AWD Problem

**Gazdok** · 06-07-2011, 05:29 AM

Hello I am new posting on this forum, but have been reading across forums for a while.
I have a V70 AWD from 2006 - Haldex III - and have had a problem with the Anti Skid service light coming on sporadically and then regularly after a few miles.
Often when the light comes on there is a little shudder or bang noticeable when going straight.
When I corner on full or fairly full lock I can feel the car binding with a lot of vibration and then a bang and the tension in the drive train is released.

I have spoken to my local Volvo dealer who diagnosed the car and said DEM change please. I sent the DEM off for repairs and it came back with no fault found.
I also changed the temperature and pressure sensor.
I had the car on a ramp and there the AWD was working.

Now I have been reading about the Haldex and it said that the pressure in the clutch is released when the brake light or the hand brake light is triggered even way before the car is actually braking.
I tried the handbrake carefully when I was on full lock and the vibrations started again and there was this bang again and the binding and tension gone immediately.

Has anyone had problems with their car binding on full lock and what was the problem?
Is this pointing to a faulty pump or choke valve in the Haldex coupling?

**kamiar** · 06-07-2011, 10:07 PM

Do you get any codes related to brakes? start with simple things, maybe your ebrakes are gone bad and stick so the haldex releases or maybe a bad sensor, also check the front sensor ring around the CV joints

**tapanitja** · 06-07-2011, 10:32 PM

Hi, what's your mileage? have you ever changed haldex oil and filter?
Haldex service is not in V's programs but I plan to change oil & filter now when 110kkm are past to see the used oil quality for future service plans.

Don't know what else could be done to prevent problems.

Having had 2x850-94s changing the autotransmission oil has kept them going without problems.

br Tapsa

**Gazdok** · 06-08-2011, 03:33 AM

Since I had these problems I got a VIDA Dice. When I check the DTCs I regularly get a BCM-0095 and either a DEM-000B or DEM-0006.

The BCM-0095 suggests that there is a communication problem between BCM and DEM. There is a difference in wheel speed measured / indicated between front and rear axle. When I had the car on a ramp I was getting faults for wheel speed sensors for both rear wheels. BUT that was the only time ever that these DTCs came up. The rear wheel seemed to be going at different speeds to the front.
VIDA says that the DEM should be faulty and has to be replaced.
When I had the DEM checked it came back ok.

DEM-000B suggests that there is a problem with the oil pressure in the AOC.
This could be caused by a faulty Temp/Pressure sensor - replaced alreday-, A DEM problem or a faulty AOC clutch.
On the ramp I noticed a subtle whining / whistling from the prop shaft / AOC clutch area but could not locate it any closer.
I also checked the actual AOC oil pressure read outs and they were with in normal parameters with the engine on and wheels spinning and also with ignition off.

I had DEM-0006 only once in connection with the wheel sensor faults. DEM-0006 suggests a faulty pump signal.

AOC pump and air filter change are next on the cards. I checked the oil and that is still nice and clear and the level was o.k.

My mileage is 47000.

The wheels rotate free when in the air. I do not think the brakes stick. There is no excessive heat from the hubs after driving.

When I changed the wheels from winter to summer I took the wheel sensors off to check them and put them back. They were fine. CV joints ok.