ESP and wheel alignment

abittenbinder

Doktor A (864-623-9110)
A group member e-mailed asking for more info on this subject. ESP
monitors steering wheel position and rate of change of steering wheel
position and wheel speeds(in addition to Yaw rate and lateral
acceleration). If a steering wheel deviation from straight ahead(even
minute changes) fails to correlate with the change that should occur
in a right vs. left wheel speed sensor signal(remember the right and
left wheels scribe differing radii in a turn-hence differing speeds)-
if that info doesn't match the programmed maps- then the ESP control
unit labels it "implausible" and your applicable dash MILs light up.
Merely aligning the front toe-in and carefully aligning steering
wheel, by sight, is NOT enough! The steering wheel position sensor
needs to be recalibrated using the DRBIII and its software. The DRBIII
program walks the tech through a calibration sequence.
If you own a pre-ESP model Sprinter then wheel alignments are simple and straightforward checking and adjustment of toe-in. Remember, Camber and Caster are not adjustable-If these are out of spec- something is deformed. Doktor Andy
 

NorthLink

NorthLink
Quick question: I was driving across North Dakota today with 30 mile an hour sideways wind gusts. The van really got rocked by one, and then I notice that my ESP light and ABS light (the wheel with the up/down arrow; I think that is the ABS system light) are on. Of course, there was some serious sideways movement, and I had just either pulled in front of a semi truck or out from under an overpass, so the front and rear were probably not pushed equally.
I had a patient in back, so I just continued on (I learned my lesson the hard way: never shut it off with a patient on a stretcher in the back) to Dickinson ND. Here I am, finally able to turn it off, and sure enough, it starts without the warning lights coming on. I haven't driven it much so I don't know if they'll come on when I get back on the freeway. Won't know til tomorrow am.

So I'm hoping: can a sporadic twist/sideways jolt just trigger the lights, and then the system is fine? Or will I need to have the front aligned?

I suppose the answer depends on whether the lights come on again?

Thanks for putting up with sometimes not the greatest questions.

Geo
 

jdcaples

Not Suitable w/220v Gen
<snip>
If you own a pre-ESP model Sprinter then wheel alignments are simple and straightforward checking and adjustment of toe-in. Remember, Camber and Caster are not adjustable-If these are out of spec- something is deformed. Doktor Andy
<snip>
Even though it is in the T1N section I presume this revived thread also applies to the NCV3 ESP design?
<snip>
I can't speak to details beyond this: There is documentation (right or wrong, I can't say) supporting the idea that for NAFTA NCV3s, both camber and toe-in are adjustable.

https://sprinter-source.com/forums/showthread.php?t=1309

-Jon
 

sailquik

Well-known member
Hi George,
The ASR/ESP lights will nearly always go out after a complete shut down/ restart sequence.
If you have had an incident (like yours with the crosswind) that caused enough "plausability" (or lack there of) to
trip the sensors, the light (s) will stay on until you shut it off and allow the ECM and ASR/ESP modules to reset.
If it comes back on as soon as you restart, then you have some kind of issue with the wheel sensors or brake system.
What happened when you got the big gust of crosswind, was that the ASR (traction control or the steering plausability)was
"tripped" by different wheel speeds or the yaw angle change rate, and the automatic correction (instantaneous application
of one or more of the brakes) kicked in and straightened you out. The lights are there to tell you that this "safety system"
actually deployed to help you stay in your lane and on the road.
In this case, since you were fighting the crosswind, I think the systems worked in your favor and exactly as they were
designed to work. They kept you on the road, in your lane, and prevented a spinout or other much more serious loss of
control of the direction your Sprinter was traveling.
My guess is that you "over corrected" a bit when the gust hit you and the steering sensors suggested that you had too much
steering angle for the speed you were going, so they system applied the brake on the outside rear wheel (from the directon you
turned the steering wheel) to straighten you out.
Roger


Quick question: I was driving across North Dakota today with 30 mile an hour sideways wind gusts. The van really got rocked by one, and then I notice that my ESP light and ABS light (the wheel with the up/down arrow; I think that is the ABS system light) are on. Of course, there was some serious sideways movement, and I had just either pulled in front of a semi truck or out from under an overpass, so the front and rear were probably not pushed equally.
I had a patient in back, so I just continued on (I learned my lesson the hard way: never shut it off with a patient on a stretcher in the back) to Dickinson ND. Here I am, finally able to turn it off, and sure enough, it starts without the warning lights coming on. I haven't driven it much so I don't know if they'll come on when I get back on the freeway. Won't know til tomorrow am.

So I'm hoping: can a sporadic twist/sideways jolt just trigger the lights, and then the system is fine? Or will I need to have the front aligned?

I suppose the answer depends on whether the lights come on again?

Thanks for putting up with sometimes not the greatest questions.

Geo
 

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