ESP, BAS, ABS lights on (E320 CDI)

[E Class Man]

Can anyone help with this one. I purchased my E320 CDI Estate (Registered March 2000) a couple of months ago and it is a great car. However it has been blighted by one really difficult persistent snag.
After driving 8 to 10 miles the ESP, BAS and ABS lights come on and when I reach destination and switch off, the fault has cleared next time I switch the ignition on again.
This fault never appears on a short trip, only after 8 to 10 miles on the motorway.
I took the car to Mercedes Benz Redhill and their computer showed ESP fault (Code 1140) with steering angle sensor failure. The sensor was duly changed and of course 8 to 10 miles later, on the lights come again. I took the car back to the dealer and they ran the test again and said the steering angle sensor was showing failed so they would replace it again. It seems unlikely that this unit has failed again and at exactly the same 8 - 10 miles! I suspect that is not the answer.
I pointed out that since I've had the car, the steering wheel set up is wrong in that the cross piece of the wheel is at 2 o'clock/ 8 o'clock instead of 3 o'clock/ 9 o'clock when driving in a straight line. This implies the track rod end settings are incorrect even though the wheel alignment may be correct. They (the dealer) said the steering geometry might be why I get this fault light problem.

So my questions are:
1/ Has anyone else suffered this problem and what is the solution. I have seen other examples described in these pages though not quite as I describe above with the 8 to 10 mile time delay in it appearing.
2/ Will the steering geometry set up affect the steering angle sensor and produce this problem? (I don't want to throw more good money after bad!)
3/ I have seen in other posts here that there is a wiring mod to fix a problem somewhat like this. Is this wiring mod appropriate to my car, will it fix this snag and can I fit it myself?

Any help anyone can give would be much appreciated as I don't have confidence that the local dealer can resolve it other than by a rather hit and miss approach which is very expensive for me!!

Regards,
E Class Man

 

[wagger]

most usual cause for this problem is brake light switch. I have had experience of this fault as have most other mb owners. hope this helps

regards
wagger

 

[E Class Man]

Thanks Wagger,
Why doesn't the brake light switch show on the computer diagnostic? Also the car had a new brake light switch at the last service (just before I got the car) perhaps this has failed again.
I'd also like to know what the connection is between the brake light switch and these systems.
Any ideas anyone.

E Class man

 

[markp]

The BAS & ESP systems pick up signals from the brake light switch but this would not cause a problem with the ABS as well
Generally the diagnostic equipment (assuming you are using a main dealer) is accurate in its diagnosis unless there is a wiring fault to the steering angle sensor
A geometry check is very unlikely to resolve this problem even if the steering is out of align. I would raise the question as to how it is the steering wheel is not in the correct position.

 

[Andy]

Hi

I would get the steering wheel set up right first. We have had a similar problem where the light is put on due to the steering angle sensor is feeding incorect information due to the steering wheel being out.

If the brake light switch was at fault. Then it would show up in the Star Diagnosis machine either as a stored or current fault. Although the dealer can go through the actuations on the system & check the switch operation.

Also I would get them (if the steering wheel problem does not resolve the original fault). Check the readings of the ABS sensor out put. Although I would be guessing. Usually the Star Diag machine is reliable. Or what is needed is a bit of lateral thinking & find out what could cause the lateral sensor fault to come on. Which then leads back to the steering wheel.

By the sounds of it. Too get the steering wheel correct. Then a four wheel alignment will need to be carried out & the track set.

Hope this helps.

Give you something to say to them anyway.


Regards

Andy @ www.mercedesservicing.com

 

[piestore]

bas esp

Hi

I would agree with Andy if the steering is off centre bas esp is seeing a turn angle of perhaps 10 degrees yet all the wheel speed signals are equal therefore both can't be right it brings up a fault code.

Read the actaul value of the steering angle sensor when the wheels are in the straight ahead position this should be no more than +or- 5 degrees the ML is even more sensative no more than +or- 2.5 degrees

Note :-

Even if you have a full geo check this doesn't include setting the steering angle sensor

 

[E Class Man]

Thanks for your responses. I will get the steering set up correctly and get the steering angle sensor output meassured in the straight ahead position as you suggest and see if that cures the problem.
Regards
ECM

 

[mrfirepro]

same problem

E Class Man,

I have the same problem on a 1998 E430 the lights come on after 8 - 10 miles and my steering wheel is as described above at 2 to 8. I have been told that I need some bushes replaced. But when put on the diagnostic machine it comes up with a senso fault on the brake servo which has been replaced to no avail.

I know this does not help you but if you manage to sort it would you let me know my email is paul.darke@ntlworld.com

Regards

Paul

 

[Phynyxun]

In my CLK 55 I had this problem, BAS, ESP and ABS failure...


3 MALFUNCTIONS it comes up with on the display thing...

The thing to do is, ignore it...

 

[dieselman]

Until you need either BAS, ESP, or ABS.

I wonder what your insurance company would say?

 

[Andy]

Especially as the fault codes would still be there in the event of an accident

Regards

Andy

 

[mrfirepro]

BAS, ESP, or ABS

It is nice to know that you guys were all right..........(no supirse there then)

2 days ago I put my car into Quick fit to set the tracking properly and realign the steering wheel. Since I have had this done the various indicators no longer come on.

And what a bargain only 20 quid..........

This happy story does have a sort of funny ending though..........after having MB look at the problem over a week ago and read the codes, they have decided in there..............infinite wisdom, that i need a new sensor on the servo and how lucky I was that it was only going to cost me £293 plus fitting and VAT :evil: . I didn't have the heart to tell them that it was sorted.
:lol:


I hope the problem remains sorted..........

Paul

 

[DaveS]

Re: BAS, ESP, or ABS

..........after having MB look at the problem over a week ago and read the codes, they have decided in there..............infinite wisdom, that i need a new sensor on the servo and how lucky I was that it was only going to cost me £293 plus fitting and VAT :evil: . I didn't have the heart to tell them that it was sorted.

:lol:


I think you should tell your the Director at your garage. I've found, since becoming an MB owner, that the garages treat you like their personal cash dispenser.

 

[E Class Man]

Sorry I am so late posting this. I have not been on the forum for a while.

I have resolved this problem now.

The steering wheel has been reset to 9 - 3 o'clock postion with the wheels straight ahead. The lights now no longer come on.
Apparently the steering wheel sensor tells the ESP how much lock is on the car and it needs to know this in order to calculate the correct relative wheel speeds when going round a corner (outer wheel goes further than inner of course). The chances are greater of wheel spin when lock is greater so ESP backs off the power to prevent wheel spin by varying amounts dependent on steering lock.
To do this it needs to know what the correct wheel speeds should be for any given lock. When the steering angle sensor is straight ahead all wheel speeds should be identical. However if the steering wheel angle is incorrect (a steering angle other than straight ahead is detected by the system) but the wheel speeds are identical then it knows something must be wrong. This brings on the ESP light and that brings on the BAS and ABS lights.
This only shows itself after 8 or 10 miles of straight driving as it takes this long for it to average out the wheel speeds and see the problem. If you stick to country roads with ever changing wheel speeds and steering angles then the problem never surfaces.
Hence it is important that the steering wheel says straight ahead when the wheels are straight ahead.
Shame I had to buy a new steering sensor before I found this out. Why don't the dealers know this stuff??

Hope this helps.
E class man

 

[OlafMaxwell]

That bit about steering wheel being 9/3 o'clock is elementary stuff. Dealer should know that. The first thing you do when you check a car for alignment is check the steering wheel and the wheel alignment, tracking etc. Dealer should not have sold you the car with the steering wheel not aligned. He should have remedied that before selling. Worth checking the car has not been in an accident.