DEM BCM faults

[The Landshark]

Hi all,
Afer looking for nearly a year i finally found myself a nice xc70 with a couple of problems,
Vida shows DEM-0006 and BCM-0095,
It'll be fun getting to the bottom of this, i'm assuming the electrical connections to the dem and the haldex pump are the first thing to look at,
i also have a failed parking sensor and a knock out of the front suspension on bumps(shock top mounts perhaps),
apart from that it seems to be a very well minded car, the interior is spotless,
there's 263,000 kms on the clock and the engine seems perfect,
I also want to change the gearbox oil, diff oil, bevel gear oil and aoc oil, engine is a D5 diesel and its got a 6 speed manual gearbox.
Does anyone know the specification for the above oils or is it main dealer?
Thanks for any input/advice.

[The Landshark]

Just an update, i pulled the dem this evening, can resistance is showing 62.1 ohms so i assume thats ok,
voltage output to the aoc pump is 3.45 open circuit, couldn't get the meter probes on the pins to measure closed circuit voltage,
now the question is is the dem not putting enough voltage to the pump or is the pump drawing too much current and the dem is shutting it down?,
Just a couple of further queries, what voltage does the pump run on or is it pulsed dc?
can i wire 12v directly to the pump and what's the maximum current drain i should see on a good pump?
again thanks in advance for any info

[Thames]

Hi !

Please take a look at this page :

http://xemodex.ca/ca/xemodex-technical-resources/


It contains *all* detailed steps to diagnose your DEM issues. Real good info there.

[The Landshark]

Hi !

Please take a look at this page :

http://xemodex.ca/ca/xemodex-technical-resources/


It contains *all* detailed steps to diagnose your DEM issues. Real good info there.

Thanks, very useful link that!

[The Landshark]

OK,
got the pump stripped out this morning, brushes worn to nothing, anyone got a source for new brushes or is it a replacement motor/pump?

[The Landshark]

Managed to repair the pump, temporary fix, i filed down some brushes off an old cordless drill and fitted them under the originals, pump now works,
i have however ordered a new one from haldexparts.com, the temporary repair is just that, temporary,
the old one has done 263,000kms so irs not so bad,
I drained the oil and removed the filter too. The oil looked fairly good as did the filter but i'd say it's the first time it was touched.
Ill get it back together next weekend if the parts arrive.
Thanks again for the link to the troubleshooting flowchart, hopefully the new pump will sort the issues.

[Antherzoll]

I'd like to see pictures of this repair if possible. If you searched hard enough I'm sure you could find the correct brushes. Being that a new pump is like $500 it may be useful to some.

[The Landshark]

I'd like to see pictures of this repair if possible. If you searched hard enough I'm sure you could find the correct brushes. Being that a new pump is like $500 it may be useful to some.

Ill take the old motor apart next weekend and post a few shots of it.

[tapanitja]

Ill take the old motor apart next weekend and post a few shots of it.

Hi,
had few years ago to replace the pump due to same DTCs you got. Since everything has been ok so far.
I have the old pump still an I'm most interested about fixing it for the next change as it seems to be a weak point of this design.

br Tapsa

[The Landshark]

Does anyone know the torque figure for the aoc driven flange retaining nut?
i cant find it on vida,
thanks

Edit: Found it eventually, 150nm for future reference

[The Landshark]

I somehow managed to order the wrong pump so the old one went back in today, all dem codes now cleared and the awd works fine. took about 600ml of oil to fill,
i ran the pump for 5 minutes and then topped up the aoc.
i took some pictures of the old pump assembly so ill post em when i get a chance to load em up off the phone.

[Antherzoll]

So the old, repaired pump went in. I'd be interested to see how long it runs for. Looking forward to the pics!

[The Landshark]

So the old, repaired pump went in. I'd be interested to see how long it runs for. Looking forward to the pics!


Ok as promised, here's the pump, i removed the small screw holding the motor cover in place, i also cut the wires but don't unless you have to.
It should be possible to do this with the wires intact.

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_210910.jpg

Remove the three screws on the intake plate and remove the screen

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211015.jpg

Remove the intake plate to reveal the pump itself

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211026.jpg

Next remove the three screws securing the pump to the motor body and separate the two

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211119.jpg

Prise out the tangs securing the backplate to the motor body

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211219.jpg

And remove the plate, there's a wavy washer between the plate and the bearing, take care it doesn't fly out.
i pressed the pump end shaft into its bearing to give me enough room to access the brushes.

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211311.jpg

Hook the brush retaining spring out of the way(again these can fly off into the furthest recesses of your workshop) and remove the brush, as you can see these were worn down all the way

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211432.jpg

Here's the scavenged brush filed to size

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_211450.jpg

Clean the commutator with a little emery paper and wipe clean.
Pop the new brush in the slot, put the old brush in after it and refit the spring.

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_212855.jpg

Test motor and reassemble

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_215205.jpg

rejoin the wires to the connector

http://i1146.photobucket.com/albums/o525/jimllbreakit/Mobile%20Uploads/2015-02/20150207_215235.jpg

Notes,
1. Mark the pump body, the motor body, the end cap and the brush plate, I didn't and had to make several attempts to get everything lined up so the wires line up with the case grommet.
2. I think this job can be done without cutting the wires. the hardest thing I had to do was getting the wires back out the grommet.
3. I replaced all o-rings when reassembly.
4. You will need a T8 torx bit to remove the cover screw and a T10 for the six pump screws.
5. Be careful with the intake screen, it is easily damaged.
6. I lubricated the pump and o-rings with a little aoc oil when assembling.

[Antherzoll]

Bookmarked.

Thank You!

[tapanitja]

Hi, thanks for an exellent presentation of fix!
I understood You put a piece of new brush between commutator and spring loaded old brush.
My question would be: the new brush part You made, was it originally a spare brush for
- starter motor, generator, cylar fan or which type of emotor to get the best suitable piece of carbon brush to work with.
br Tapsa

[The Landshark]

Hi, thanks for an exellent presentation of fix!
I understood You put a piece of new brush between commutator and spring loaded old brush.
My question would be: the new brush part You made, was it originally a spare brush for
- starter motor, generator, cylar fan or which type of emotor to get the best suitable piece of carbon brush to work with.
br Tapsa

The pieces of brush i used were scavenged from a broken cheap 18v cordless drill that was lying in a box in the corner of my workshop. they didn't have an integrated wire.
I would have replaced the brushes completely if they did, the brushes used in the haldex pump motor are small, less than 5mm x 5mm any they were less than 10mm long when new(i didn't measure them).
it took less than a minute to file them to size, the graphite used to make them is relatively soft and can easily be filed.
when the new, correct, pump arrives ill pull the repaired pump and source a better set of brushes, with the integrated wire, and solder them in place, if it helps you guys i will post pics of this job when it's done.
I think i have a set of spare brushes for an angle grinder somewhere that might work but will need a lot of filing to get them to the right size.

Edit: I would think that something like this would suit. http://www.ebay.ie/itm/Dyson-YDK-Motor-Carbon-Brushes-DC04-DC07-DC14-Etc-2Pk-New-/310678899524?pt=LH_DefaultDomain_205&hash=item4855e7cb44

[tapanitja]

Hi, the proposed Dyson YDK brushes are for 240VAC/1600W category ones. The Haldex Pump operates on 12V DC, current pulses, ave current could be 5A ie. 60W DC.
The generators (AC) and starters are in 12V 1000W and around 100A designs, brushes should have different features.
The cabin fan motors might be close to haldex ones and also DC operated so spare brushes for those could be a good choise?
br Tapsa


The pieces of brush i used were scavenged from a broken cheap 18v cordless drill that was lying in a box in the corner of my workshop. they didn't have an integrated wire.
I would have replaced the brushes completely if they did, the brushes used in the haldex pump motor are small, less than 5mm x 5mm any they were less than 10mm long when new(i didn't measure them).
it took less than a minute to file them to size, the graphite used to make them is relatively soft and can easily be filed.
when the new, correct, pump arrives ill pull the repaired pump and source a better set of brushes, with the integrated wire, and solder them in place, if it helps you guys i will post pics of this job when it's done.
I think i have a set of spare brushes for an angle grinder somewhere that might work but will need a lot of filing to get them to the right size.

Edit: I would think that something like this would suit. http://www.ebay.ie/itm/Dyson-YDK-Motor-Carbon-Brushes-DC04-DC07-DC14-Etc-2Pk-New-/310678899524?pt=LH_DefaultDomain_205&hash=item4855e7cb44

[Antherzoll]

Hi, the proposed Dyson YDK brushes are for 240VAC/1600W category ones. The Haldex Pump operates on 12V DC, current pulses, ave current could be 5A ie. 60W DC.
The generators (AC) and starters are in 12V 1000W and around 100A designs, brushes should have different features.
The cabin fan motors might be close to haldex ones and also DC operated so spare brushes for those could be a good choise?
br Tapsa

Make sure you get brushes for low voltage applications as they will have less of a voltage drop then high voltage brushes. I think cordless drill brushes are fine.

[The Landshark]

Hi, the proposed Dyson YDK brushes are for 240VAC/1600W category ones. The Haldex Pump operates on 12V DC, current pulses, ave current could be 5A ie. 60W DC.
The generators (AC) and starters are in 12V 1000W and around 100A designs, brushes should have different features.
The cabin fan motors might be close to haldex ones and also DC operated so spare brushes for those could be a good choise?
br Tapsa


Make sure you get brushes for low voltage applications as they will have less of a voltage drop then high voltage brushes. I think cordless drill brushes are fine.

Thanks Lads, you learn something new every day, ill try to source some off a cabin air fan motor (there should be a few around here),
I honestly just thought they were a lump of graphite and once the shape was right they'd work.
I'm not very well up on motor design, though if i can figure out why something doesn't work i can usually effect a repair.
I hate to hand over €700 to the dealer when its only a few euros worth of brushes that's at fault, at least the internet gives a bit more choice when it comes to sourcing parts.
The Haldex unit is still working fine anyway.
While I'm posting i'd like to mention www.haldexparts.com. i ordered the pump online on Saturday and it arrived Tuesday morning(i know it was wrong but that's my fault)
Correct replacement arrived today, the cost for the correct pump was £209(uk pounds) so a substantial saving on the dealer price, might be of help to someone someday.

[The Landshark]

Quick question, got an anti skid temporarily off message today, dtc code dem-0007 faulty pressure sensor.
Only have one recorded occurrence of this, is it possible that the pump got some air and suffered a pressure drop? or have I a faulty sensor.

[JRL]

Pressure sensor is not the DEM itself. These can get dirty, clogged up and fail.
This is THE cheapest AWD repair, under $300, closer to $200

[The Landshark]

Pressure sensor is not the DEM itself. These can get dirty, clogged up and fail.
This is THE cheapest AWD repair, under $300, closer to $200

Ill leave it for a while and see does the fault re-occur, vida lists two part numbers 30759668 and 30651694. the first is an 80bar unit and the second is 40bar, i assume its the 80bar i need, cn is 228188

[Antherzoll]

I've had a similar fault present after a fun day of drifting, AWD has been fine since. Reset and forget!

[tapanitja]

Quick question, got an anti skid temporarily off message today, dtc code dem-0007 faulty pressure sensor.
Only have one recorded occurrence of this, is it possible that the pump got some air and suffered a pressure drop? or have I a faulty sensor.
Hi, my aoc problems started with sporadic bcm0095/dem0006 dtcs and later dem0007 got repaired with new pump. The tmp/pressure sensor is still the original one.
br tapsa

[The Landshark]

DEM-0007 occurred 27 out of 38 cycles, new pressure sensor i think, while i'm under there ill pull the pump and swap in the new one.
I got a proper set of brushes off a 24vdc motor so ill fit them to the old pump, handy to have a spare.
By the way, has anyone ever had to do a set of clutch plates on one of these, if so is it a difficult job?