CEM Failure Symptoms

Post by **br0dy519** » 20 Jul 2021, 19:17

Hey guys, I've noticed when connecting my DiCE sometimes I'm unable to read the vehicle. Sometimes it connects yet all modules show no communication. Sometimes, I actually get a "BRAKE FAILURE" message on the DIM when running DiCE when everything connected ok. I've never received the BCM fault in normal vehicle usage. The other day when I was running VIDA my car randomly started idling ~1000RPM and I got a P0507 code. That was the first time that ever happened. Also in the past I have seen CEM-E000 show up in the fault code tree.

Is any of this normal behavior, and is any of it evident of a bad CEM? It seems to act funky when it has the load of DiCE running on it. It is a 2004... I've been using dice more lately to try and chase my engine surging issue hence seeing the issues crop up while troubleshooting.

Post by **jonesg** » 21 Jul 2021, 01:40

2004 v70,

ABS lights up whenever I connect VIDA, but goes away once I unplug the dice.
Thats usual behavior with mine.
I don't run the engine , I just put the battery charger on it when connected.

Post by **oragex** » 21 Jul 2021, 06:06

I was getting a "brake" message when connected, it was a faulty relay but I had the older 01-03 CEM model. People were saying this could be because of a BCM "partial" internal issue. For the CEM the easiest is to look with a flash light under the dash for dry traces of water on the module. You may also try to look outside at the connector, but need to remove the wiper arm which most probably is badly stuck - don't wiggle to remove, it takes a strong wiper puller

Post by **vtl** » 21 Jul 2021, 08:05

Volvo's CAN-bus troubleshooting: http://www.s80.dk/Billeder/2010-05-26_205437_088051.pdf

Post by **kallekula** » 21 Jul 2021, 11:06

One test could be to use a hair blower on the CEM and see if your problems arises faster. If it's not a permanent error ofc.