UEM Connectivity issues after mirror repair

yeahyeah · Post by **yeahyeah** » 19 Oct 2018, 14:53

Having fun getting into the Volvo groove.

Recently purchased 2002 V70 T5 with a sunroof.

Love the car, and I'm working towards making everything 100%.

-The auto dimming mirror had lost it's juice, so after doing some reading here and watching some youtube videos I took the old one out and swapped the glass from an ebay unit into my mirror housing with my circuit board. I broke the first ebay unit's glass in the process and had to get a second one, but that one went smoothly.

-The battery was disconnected for several days in there somewhere waiting for the second ebay unit.

-The battery drained somewhere in the process and I had to jumpstart the car after getting everything put back together.

-Once back together, i had no dome lights or reading lights, the alarm doesn't sound if i intentionally set it off (lights flash, but no siren) and the sunroof doesn't work.

-Plugged in a chinese vida-dice unit (after a few days getting it working) and i'm not getting any signal from the UEM. CEM is throwing a code "CEM-1A5C Communication with UEM control module Signal missing"

-I'm not able to activate anything in the UEM from VIDA.

-Pulling the UEM fuse while the car is running and then plugging it back in gave me dome/reading lights by manual push button only, not activated by turning car off or opening doors. So i'm sure power is getting there, the network just isn't reading it. Still no sunroof though.

-I have attempted different "UEM reset" options i read about online:
1) lock unlock three times with key in driver's door (doors lock and unlock, but nothing magical happens)
2) key in position two, hold up window levers 6-8 seconds, turn off key, lock, unlock, lock unlock (i read to do this with key fob, but i don't have a key fob so i used the door button)
3) I read that you could force a UEM reset through vida, but i can't seem to find the option that was described, so i haven't done it that way.
4) Tried to reconfigure the siren via vida, it fails

I'm enjoying the challenge, but i also just want to fix this and move on to rebuilding suspension and hand brakes.

Thanks

Post by **mrbrian200** » 19 Oct 2018, 15:47

I'm thinking along the lines of
A) accidentally zapped it with static electricity while working on it, or most likely..
B) disturbed a weak solder joint or broke circuit trace while manhandling to replace the LCD/adhesive.

yeahyeah · Post by **yeahyeah** » 19 Oct 2018, 16:10

mrbrian200 wrote: ↑19 Oct 2018, 15:47 I'm thinking along the lines of
A) accidentally zapped it with static electricity while working on it, or most likely..
B) disturbed a weak solder joint or broke circuit trace while manhandling to replace the LCD/adhesive.

that's what i'm afraid of. would it be worth trying one of the other circuit boards i now have? being that i don't have a key fob anyways i would at least have dome lights and sunroof right?

is there a particular part of the board i could try to transfer over to one of the other cards to keep my car's info or does it need the whole thing?

Post by **precopster** » 19 Oct 2018, 16:39

Do a proper battery connect with key in PosII and then connect negative lead THEN lock/unlock driver's door 3 times.

I have used the remote for the lock/unlock sequence many times with success and had zero problems.

As you don't have a remote check this in Vida:

1) Go to Diagnostics: then Network then click on UEM icon. Do you get serial number, part number, diagnostic version and 2 x software part numbers?
If you get the numbers the UEM is operational.

2) If not go to Software then Advanced
Click on the drop down list choose UEM then click Send Program.

Then choose Read Hardware Number and Read Serial number. If they don't show the module is dead.

Exit the program by choosing Send Reset.
____________________________________________________

With the used UEM you have, perform Network check for readable parameters as in Step 1 HOWEVER FIRST LOG OUT OF VIDA THEN LOG IN AND CHOOSE UPDATE. If all the items appear as above the used module is OK. If not perform Step 2.

Report back and we'll try to help.

yeahyeah · Post by **yeahyeah** » 19 Oct 2018, 17:55

precopster wrote: ↑19 Oct 2018, 16:39 Do a proper battery connect with key in PosII and then connect negative lead THEN lock/unlock driver's door 3 times.

I have used the remote for the lock/unlock sequence many times with success and had zero problems.

As you don't have a remote check this in Vida:

1) Go to Diagnostics: then Network then click on UEM icon. Do you get serial number, part number, diagnostic version and 2 x software part numbers?
If you get the numbers the UEM is operational.

2) If not go to Software then Advanced
Click on the drop down list choose UEM then click Send Program.

Then choose Read Hardware Number and Read Serial number. If they don't show the module is dead.

Exit the program by choosing Send Reset.
____________________________________________________

With the used UEM you have, perform Network check for readable parameters as in Step 1 HOWEVER FIRST LOG OUT OF VIDA THEN LOG IN AND CHOOSE UPDATE. If all the items appear as above the used module is OK. If not perform Step 2.

Report back and we'll try to help.

So... step one shows no info, the UEM is grayed out, not showing up as anything. hardware and serial number are non existent... i'm pretty sure it's dead. Send prog and send reset did nothing. swapped in one of the other UEM units (outside the mirror, just pulled the wire and hooked it into the other PCB). Now network can see the device number and serial. Still have a communications error on the CEM. Now I have a UEM error too "rain sensor signal missing". I can turn the dome lights on and off from VIDA, but they don't turn on for door opening or key turning off. Initially I could turn the dome/reading lights on and off from the buttons, but that stopped after about 10 minutes. Sending reset, or lock/unlock sequences still don't seem to do anything to improve my situation.

I'm open to more ideas, but i'm thinking at this point I probably wasted $75 on ebay mirrors, and should have been more careful with my disassembly. I hate to reward volvo with $600 (edit: actually it's $1000 plus labor) for their behavior of hiding computers in mirrors

Think i should send this whole pile to xemodex?

yeahyeah · Post by **yeahyeah** » 19 Oct 2018, 18:30

second question on my mind now that I called my local dealership and got quoted $1000 for a mirror replacement:

how much useability could I expect out of replacement UEM from one of my ebay units if my original is dead? any chance of getting the sunroof and dome lights to work?

yeahyeah · Post by **yeahyeah** » 19 Oct 2018, 19:08

or maybe my best bet is buying a brand new genuine mirror for $400 and installing the software myself with a three day vida subscription?

sorry for the fast repeat posts. i get obsessive when i can't solve a problem and i'm digging for solutions.

Post by **precopster** » 19 Oct 2018, 19:10

OK so 2nd UEM is operational because you get a Network response. That's a step in the right direction. I'm pretty certain the subscriptions are limited to a licensed copy of Vida and a genuine Volvo Dice unit (the Volvo server looks for the Dice serial number)

Contact MVS user Yagger (Sergey) memberlist.php?mode=viewprofile&u=90461
and he should be able to log into your car and try to reload the correct software configuration for your UEM by using your Dice.

yeahyeah · Post by **yeahyeah** » 23 Oct 2018, 19:43

precopster wrote: ↑19 Oct 2018, 19:10 OK so 2nd UEM is operational because you get a Network response. That's a step in the right direction. I'm pretty certain the subscriptions are limited to a licensed copy of Vida and a genuine Volvo Dice unit (the Volvo server looks for the Dice serial number)

Contact MVS user Yagger (Sergey) memberlist.php?mode=viewprofile&u=90461
and he should be able to log into your car and try to reload the correct software configuration for your UEM by using your Dice.

thanks for your help. i managed to repair the circuit board with a razor blade, solder iron, some liquid electrical tape, and a lot of luck. i'm back in action now, all systems seem to be functioning with the original UEM and the new glass. Hopefully the repair holds.

Ldordai · Post by **Ldordai** » 21 Jan 2024, 13:38

I know this is 6 years later, and hate to thread revive…but I am having a similar issue. I ended up replacing the capacitor that is known to fail on these. After reinstalling, I still have no communication with the UEM. When I go into diagnostics and network, the UEM is red and not greyed out, but when I go the software and advanced route, I can’t pull the serial or part number thru the method listed.

I did do a canbus continuity test at the OBD2 port, and am getting high ohms (about 115) on the low speed network. My guess is there is an issue between the SRS unit and the UEM, because the SRS unit is green and commuicating just fine. Can anyone provide me some direction of where I should be looking, and what body panels I should be releasing to get where I need to get?