S80 2001 REM (CEM) failure
Thread Starter
|
Junior Member
Joined: Oct 2023
Posts: 2
Likes: 0
S80 2001 REM (CEM) failure
Hi! I hope someone has some information of how to continue!
Car: S80, 2.4 (170), 2000.
Background: I got the “famous” problem with bad connections at the border to the CEM unit for the shunt to the low beam. The fix was rather easy, pull out the CEM unit and replace the burned cable together with a new connector and put back the shunt and the a few nearby relays. In doing so, I thought it was no danger of short cuts so I did NOT(!) disconnect the battery. (Actually the true CEM unit was not tuched, only the circuit bord around it.) However, starting the car I received a lot of warnings, like ABS, SRS and so on. So apparently I have interfered with the computer despite my carefulness. However these disappeared after a minute, but the fuel guage, rear central locking system (back doors, trunk etc) has remained dead.
Problem: It seems like the REM (all electrical things in the back) is from that time dead.
Looking for errors:
1. Disconnecting the battery for 5-10 minutes brought the system on line for 10 seconds then died again.
2. Carefully inspecting the CEM unit without any noticeable problems.
3. Disconnected the battery for 8h and the system woke up and remained working for approximately 5 minutes during the test drive. And then died again.
4. Checking the battery and reads 12.0V and the same voltage at fuse no1 (upper left row at the REM-unit). Starting the car and both places reads 12.8V.
5. Removing fuse 1 and 2 (upper left row, REM-unit) for 30 minutes and put them back while the car is running (thinking of too low voltage to wake up the REM unit) and the rear electrical system went to live for 10-15 seconds, again.
In conclusion: All electrical parts seams working fine, except the electrical things from REM. And since It woke up a couple of times, this must be something that others has experienced?? Please any help of how to continue and what to do is if help! Thanks in advance!
/Jimmy
Car: S80, 2.4 (170), 2000.
Background: I got the “famous” problem with bad connections at the border to the CEM unit for the shunt to the low beam. The fix was rather easy, pull out the CEM unit and replace the burned cable together with a new connector and put back the shunt and the a few nearby relays. In doing so, I thought it was no danger of short cuts so I did NOT(!) disconnect the battery. (Actually the true CEM unit was not tuched, only the circuit bord around it.) However, starting the car I received a lot of warnings, like ABS, SRS and so on. So apparently I have interfered with the computer despite my carefulness. However these disappeared after a minute, but the fuel guage, rear central locking system (back doors, trunk etc) has remained dead.
Problem: It seems like the REM (all electrical things in the back) is from that time dead.
Looking for errors:
1. Disconnecting the battery for 5-10 minutes brought the system on line for 10 seconds then died again.
2. Carefully inspecting the CEM unit without any noticeable problems.
3. Disconnected the battery for 8h and the system woke up and remained working for approximately 5 minutes during the test drive. And then died again.
4. Checking the battery and reads 12.0V and the same voltage at fuse no1 (upper left row at the REM-unit). Starting the car and both places reads 12.8V.
5. Removing fuse 1 and 2 (upper left row, REM-unit) for 30 minutes and put them back while the car is running (thinking of too low voltage to wake up the REM unit) and the rear electrical system went to live for 10-15 seconds, again.
In conclusion: All electrical parts seams working fine, except the electrical things from REM. And since It woke up a couple of times, this must be something that others has experienced?? Please any help of how to continue and what to do is if help! Thanks in advance!
/Jimmy
Super Moderator
Joined: Mar 2012
Posts: 9,601
Likes: 540
From: Burlington, VT
The CEM (central electronics module) can develop cracks in the solder connections or the onboard relays can fry. If you suspect the CEM has failed, check out Xemodex.com and midwest-abs.com as they repair Volvo modules. If they rebuild your unit there's no concerns about reprogramming or pairing to the ECU.
Thread Starter
|
Junior Member
Joined: Oct 2023
Posts: 2
Likes: 0
Thanks for replying and suggestions.
Since I worked only on the shunt for low beam and everything was fine before and afterwards the REM (fuel gauge, rear central lock system … ) was the only thing that did not work. I have now looked at fault codes, can this be of any help since I can not make anything good out of it.CEM: Error code: “E001 State: None. Control module communication. Faulty connection. “Real time reading: “Read 50-Supply = LOW, Read S-Supply’=High, Read X-Supply=High, Read 30-Supply=13.49V.Link ERROR or not found for modules: REM, RTT, SWAS, FSCS, ECM, TCM, AEM.
Can ”Read 50-Supply” be a clue? =(
Thx!
Since I worked only on the shunt for low beam and everything was fine before and afterwards the REM (fuel gauge, rear central lock system … ) was the only thing that did not work. I have now looked at fault codes, can this be of any help since I can not make anything good out of it.CEM: Error code: “E001 State: None. Control module communication. Faulty connection. “Real time reading: “Read 50-Supply = LOW, Read S-Supply’=High, Read X-Supply=High, Read 30-Supply=13.49V.Link ERROR or not found for modules: REM, RTT, SWAS, FSCS, ECM, TCM, AEM.
Can ”Read 50-Supply” be a clue? =(
Thx!
Thread
Thread Starter
Forum
Replies
Last Post
JenniferXC70
2001-2013 model year XC70
7
Oct 25, 2022 10:46 PM
mr.poderosa
Volvo S80
0
Jun 21, 2016 04:53 AM
