bas/esp again

[dave thomas]

hi i have a slk 230 on a 03 plate , i had the bas/esp on i changed the brake s/w, i bought for eurocar parts,no problem for 1k miles now its back on ?what is the problem with this fault on the merc,s i have been told that this switch also provides a 12v supply to a module? does the switch make and brake on both poles ?if it only makes/brake on the brake light side,can i brigde the other side of the poles to see if this will cure the problem? or should i buy a mercedes s/w,regards dave

 

[television]

It does sound as though the new one has failed.

When they fail, the CAN bus signal gets killed, and the car cannot find the BAS or ESP components. You could pull of the connector and the message may go out, if it does, then the switch

 

[Alex Crow]

..........When they fail, the CAN bus signal gets killed, and the car cannot find the BAS or ESP components.....

can you elaborate on this statement please malcolm, i am never sure what you mean by this.

 

[television]

can you elaborate on this statement please malcolm, i am never sure what you mean by this.

CAN communication with traction system disturbed, no stop lamp CAN signal, no wheel speed CAN signal.

Will that do

 

[Alex Crow]

wheel speed signals are still transmitted over the CAN when the switch fails.

it is not a can component, but is wired into the relevent braking/traction/stability control system (and also eg light switch module, ESM etc). sure enough with a faulty switch you will get various knock on symptoms, but can communication itself remains unaffected.

 

[drdre78]

hi best bet is read fault code from esp/bas with star.

 

[television]

wheel speed signals are still transmitted over the CAN when the switch fails.

it is not a can component, but is wired into the relevent braking/traction/stability control system (and also eg light switch module, ESM etc). sure enough with a faulty switch you will get various knock on symptoms, but can communication itself remains unaffected.

You are wrong and the CAN communication is affected, scope one up and you will see it.

Also do tell MB that they have worded it all wrong as that was copied word for word from WIS.

I thought that you understood CAN buses better Alex, you should know that when SAM's go down they lose track of what is on the car, and you do not replace all the things shown as faulty that come on in the dash.

With a shorted, corrupted or open circuit CAN Items on that can often will not work, eventually when the main activity has died down some things may be found, but that is not the situation here

 

[Alex Crow]

malcolm, do point me to the WIS document you refer to, please.

what is this??
"I thought that you understood CAN buses better Alex (ouch), you should know that when SAM's go down they lose track of what is on the car, and you do not replace all the things shown as faulty that come on in the dash"

stop changing the subject please malcolm, we are not talking about sam units 'forgetting' what modules are installed, this is stop lamp switch talk here.

and thanks for the dig too, nice one.

 

[television]

malcolm, do point me to the WIS document you refer to, please.

what is this??
"I thought that you understood CAN buses better Alex (ouch), you should know that when SAM's go down they lose track of what is on the car, and you do not replace all the things shown as faulty that come on in the dash"

stop changing the subject please malcolm, we are not talking about sam units 'forgetting' what modules are installed, this is stop lamp switch talk here.

and thanks for the dig too, nice one.

Thats OK things can go two ways, and I get the digs. I can read things into your post when I have answered something.

I did say the this was not the problem here if you had cared to read down to the bottom of my post, it was another way of how lost CAN signals can throw up faults

Yes you have much more MB experience than me, sadly you cannot answer every post, but I do when ever possible like on this one where I have answered successfully for years on the same faults.

I will put up the document number later, and please do not pull a face as it is for a different model. these faults are no longer shown is WIS as MB know that we all know these faults

it even affects mine, but not listed as such, only by the fault code as on all the rest

 

[television]

On AF43.05-P-2000A it says the control module does not acknowledge the CAN message stop lamp switch.

On AF42.31-P.8000A it says Fault code C1025 "CAN communication with traction system control unit disturbed, no stop lamp switch CAN signal, No wheel speed CAN signal"


Its a shame Alex that things are like this between us, you are the skilled brainy one working on the cars, where as I am just a mere mortal who tries and does his best to help here, sure I may not always know exactly where things are, or I make a mistake, but that is not the end of the world.

Just for reference the stop lamp switch can cause the selector lever to lock up as well when faulty, due to it not getting any CAN signal from this switch.

Its all been discussed on here years ago.

 

[Alex Crow]

When they fail, the CAN bus signal gets killed, and the car cannot find the BAS or ESP components....

come on malcolm, when you are wrong you are wrong.
we all make mistakes, all of us.






malcom,

i have every respect for your contributions here, and no-one would argue with my assertion that you are the single most helpful poster and contributer to this forum and its members.
your obvious knowledge and understanding of all things, especially those electrical and electronic, is clear for all to see.

i am perpelxed that you feel you have found personal digs directed toward you in any of my previous posts.
i always try to keep my meanings transparent - there is a risk of misunderstandings in internet text communication.

my aim here is always to add to the knowledge base here - sometimes that does mean clarifying points and so forth.
if i feel that some information or advice given is in any way misleading or incorrect i consider adding a bit myself.
i can assure you that i am far more likely not to contradict posters in these cases, i am not really one for causing unecessary conflict.

 

[television]

OK I said

Originally Posted by television View Post
When they fail, the CAN bus signal gets killed, and the car cannot find the BAS or ESP components....


Does it matter at all how the CAN signals are lost, killed, disturbed or whatever for this brake lamp switch.

There are very few that know how the CAN works.

Maybe I am just over reacting to it all through things at home.

I would just love to disappear of the face of the globe today.

 

[Richard Elliot]

As far as I am concerned you both provide a load of helpful and free advice to us mortals, personally I have no idea what a CAN bus or a SAM module is but don't disappear off the face of the globe since we all know that electronic problems are so hard to diagnose and cure.

 

[television]

Alex I am disappointed that you could not say that I was not wrong.

In post 5 you said these are not CAN related components, you were wrong, they are.

You also say that the wheel speed sensors do not come into this when in fact they do, that is why on some cars the gear shift locks up in park when the CAN gets corrupted.

So at the end of the day it is still faulty CAN signals causing these problems.

You asked me to put up the WIS document, so I put up 2 different ones showing that what I said was correct, yet you choose not to acknowledge them.

If I am wrong I would rather know about it, and I will always say sorry, for wrong information is useless, it does hurt when I am told that I am wrong when when I was not.

 

[Alex Crow]

Alex I am disappointed that you could not say that I was not wrong.
if it were true, i would say it.

In post 5 you said these are not CAN related components, you were wrong, they are.
No............... i said this - "it is not a can component, but is wired into the relevent braking/traction/stability control system".
a brake pedal switch is not a can component, but its values are interpreted by the relevent module and shared on the can bus. there are many other similar components on the car which are not wired into the can bus, but are 'read' by ECUs that are - a throttle position sensor is a good example, its values are also shared with other modules and can give knock on problems in other systems.

You also say that the wheel speed sensors do not come into this when in fact they do, that is why on some cars the gear shift locks up in park when the CAN gets corrupted.
No........... i said this - "wheel speed signals are still transmitted over the CAN when the switch fails"
think about it, the speedometer still works when the pedal switch fails

So at the end of the day it is still faulty CAN signals causing these problems.
errr no, its faulty brake pedal switches causing these problems.

You asked me to put up the WIS document, so I put up 2 different ones showing that what I said was correct, yet you choose not to acknowledge them.
sadly i do not have access to the documents at the moment. if you wish to quote whole passages i will of course read them. i doubt it will support your asssertion that "When they fail, the CAN bus signal gets killed, and the car cannot find the BAS or ESP components"

If I am wrong I would rather know about it, (I tried!) and I will always say sorry, for wrong information is useless, it does hurt when I am told that I am wrong when when I was not.

...........................................

 

[television]

Alex you may have blinded others in your reply but not me.

Quite simply put, It matters not how it is wired or indeed if there is any direct connection to the CAN bus or not in this case the CAN signals become corrupted because of the Switch.

I will not go through it all again, if the switch can cause the selector lever to lock up but leave the speedometer alone, that is quite easy to explain in that the CAN signal received can be intelligible for the speedo but not the selector lever, the can signal only has to be missing 1 x 0 for any malfunction to occur

Also as the same cars like the 210 for instance can have a faulty brake switch that can lock the selector lever on one hand and bring up the BAS fault on the other, but never both at the same time does show that the CAN is corrupted.


You must write to MB and tell them that WIS and all of their training programs are all wrong, I told you I posted word for word direct on two counts, but you have not had time to check them, how sad.


I doubt that I will have time tomorrow to follow anything up so you can say what you like. I am very disappointed in your response and replies,,, you do think you are a god beyond MB and most of us all, but at least I know how CAN buses work