2005 Volvo s40. Sometimes it runs just fine then it gets sluggish and receive ant skid service message , brake failure pull over slowly, and all the dash lights will come on and off now it doesn’t start saying immobilized ( the key) I’ve only had one key ever. Randomly the blinker comes on by itself and not turn off as well as the windshield wipers. I can pull some tricks and get it started but what could it be?

 

Your first step should be a scan with a compatible scanner that can talk to all of the control units.

Water damage to the CEM could be a possibility since you have a bunch of random stuff - But a rational diagnosis should be done before considering that repair. If there is a water leak that needs to be solved also.

xemodex can repair your CEM if needed more reasonably that a new one from Volvo. A new one requires a software download using VIDA to make it work.

https://xemodex.com/us/product/volvo...tronic-module/