Rear Right ABS (speed) sensor short circuit [Resolved]

So all of a sudden my T6.1 converted van has developed an ABS fault, the rear right speed sensor shows as short circuit. I have taken it to VW but as its converted they don't want to touch it as they suspect the converters have drilled through a cable loom somewhere. What I would like to know is, does anyone know the cable routing of the abs sensors from the back of the van to the front and where they entre the front cab of the van so i can have a look around. I have had the wheel well liner out and looked around there and behind the rear light all looks good. I need to find a good disconnect point to do some wiring checks as the sensor loom is hard wired in at the rear of the van. The sensor has been replaced with not effect, there are loads of faults related to the sensor and using odb11 the sensor reports no speed when driving.
 
more info here ( T6 ) :






cables run:

ABS unit>coupler under seat base>up B-pillar>allong passenger side roof edge>down C-pillar



************************************************************************

FYI - (yellow colour plug)

(Green) wire is T17f /9 - G46 Rear left speed sensor (do not connect to this)
(black) wire is T17f /10 - G46 Rear left speed sensor (do not connect to this)
T17f /2 - ABS - (do not connect to this)
T17f /3 - ABS - (do not connect to this)

T17f /8 - F11 Rear right door contact switch - (do not connect to this)
T17f /4 - F10 Rear right door contact switch - (do not connect to this)

T17 /11 - (white) G34 Front left brake pad wear sender - (do not connect to this)

T17 /12 - MX4 Right tail light - (do not connect to this)


1620041642074.png

1620041656736.png1620041663240.png





and T6.1 here:




J981 ESP unit
T10au connector purple
T17ab connector brown
G44/G46 speed sensor
 
Can you clear the fault? If you then start the van stationary and the fault occurs and you’ve fitted a new sensor then does sound like a wiring issue, on a t6 not sure on a 6.1 the loom runs up the osr corner across the back of the roof to the nsr top corner and then to the front down the b pillar to under passanger seat, but behind osr trim there is also an earth point
 
If you can’t clear with a new sensor fitted does confirm wiring issue

You would be looking for it to say implausible signal if it was sensor/ reluctor
 
have you taken the screws out and retested?

did the issue start when you moved that bracket?

you will have to remove the B-Pillar trim and have a look at the loom running up to see if its been damaged.
 
this guy shows a T5 with the trim removed.

the loom looks to be on the otherside.

maybe its been moved on the T6/T6.1?

you will need to check.


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It did start after I moved the bracket removing screws has no effect on errors. I have taken all the trim off and where I have drilled is a boxed off section you cannot see into. Now I know the cables come down I feel a bit happier as I cannot see any cables going into that area. I'm going to boroscope inside tomorrow at work.
 
from memory the loom runs this way . . .

well at least for the rear light clusters and the rear PDC sensors. (red route)

im not 100% sure on the rear wheel speed sensors and tank electrics? (possible second route in green)

but defiantly run from the connectors under the seat base.

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edit:

top view

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..
 
Last edited:
look for damage on these two wires

Rear Right speed sensor - G44

brown wire and a black wire

from sensor to - TSKVL -Coupling point in left seat box


+++

and T6.1 here:

https://www.t6forum.com/downloads/abs-wiring-diagram.185/



J981 ESP unit
T10au connector purple
T17ab connector brown
G44/G46 speed sensor

to test i would.

disconnect the speed sensor.

disconnect the loom connection point in seat base.

bell out each core (Black/brown) for a sort to each other or to ground.

that will tell you if the short issue is between the sensor and seat connection and on which wire/or both.

you could use the ohm reading to get a rough idea of the length cable vs short.
then either trace the loom back inch by inch looking for the damaged cable.

or just cut out the old damaged wire, and replace with a new wire. (test this first with a loose run wire tapped into the circuit. - see if faults clear)

then run new cable in as a perm fitting. (cut back into loom at D-pillar location inside van)
 
Just found this also which helps. The converts are going to take the van back so see if they can find the fault just want to make sure its nothing i have done first.

vw camper wiring harness.JPG
 
If your loom is like my T6 there is a plug & socket connection in the loom along the roof line at the rear almost at the top of the D post. That didn't exist on a T5. Maybe if yours is the same it gives you another test/isolation point.
 
Boroscoped the area where I moved the bracket and no cables so I will leave it to the converters to find and fix the fault. Will update when I have one.
 
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