I am having issues with a passenger low beam that is not getting power. I have an aftermarket Pioneer radio that I installed a few months back. Everything seemed fine (from the harness and wiring I could tell the previous owner likely had an aftermarket system as well - and I assumed the "remove radio" software update had already been installed)...is it possible the the radio is just now causing the CEM to freak out? Electrical issues drive me nuts, especially in a car with so many computer systems.

 

yes, the radio could cause a cem to offline. but in your case, i don't think the radio is the problem cuz you been driving your car for a few months w/that radio already. usually if the lin network went down it would take less then 10 key cycle then the whole network is down. after driving a few months, i don't think so.

 

sadly, as I assumed it would be, it was the CEM. Pricey fix for a headlight. I am somewhat surprised Volvo allowed such an integrated, non-serviceable system for something as critical as the headlights given their reputation for safety.