2006 XC70 - Christmas :-/ Topic is solved

daandus · Post by **daandus** » 28 May 2020, 15:11

Dear all,

So... my XC70 decided to mess with me a little - so far it is winning!

While driving away at traffic light, it freaked out.
- Dials (spd and rpm) to zero.
- Tranny to "-" and in limp mode (3rd gear or something?)
- "Brake failure - stop safely" on the dash.

Managed to keep going, clear some codes with OBD later on - and after a few attempts to turn off and start the car again it was all good for a bit.
Then CEL came on: engine service needed - and when I parked in the garage - Immobilizer Read Manual....

OBDII gives codes:
P0503 ABS sensor speed
U0002 High Speed can error
P0700 PCM transmssion failure
P0863: Transmisssion comm failure
P0600: Serial link error.

I luckily have a VIDA/Dice:
BCM-0065 Stop (brake) lamp switch Signal outside its
permitted range
BCM-0150 Stop (brake) lamp switch Signal outside its
permitted range
BCM-E000 Control module communication Faulty
communication
BCM-E003 Configuration fault Faulty configuration DTC is found active.
CEM-DF13 CAN-H, high speed network Signal too high DTC is found active.
CEM-1A5F Communication with BCM control module
Signal missing
CEM-1A61 Communication with TCM control module
CEM-1A62 Communication with ECM control module
Signal missing
CEM-1A64 Communication with AOC control module
Signal missing
CEM-3F83 Immobilizer signal Signal too low DTC is found not active.
CEM-DF16 CAN-L, high speed network Signal too high DTC is found not active.
CEM-DF17 CAN-H, high speed network Faulty signal DTC is found not active.
CEM-E000 Communication with control module Faulty
signal
DDM No fault found
DEM-E000 Control module communication Faulty
communication
DIM No fault found
ECM-710B Immobilizer communication - Signal missing DTC is found active.
ECM-E000 Control module communication - Faulty
communication
ECM-120D Air mass - Signal too low DTC is found active.
ECM-900B Brake pedal sensor - Signal missing DTC is found active.
ECM-A12B Speed signal - Signal missing DTC is found active.

Now, I deal with CanBus systems at work occasionally - and it seems to me that the CanBus looses power, or has a shutdown - and all the other trouble is just a result and limp-mode and such.

With my previous XC70, i was advised by Volvo that batteries only last 4 yrs, then the car can 'freak out' when they are older with all kinds of trouble.
So, I charged it up on a charger and it works for a bit - my documentation tells me the battery is 4yrs old.
I then installed a battery (also few years old...) from my other car in it - and it ran fine for 3 days on approximately 8 short trips! I was HAPPY!
Just bought a brand new battery, and while driving away (battery not installed yet), the whole thing freaked out again - same errors.
It limps home

Checked most fuses, wiggled most relays.
I took the CEM out to inspect for water damage - seems all dry and no corrosion or anything that I can see on connectors.

I'm a little lost here - as it could be anywhere from a bad relay to busted electronics.
As you can imagine, I hope for the relay

I have not installed the new battery in it as now I can still bring it back - it cranks/starts fine on both 'old' batteries.

Currently it just says 'Brake Failure' and 'Immobilizer - see Manual' - and won't start at all. (I tried the 5x unlock and the panic button, no change)
Canbus measures 62ohms...

Any help greatly appreciated, thanks in advance!!

Post by **yagger** » 28 May 2020, 15:35

Check CEMs top connectors for water damage.
Also, sometimes DEM can affect on it.

daandus · Post by **daandus** » 28 May 2020, 15:53

Thanks Yagger!
I took the CEM out - super dry and no trace of water or anything. Connectors seemed fine too.
DEM - I have not looked at yet - perhaps easy to take off and inspect.

When the car runs, everything works, including AWD and ABS and such....

Post by **oragex** » 28 May 2020, 16:33

This is a tough little one, go step by step, don't rush replacing modules. Be careful with the Volvo dealers, may be easy to suggest $$ repairs without results in such scenarios. Some may still be helpful, but others it's the kind of moment they go for skimming
See as above if the DEM has lots of corrosion at the lower metal side - don't need to remove just support the car safety (NOT with the spare jack, use a jack stand), and look at the DEM. Corrosion on it doesn't necessarily mean problem, but it's a check point (Xemodex does these)
Also disconnect the battery for 30 min and measure the voltage. Measure with the engine at idle as well
Inspect cables near battery, starter, engine bay fuse panel, trunk behind the battery
Genuine batteries have been lasting well over 10 years, you can get an EverStart Maxx from Wally, top quality
While there, remove the alarm siren fuse (I have a video on my channel to locate it)

Post by **yagger** » 28 May 2020, 16:36

I think, you can try to disconnect connector from DEM and use car without AWD option for test. But in my mind, need to open DEM and check it for water or oil damages.

daandus · Post by **daandus** » 28 May 2020, 16:44

Thanks, i have the DEM off now but cannot get the connectors off... Is that unit able to be opened and see circuit board? Or just check corrosion on connectors?

Thansk a lot for your help!

Post by **yagger** » 28 May 2020, 16:48

There are very crackable locks on that connectors, be careful.

download/file.php?id=37682&t=1
damages can be like this

daandus · Post by **daandus** » 28 May 2020, 16:53

Thanks - I saw some similar pics at xemodex..... pretty ugly!

How does the aluminium cover come off off the DEM unit?
I'm in doubt whether t open it up or not.

I really like the suggestion to drive around with the DEM disconnected - to eliminate the possibility of it messing up the CAN bus.
The car ran fine in between 'freak-outs' for days - so fault finding may take a while.

Battery life: it had a genuine VOLVO battery in, 4 years old. Starts just fine....
I struggle to believe that causes my grief (as it does the same now with another battery, not new).
I have put it on the charger numerous times - then it drives okay for a bit. Can also be wait time I guess, and not charging of the battery?

Thanks to all for the help!!!!

daandus · Post by **daandus** » 28 May 2020, 17:09

Put it back together, reconnected battery.
No codes. (DEM still connected)
Car started, right away came back brake failure message. Then it stalled.
Tried to start again, crank but not start (that is a first).
Off/on ignition, immobilizer message, wont crank anymore.

Post by **yagger** » 28 May 2020, 17:12

Do you have some immo errors with disconnected DEM?