No AWD and no codes 2005 xc70

crazycat · Post by **crazycat** » 29 Dec 2019, 15:17

No AWD and no codes on my daughters '05 xc70.
Vida DEM parameters read:

.38MPa oil pressure
1900mA pump current
9 mA of solenoid current

I remember seeing a temperature reading as well, which leads me to think the pressure/temp sensor is good, but didn't pay attention to them.
I want to think it's what Vida calls the control valve/axial solenoid? I can't find a part number for this piece? Maybe it could still be the DEM board? But with all the communication I have I'm hoping not. I haven't even changed the filter or oil yet. Just discovered it wasn't a sheared collar sleeve this past weekend by doing a drive over of my iPhone shooting video and saw the driveshaft turning.
Thank you for any input or advice.

crazycat · Post by **crazycat** » 14 Mar 2020, 11:45

Got some more info..
Solenoid current looks good now but
DEM-CEM voltage is 0 ??

Vida says :

Central electronic module (CEM), voltage

The value indicates the voltage over the Central Electronic Module (CEM).
The control module transmits the signal on the controller area network (CAN) and the Differential Electronic Module (DEM) uses the signal to diagnose the power supply.
Measurement range: 5-30 V

———————

Voltage over the CEM ? I’m not sure what this means or where to look for the problem.
Connector plug ? Wires ? Could this be internal damage in the DEM or possibly corrosion at the CEM?
Thank you for any help

Post by **jimmy57** » 14 Mar 2020, 12:09

The drive over test wouldn't find a faulty AG sleeve. The AOC (Haldex made unit on front of rear diff) will have enough fluid pressure to lightly apply the drive clutch and then rear wheels would turn driveshaft. With rear wheels on ramps so you can get under car, have it in Park with key off and then use a rag over driveshaft and large slip joint pliers to turn the driveshaft. If it turns then sleeve is the problem. The rag is only to prevent scratches so it is optional if driveshaft appearance is not high on your list of important things. When you turn driveshaft it may slip and catch as the splines on collar catch and then go by the drive splines for collar. It is possible for the angle gear to fail and cause no drive but I have not seen that without loud growling noise for many miles before it fails. Usually AG failure can be felt.

Post by **vtl** » 14 Mar 2020, 13:24

Please read the codes and attach screenshot with all codes, even inactive (yellow).

crazycat · Post by **crazycat** » 14 Mar 2020, 14:13

Thanks guys! Makes total sense about the drive over test being garbage. As soon as I have possession of the car again I’ll check that driveshaft. We purchased it with nonworking AWD. Its never made a noise, only a yellow skid warning flashes, on right side of cluster, while actively slipping. Possibly a message in info window too I don’t remember. Any idea why that DEM-CEM voltage in the vehicle communication parameters in vida reads zero?
Codes pulled last weekend:

Post by **vtl** » 14 Mar 2020, 14:32

ECM-439C is either a cracked rubber ring on fuel filler cap or a dead EVAP test pump.

No common communication errors. At this point I would check the collar sleeve as others already suggested.