld ( http://forums.mbnz.org/forums/forums...osts=10&fid=57 ) I red atazmans post regarding his "first problem" with the new W221. Could be because they both tried to adjust the seats simultaneously - perhaps the computer cant handle simultaneous requests ? Seat setting etc. are most likely saved in the main computer, so when you want to recall a setting your seat will contact the central computer and ask for it to set the seat for you - if two seats does this simultaneously I imagine such thing may happen. Or the central computer thinks the seat is in one position, but the actual seat position is in an other - then a censor problem - need to take the seat apart and adjust the sensors - if they exist ?

Check for how many days you can leave the car in the garage without the need of jump starting the car. If necessary - make the dealer exchange the battery for one with extra capacity. The electrical system consumes vast amount of power in sleep mode. You could consider to install a permanent jump start kit in your garage and get a mechanics to instruct you in how to use it correctly !

And now to the rain test. The worst enemy to computers is water and humidity ( well except for handymen and car mechanics fumbling on the electronics without taking proper precautions for handling electrostatic discharge ). Chose a day with weather forecast predicting heavy rain all day. Bring a bunch of your favorite CD´s with you and drive around the block of your dealer for a couple of hours or more. Exercise all windows up and down as well as all buttons connected to anything electrical too. Now you know if your car is water proof and if the electronics well protected.

Precautions to consider:

Avoid to drive the car in heavy rain, use the back-up car if possible, or at least avoid to open the windows in rainy weather.

Make sure that the car mechanics is professional trained in electrical computer systems before you let him fumble with controller boards in the car - I imagine that most damages are done while you are in for a simple problem, and inexperienced mechanics destroys driver boards while fumbling around in the system ! Thats propably why your car stays for weeks in the shop with no news.

Locate an experienced expert in your particular cars computer system before you buy your car - and stick with him.

Learn by serching the net all the possible electrical problems with your particular car model ( + airmatic problems ), and know their symptoms, appropiate precautions and actions to be taken.

Get the dealer to show you how to RESET the whole thing - just as you do on your PC when it stalls. The car should have a RESET button - right ?


You could aslo consider to perform the above computer stress test in the show room before you buy the car, or/and insist to test drive the car in heavy rain

Remember ( now the positive part ):

Luxury cars are produced in a low volume compared to other consumer electronics, on top of this car computing systems are extremely complex compared to other consumer electronics and placed in a highly stressed environment, I can only think of the Space Shuttle and offshore platforms as more harsh environment for computer electronics.

If you know the computer systems limitations and what you can do, and what you shouldn't do, and take a few precautions - I think you can adjust your life and enjoy your luxury computerized car.


After all its a toy and a luxury item.


Now to the real bad news:

Since it has been demonstrated many times by many independent users, that windows and seat positions are not always as the central computer thinks it is, imagine what happens when this very intelligent car detects a upcoming colission. It will do its job - close all windows, tighten all seatbelts, set all seats to vertical position .............

 

Should we drive our car 5 mph into a light pole to test the bumpers?

 

welcome to the forum MBdriver1.

am about to eat my dinner but found your post a bit challenging.

i agree half of what you have stated in there, but some thing i have to enlighten.

they can handle because they each got separate door control module which keeps the memory and initializations.
the only time that the left door control module communicates with the right door control module is when you adjust the mirror and fold/unfold them.

i don't get this one. all cars got a pressurized shower test before passing the assembly line for final test. opening the window will let the water enter and ruin the accessories.
they are designed to function normally on controlled environment... the reason why the air-conditioning system occupies almost all what's under that dashboard.

the quisent current consumption during sleep mode is 0.08 amperes. under normal battery condition, this cannot discharge your battery for 3 months. the battery control module monitors the load and shutdown anything that is found faulty. the second extra battery is only for starting the car whenever the main battery really goes flat (the battery is self discharging at the rate of 1% everyday...maximum 2% for less than 1 year old battery).

this is not going to happen if the seats were not programmed or initilized. it's the same as the windows. the control unit must know it's start and end stop position before it can function accordingly.

 

Which raises the real question:

How can you test something when you don't know how it works?

 

Thanks - a little fast entry perhaps.

Seats and colission:
The message atazmans got from the dealer was a computer problem. I think only a few systems programmers - those who made the operating system and board drivers realy knows which communication and exchange of data is going on in the CAN network. However if the problem was in the local seat computer, even worse. Then nobody knows the correct position of the seats in the entire system. Imagine what happends when the central computer sends a colission alert to the local seat computer.....

Water in doors:
So no cars on the market should have problems with water in the doors ? Materials change on wear and use, also rubber parts on car doors.

Jump start kit.
This post was ment to be a general post for all computerized cars. Read elswere about the new E-class problems on this subject. Let W221 owners do their own home test. I suppose they did put in an extra battery for a reason.

 

An even better question - how can you buy a 100.000 $ car without knowing how it works or with out testing it firmly ?
Most people propably checks more firmly how the TV or DVD-player works before buying - than before buying their new computerized car !

 

i haven't read the link yet, but later i will. i think atazmans got some wrong understanding or info from others.
the PRE-SAFE and function for the seat won't work /activate if it was not initialized (which means the fore / aft position, up /down must be stored and the position remembered via hall sensor). it means that if there is no stored position in the memory, it is dis-abled and therefore no danger of being pinched. however, the emergency tensioning retractor of the buckle and the belt (3 stages...depending on impact force) still works, and so are the airbags.

this i agree. weathering will change the material properties of those seals. but it takes time. some cars of more than 10 years old still got good sealing trim on them.

yes we have many complaints of battery drain cause by some faulty control modules. they are not normal current consumers. the faulty CAN send wake up signal to them continously which increase the sleep mode current to 3 amperes (more or less).

this is a nice topic and gives us more better understanding on the electronic side of the car. they keep on upgrading them day to day and hard to catch-up.

i really need to learn more.

 

Well, I used to test software early in my career (I'm retired now). My employer hired Booz-Allen-Hamilton (BAH) and Ross Perot's outfit to come in and see how we did our job and to make recommendations on how to improve it. Their final reports stated they had nothing to offer in terms of improving our work. In fact, BAH hinted that they were the ones who learned something. Ross Perot's boys weren't as gracious and remained mum, though I believe they also pick up some tips. So, to get to my point, I probably look at testing a little different than you do, and the guy who wrote the testing procedure you quoted. I won't bore you with how a test should be conducted, since we don't have access to the most important tool needed to do it right, the customer's technical requirements.

If it makes you warm and fuzzy to push all the buttons in your $100K car all at the same time, then I say do it. Anything that makes us happier nowadays is a good thing. I don't call that a test, however. It's just pushing a bunch of buttons all at the same time.

I agree with the latest point you've made. I too believe it's important for a person to learn how to use all of the features of their car. That's not testing, though. I think it's important no matter how much you spend on it.

 

I wasn't aware of this topic till one of my friends told me to be aware of electrical problems in the newer cars. That was when I told him that I was to buy a S500 W220.

I own a company developing and manufacturing small industrial credit card sized embedded computers based on the embedded Intel 386EX processor. So was surprised to learn - mainly from this excellent site - that newer luxury cars are full of computers - and that practically all newer computerized cars independently of manufacturer have problems.

Providing black-box industrial solutions where long term reliability is critical, I find it very dairy to control vital functions in a car by one or several computers. I question the scenario that car mechanics not educated in electronics is servicing these cars. We should be buying shares in the car repair and service companies. They will be fortuned the coming years.

More than 1.000$ for a controller board with a cost price below 30$ is hilarious. Thinking of that most controller boards replaced most probably are damaged by the shop it self, in their uneducated and inexperienced search for the reason of a simple problem in a complex system.

We are at a stage where the customer have no chance to know or prove what is wrong with his car. A mechanical failure is usually easy to detect, mechanics normally gives you a warning before it fails, and have a natural life till it fails. Lifetime of electronics is all statistical. An electronic component or system may fail in 10 seconds or in 10 years, nobody knows till it fails. There is no way to inspect the electronics system for upcoming failures, it may fail while you are driving 220km/h on the German highway - now that's scary.

 

very true.
it's murphy's law again.
anything can go wrong because it's bound to go wrong.

on some certain degree they are acceptable.
this is the reason why the word "warranty" was born. means we can tolerate it if breaks down after 1 or 3 years.

parts are not made to last forever (i mention it before). they have their functional limit although the material can last for a million years.

so it doesn't matter if you get W140 or W220. the single control module for EGAS or throttle on W140 S600 will cost you $2400. in W220, it is 3 times less.

it's a matter of choice. people got different preferences... comfort, power, functionality or price.

as for me, anything with 4 wheels and engine under the hood is good enough. just to take my family out on weekend and urgent trips.