2005 xc70 dem or aoc pump or both

mrscullini · Post by **mrscullini** » 05 Aug 2015, 20:04

my aoc pump is shot, new one on order. i used the xemodex troubleshooting flow chart and i think the dem is ok. i also have comm between vida and the dem.

the awd is out because of the pump and i am getting a "brake fault" and "engine service" message. if i drive the car in this condition, is there a possibility that i will kill the dem? should i pull fuses 23 & 24 out of the rem. i'll receive the pump next week and plan to install immediately.

mrscullini · Post by **mrscullini** » 06 Aug 2015, 07:15

as i'm reading more threads, another question on the pump. i read that with the car on a lift, so all wheels off the ground, tranny in drive, applying power to the pump should turn the rear wheels. it doesn't seem as though that pump is large enough to turn the rear wheels. it seems the pump's purpose is to move the fluid, not a drive pump.

i ask because when i tested the pump, i was on ramps, the rear wheels could not turn. the pump seemed to struggle and then die out. was this a bad way to test the pump?

also, is there a way to test the pressure/temp sensor? when i check with vida, i was not getting any pressure, however, i was reading temps.

Post by **abscate** » 07 Aug 2015, 06:33

Im not finding AOC or DEM in the glossary - can you write more detail about what problems and parts you are referring to?

Post by **vtl** » 07 Aug 2015, 08:12

AOC is official way to say "Haldex" - variable torque clutch attached to rear diff. DEM is its computer.

mrscullini · Post by **mrscullini** » 07 Aug 2015, 12:45

abscate wrote:Im not finding AOC or DEM in the glossary - can you write more detail about what problems and parts you are referring to?

sorry, AOC is the active on-demand coupling or haldex. dem is the differential electronic module.

mrscullini · Post by **mrscullini** » 07 Aug 2015, 12:51

i got some clarification over on swedespeed. with the car on the lift, engine running and in gear, front wheels should spin. when the pump activates, the rear wheels should spin. the pump feeds fluid to the clutch pack in the haldex.

i'm pretty sure my pump is the issue. i have a pump on order. in the meantime, i have cleared the codes, removed fuses 23 & 24 in the rem (rear electronic module). awd is completely disabled. the only code i am picking up right now is cem-1a64. communication between the cem and dem. which makes sense, the dem in not powered because fuse 23 is removed.

mrscullini · Post by **mrscullini** » 22 Aug 2015, 20:12

i still have an awd issue. my aoc pump was dead and i replaced it today. before replacing, i did run through the XEMODEX troubleshooting procedure to confirm.

today, once the old pump was out, i confirmed it was bad. i also pulsed the new pump with 12 volts, it did index, new pump should be good.

weeks ago, once i knew the pump was dead i pulled fuses 23 & 24 from the REM, i didn't want to chance blowing the DEM. the codes i've been reading thru VIDA (with fuses out) are the following,

CCM-DD12
CCM-DD30
CEM-1A5F
CEM-1A64 (comm to the AOC, makes sense with fuses pulled)
ECM-900B
CEM-9C03

with fuses 23 & 24 in the REM, i get DEM-0006.

spent a good part of the day installing the new pump, fluid, and filter change. reinstalled fuses 23 & 24. after clearing codes and a test drive, i still have DEM-0006, but no CEM-1A64.

now suspect the DEM is bad, but i have comm with the DEM because code CEM-1A64 had gone. i'm a bit confused, any thoughts? tomorrow i will run through the XEMODEX troubleshooting procedure.

BTW, i know the other codes are an issue. i think my brake pedal sensor is also bad, new one on the way.

Post by **doublebug** » 23 Aug 2015, 01:56

Clear codes.
Then in Vida add some DEM parameters in Vehicle Communication.
Start and check them at idling.
Usually Pump current should be around 1.5 A (1500)
Also look at Oil pressure, and Oil temperature and Solenoid current.
Solenoid current after short time usually about 750 (0.75 A).
Oil pressure if everything is good should be about 0.34

Post by **vtl** » 23 Aug 2015, 08:26

Also in the future don't connect PWM (pulse width modulated) receiver to +12, you may kill it.

mrscullini · Post by **mrscullini** » 23 Aug 2015, 08:35

vtl wrote:Also in the future don't connect PWM (pulse width modulated) receiver to +12, you may kill it.

are you talking about the pump?

if so, what are the chances i smoked it? when i pulsed it, it was quick 12 volts, less than a second. i'm confused because this is the same procedure to test the pump when installed and diagnosing this issue.