2004 XC70 AWD not working

[boostedxc]

I have a controller from a 04 v70

You think I need one?

I have no idea, could definitely be a range of things. Never experienced this problem before on my personal XC.

[XC70newtoME]

Curious how you made out with the Dorman pump and BBA Reman? I’m debating whether to spend 1k for Xemodex DEM and pump or $500 for BBA reman DEM Dorman pump. I’m leaning toward Xemodex because I haven’t seen any bad reviews for them and BBA (US facility anyway) seems to have at least 50% bad reviews.

[shiloh51933]

The AOC AWD system is not active without engine running. The hydraulic pump is not turned on until the engine running data bit is broadcast on network. If you do the same things with eng running and you do not have considerable effort to turn the wheel then there is a problem. The AOC will have a low clutch apply pressure when you are doing the test so you could turn the wheel if you apply enough force to exceed clutch load.
You can also do a very quick trst to see if there is a DEM (awd controller) code(s) by having engine running and then hold the READ button on end of turn sig lever and then push the rear fog light button twice. Then the display in cluster will show checking and then likely "DTCs IN VEHICLE" Then pushing the READ button will scroll through the list showing "xxx CHECKING", "xxx READY", or 'XXX DTC SET". checking means it has no DTC but the diag sequence is incomplete, usually has to be driven for this to turn to READY. Ready is no dtc set. You can't see what the code is but if it has no DEM DTC then the temp/pressure sensor is not faulty. No dtc doesn't mean you are in the clear as the coupler sleeve between trans and the angle gear that drives rear driveshaft could be worn out and the spin by hand

I know this is kinda old but I'm back trying to solve this. I cant spin the rear driveshaft by hand at all.

[- Pete -]

With the ignition & engine off Haldex/DEM pump is not running.

If you cannot spin the driveshaft by hand that is a good sign - it verifies your angle gear & collar sleeve should be in working order, but it has nothing to do with verifying the functional status of the AOC/Haldex/DEM pump.

Yes - it is normal to be able to spin either of the rear wheels, even if only 1 of them is off the ground. You can have all 3 of the other wheels on the ground & still be able to spin whichever rear wheel is off the ground because the DEM pump is not running since the ignition & engine are off - that is normal. Think of the AOC (active on demand coupler) as just that - an electronic coupler that locks the driveshaft to the rear differential which then transmits the power to the rear wheels, but only when the DEM pump is powered.

Haldex 3 will allow a maximum of 15 degrees front wheel spin before engaging the rear drive. 15* is not very much. You should be able to get on gravel or ice & goose it to see if the rears are getting power.

Did you ever re-try the rudimentary DTC check in the instrument cluster? It should say DEM ready if it is functioning.

These pumps sort of flake out intermittently towards the end of their lifespan so you may have AWD only on occasion. In my experience when the dying pump kicks on sporadically it is usually felt as an abrupt jolt, akin to what it would feel like to drive over a garden hose while accelerating. I see a lot of talk about them only being good for 10-12 years, regardless of mileage. I'm not really sure how that can be true, but it's what's written. My first DEM pump went out slowly, finally giving up completely around 275k miles & almost 16 years of age.

With the car running you should be able to get your head next to the pump for an audible test. They make plenty of noise when healthy.

Edit: there is a slim chance your AOC fluid has never been changed and/or the filter has never been replaced. These can both contribute to loss of your rear drive, but I think your situation is more likely a dead pump.

[shiloh51933]

With the ignition & engine off Haldex/DEM pump is not running.

If you cannot spin the driveshaft by hand that is a good sign - it verifies your angle gear & collar sleeve should be in working order, but it has nothing to do with verifying the functional status of the AOC/Haldex/DEM pump.

Yes - it is normal to be able to spin either of the rear wheels, even if only 1 of them is off the ground. You can have all 3 of the other wheels on the ground & still be able to spin whichever rear wheel is off the ground because the DEM pump is not running since the ignition & engine are off - that is normal. Think of the AOC (active on demand coupler) as just that - an electronic coupler that locks the driveshaft to the rear differential which then transmits the power to the rear wheels, but only when the DEM pump is powered.

Haldex 3 will allow a maximum of 15 degrees front wheel spin before engaging the rear drive. 15* is not very much. You should be able to get on gravel or ice & goose it to see if the rears are getting power.

Did you ever re-try the rudimentary DTC check in the instrument cluster? It should say DEM ready if it is functioning.

These pumps sort of flake out intermittently towards the end of their lifespan so you may have AWD only on occasion. In my experience when the dying pump kicks on sporadically it is usually felt as an abrupt jolt, akin to what it would feel like to drive over a garden hose while accelerating. I see a lot of talk about them only being good for 10-12 years, regardless of mileage. I'm not really sure how that can be true, but it's what's written. My first DEM pump went out slowly, finally giving up completely around 275k miles & almost 16 years of age.

With the car running you should be able to get your head next to the pump for an audible test. They make plenty of noise when healthy.

Edit: there is a slim chance your AOC fluid has never been changed and/or the filter has never been replaced. These can both contribute to loss of your rear drive, but I think your situation is more likely a dead pump.

Thank you for replying Pete. I checked for DEM DTC, I believe it said checking originally and same thing when I checked recently. I've never changed the AOC oil/filter, I should have but never did. I've owned for over 100k and I've every other oil(ATF numerous times, angle gear oil twice, coolant, ect..) I always meant too but there was something I checked following Xemodex suggestions that led me to believe it was the pressure sensor but I don't remember what. Anyway you think the actual pump is shot? It does have 255k, so it sounds right.

[- Pete -]

At those miles & never having changed the AOC oil nor filter, I’d say the pump is the most likely culprit, but you will have to do your own investigative work to verify.

Do you have ViDA?
Or can you get to somebody who does?

My first one I troubleshot without ViDA & replaced without an outline of the procedure.

[shiloh51933]

At those miles & never having changed the AOC oil nor filter, I’d say the pump is the most likely culprit, but you will have to do your own investigative work to verify.

Do you have ViDA?
Or can you get to somebody who does?

My first one I troubleshot without ViDA & replaced without an outline of the procedure.

Right, most likely the culprit.

Yes I do actually have VIDA/DICE, I purchased recently the VIDA program with the DICE DLC connector. I have issues with the installation of VIDA, I'm using a brand new Lenova laptop with Windows 10 but something isn't right so I'm not able to utilize that right now.

[- Pete -]

I'd encourage you to have a new filter/finned cover & a liter of fresh AOC oil on hand. If you end up needing to replace the pump you will want to do the filter at the same time.

These guys made a pretty great video.



EDIT: I personally would not take the "Haldex" labeled cover off unless you have absolutely ruled out the pump is not the problem.

ViDA should be able to tell you a pretty good story about what's going on. I, after only 7 months of trying different things/laptops, finally fumbled my way into a functional ViDA/DiCE that's able to communicate with vehicles. I can barely get around a keyboard, so it was a miracle to finally have it working. Still very new to it but there is such an incredible wealth of knowledge to be had in it. RickHaleParker can answer just about any question you have on the topic in the ViDA forum.

[XC70Rider]

During every oil change I give the Haldex pump a test by applying 12V to the connector. It's the smaller of the 2 external connectors on the DEM. You can apply the 12V jumper cables in either direction. If the pump isn't burnt yet then you'll hear it turn on. An Indy mechanic said reversing the pump can give it a few more miles if it's on the edge.

Already done a haldex fluid and filter change. My P2 only has 135k miles so I'm holding off on replacing the pump. I'll either rebuild the Haldex pump or install a new OEM pump when it hits the grave.

[shiloh51933]

I'd encourage you to have a new filter/finned cover & a liter of fresh AOC oil on hand. If you end up needing to replace the pump you will want to do the filter at the same time.

These guys made a pretty great video.



EDIT: I personally would not take the "Haldex" labeled cover off unless you have absolutely ruled out the pump is not the problem.

ViDA should be able to tell you a pretty good story about what's going on. I, after only 7 months of trying different things/laptops, finally fumbled my way into a functional ViDA/DiCE that's able to communicate with vehicles. I can barely get around a keyboard, so it was a miracle to finally have it working. Still very new to it but there is such an incredible wealth of knowledge to be had in it. RickHaleParker can answer just about any question you have on the topic in the ViDA forum.

I tried installing VIDA a few times unsuccessfully. I took a look at the DTC check on my instrument cluster, it says "DEM NOT CHECKED". I did the DTC check after driving her for a while, so it looks like it's not getting a reading.