2006 xc70 CEM or central brain RESET ??

[BryonTheCanadian]

how does one reset the CEM? i heard someone say touch the positive and negative terminals together/

[jimmy57]

Many of the modules have capacitors that stabilize voltage during expected and unexpected voltage deviations in the power supply voltage. Those caps will keep the module from going completely offline for days if battery is disconnected. Open tailgate and run something through tailgate latch port to move the latch and thus the position switch to closed position and then have all doors closed (the tailgate will have closed status from that step). Wait 5 minutes to assure the shutdown activities have completed and then remove ground lead. Touch or bridge with wire the ground to the pos post. This drains those caps. Hold the connection for 10 seconds at least.
Now reconnect everything. The modules have all done the car computer version of reboot. You will have to use remote to lock and unlock to exit the trnsport mode that shuts down operation of several things on the car to keep battery drain low for weeks at sea when car is shipped to US. There are many battery reconnect procedures I have read. The wait 5 and disconnect is the VIDA process. Closing tgate latch and all other doors and hood will make the car go to "sleep" more quickly by speeding up the extended power on for audio and some other accessories. There is a battery reconnect procedure where key is turned on and then the ground lead is connected. This is airbag safety. You can't be injured by any of that stuff while you are attaching grd lead and the system deploys things in error. The original placement of his process was only in SRS repair steps but it has been moved to the general battery connection process. You could also close your gas main and open and release all the natural gas in lines and appliances every day when you leave for work. I think natural gas explosions happen at a greater rate that unprovoked, no SRS faults, no submerged in 3 ft or more or water Volvos. Even the ones with the preceding issues don't blow SRS components at any rate.
There are some things found somewhere about connection procedures to avoid CCM death. I have been in the Volvo fixing biz for decades and CCMs and some other modules will not come back online without some fuss when the disconnect process is not done where the systems are down when the battery is disconnected. Some modules just die because they die and they die when everything is done right.

You asked for the time and I told you how to build a clock....sorry.

[oragex]

Make first sure you can open the car with the door or trunk barrel if you lock the car with the battery disconnected.
If I undo the negative post overnight, next morning I would see no lights on the fan knob - this means the CCM was 'reset'.
Have the ignition key in POS II when reconnecting the battery (headlights on).

However this does nothing if the CCM needs be calibrated. Is there an issue with it ? to

[BryonTheCanadian]

Yes radio, 12 volts plugs, passenger seat, rear back up sensors are dead, dealer thought it maybe CMU related.. CMU/CCm i mean the main control brain seems to go by many names.. I want to reset it and see what happens.. thats the cheap easy fix

[jimmy57]

CEM is the main controller on car that runs lighting and alarm and does roll call and on and off commands to the other modules. CEM is under left side of dash and on a 2006 it is L shaped and the top is under a cover in the cowl area where wiper motor and linakge hides. CCM is the climate control module which is housed in the climate panel with fan and temp knobs.

[BrRa1735]

I have a 2005 XC90 and replaced the CEM. This alleviated the electrical issues I was having but now the car won't start. How do I fix that?

[vtl]

You had to clone your old CEM to donor unit. XeMoDeX or cheaper ebay options.