pnorrgren

Hi,
first post. be gentle. (I have searched the forum but not foud any answers, so if I missed them, apologies)

I am using my AUTEL MaxiDAS DS808 diagnostic tool and it shows me that there is no reading from the front right wheel. reads 0 when moving the car whereas the other three shows movement.
I have swapped RHS and LHS sensors over but the error remains on the RHS.
ohm meeter on the loom connector shows one wire is hard ground and the other infinite open. there is no cross connection.
Did a small intrusive opening of the wiring some 40cm upstream from the connector to check the wiring at the connector end, but ohm meeter shows no break in cable.

before doing anything more, I thougth I would ask the experienced Benz population
- have you seen something similar?
- are there known points where the wiring loom can get damaged?
- I assume the hard ground on one of the cables could be correct as it is a magnetic sensor so it would need one side earth and the other side the is the signal side? is this a correct assumption or should I start chasing the cable looking for some damage?

greatful for any pointers.
thank you
all the best
Per Norrgren

Rudeney

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I am not sure that one lead should go to ground. Looking at the wiring diagram, both leads (blue/gray and read/gray) go directly into the ESP control moduel (pins 32 and 33, respectively). I might start by checking continuity from the module's wiring to the connector in the fender.

pnorrgren

Thank you Rudeney,
that is very helpful.
I shall start working my way back to the fender connector from the ECU and see if I can find the short.

all the best
Per Norrgren

Rudeney

In case you need the full ESP wiring diagram:

http://benzbits.com/w209/ESPwiringDiagram.pdf

Rudeney

Per, I just posted the full wiring diagram int he thread. Hope that helps!

pnorrgren

Thanks Rodney, that is great. very helpful. will check during the day. all the best. Per Norrgren

pnorrgren

Thanks Rodney for the wiring diagram. was very helpful.
Could work out that it was the cable and not the sensor or any connector or ESP unit.
Total break in the signal cable somewhere in the engine compartment.
And what did I find?
somehow deep down in front of the fuse box, some serious damage to the cable loom.
one cable cut in two places and another cable was half cut and some minor damage to a few more cables.
Suspision is that someone has left a tool of some sort in the engine compartment and then closed the lid. easily done.
but, I have owned the car for two years and no one but me have lifted that lid, so must be an old damage that finally went bad.

added some pictures.

now the nasty "Go to garage imidiately" message has been replaced by a more friendly "ESP and BAS not available, consult owner's manual" message, what ever that can mean.
onwards and upwards, the search goes on.
(at somepoint I have to change the aircon compressor, and might need some thoughts about that when the day comes.)
all the best
Per Norrgren

The second signal cable for the FR ABS sensor is also cut, but only 1/2 way through.

Well deep down in fron of the fusebox. what ever did that?

ABS sensor signal cable cut in two places, had to add 4cm of cable to bridge the gap. solder and cover, job done. :-)

pnorrgren

Problem finally fixed.
just needed to run the diagnostic and reset the error codes and now the ESP and BAS are happy and working
thanks again.
Per Norrgren

Rudeney

The "ESP unavailable" message usually just means that you need to reset the steering angle sensor. Glad you got it working! Those cut wires are something of a mystery. I would suggest rodents, but I see no signs of chewing. Hopefully it was not some sort of malicious activity by an enemy!

pnorrgren

thanks. yes very strange. but the little cable was damaged in two places as if a tube or socket or something had been smashed down on the loom.
I will never know for sure, but all good now.
again, thanks for your help.
all the best.
Per Norrgren