I picked up an 06 XC70 with about 150k on it this week for super cheap. It is in nearly perfect condition inside and out, but had a few issues that the previous owners just didn't want to deal with so they bought a new Volvo instead.

Most of the issues are relatively minor and I can deal with them (they gave me a copy of the list of issues the dealer told them about), but I discovered a big one that I don't think they were aware of: the AWD does not work.

This car has the Haldex system. Today I pulled the prop shaft, filter, pump, DEM, and pressure sensor. The oil didn't look too terrible, but the filter looks like it should definitely be replaced. My understanding is the filter often plugs up and starves the pump of oil, so it in turn fails, but sometimes it is just the pressure sensor.

I am torn on what to try replacing beyond the filter. Can I feed 12v to the pump to confirm if it functions?

Any suggestions? Am I on the right track?

 

You are on the right track. You can phone a Volvo dealer (i use Tasca parts.com) for discounted parts and fluid for the Haldex and you may find good used pumps at a junkyard (VW used them too, Hollander guide will cross ref them). IIRC there is a thread on here for checking the pump but its old, you will have to dig hard for it.

 

Great; thanks!

I put 12v to the pump (tapped it to the battery in my truck for a few seconds) and it definitely sounds like I imagine it should.

The filtration material in the filter I pulled is black (looks like it was white originally based on photos). So, I ordered a Haldex Filter and will get some new Haldex fluid, put it all back together, and see what happens. Here's hoping it was just a filter/fluid issue, or that it's a pressure sensor at worse. I really hope it's not the DEM.

 

While you are waiting for the fluid and filter you should shop for a pump. Heading it whirr may or may not mean its OK. By the way where'd you get parts? How much?

 

Don't remember what I paid for parts--they were Volvo genuine and the price wasn't bad. Ordered the filter, bought the fluid from a local dealer.

Put it all back together, refilled the Haldex fluid, and the AWD still doesn't work. Is there any way to narrow it down any better?

At this point I need to come up with something better than guesses as to why it's not working or I need to abandon the project and sell it to someone who wants to work on it before I end up throwing money away by throwing parts at it. It's a shame because the car has no other issues and is in excellent cosmetic shape inside and out. I replaced a bad CV, bad exhaust cam solenoid, washer pump and tank, rear brakes, fixed the tailgate wiring, etc.

 

I'm having the same issue on my 03 xc70.

 

This is why I tried to say that hearing the pump whirr does not mean it works. If it's plugged like your filter was it may have damage internal such that it won't pass fluid at the pressure needed to engage the mechanicals.

 

Okay, here's where I'm at with this car:

I'm about $2k into it total, counting when I register it Monday. The remaining issues are:

• Rear hatch always says it is open. I think this is because of the harness going back there. It was pretty badly destroyed. Fixed it and resolved most of the other issues, but may have missed a cable. I can buy the whole harness for ~$150 and fix that.
• Pulls to the right--just an alignment, probably.
• Rear brakes need new shoes so the emergency brake works again.
• I may or may not still have an exhaust cam CEL. I took it apart and cleaned it, replaced the gasket, cleared the code. Hasn't come back when idling for 10 minutes at a time in the driveway for a total of probably an hour, plus maybe 3 miles of driving. Will find out when I start driving it if that worked out.
• I need to re-attach the front clip better. Also, the fog lights need bulbs and the connectors are a little messed up.
• The AWD Failure

I believe the AWD has two issues. One was the filter or pressure sensor was causing the Haldex clutch to never engage. I believe I have fixed that. I am not 100% certain, but I think the DEM and everything is now operating properly. Here's why:

Initially, no power went to the rear wheels at all. Also, I heard no noise when spinning the front tires. I pulled the filter and it looked black. I replaced that and the pressure sensor. Now I notice that if I get the front wheels to spin, I have a grinding noise. My theory is that originally the driveshaft was just spinning free because the clutch never got fluid in the rear diff. Now, that's all working again so when it calls for power to the rear wheels it puts a strain on the system and the angle gear grinds.

In addition, I have paperwork on the car from a Volvo dealer and hand written on it is "bevel gear causing driveshaft bearing to go bad."

So, aside from the AWD, I think I have about $500 to go (worst case scenario). Because I'm registering it and will get a new title, I could theoretically resell the car for ~$2k and walk away. Or, I could bite the bullet and spend the extra that it needs. Any input on the AWD failure or anything else?

 

Sounds to me like you really can't afford a decent car.

 

​​​​​​Not at all. I have my truck which is in flawless condition and still books for better than $20k.

I don't need the Volvo, I bought it as a project. Which is why I am having a hard time justifying putting too much money into it.

 

On the grinding noise, it does make some sense to suspect the angle gear. I hope you could be sure by turning the driveshaft with the car stationary. The earlier models had a splined sleeve between the angle and the transmission that went bad.





I have worked on them, but I don't own a Haldex. If I had a 2006 I would be very tempted to get a DICE/VIDA setup to talk to the various computers on the car. If the problem is the gearbox of course this won't tell you anything, but it would be handy for other things.