Need advise about 4C service Required Message

[KurtL]

I own a 2005 V70R and had a leak on my front passenger side 4C shock so I replaced both fronts.
After I got the service message i replaced both rears at 120K miles. I still get the same message. I figure the next step is to replace the electronic module. Are there any suggestions on what to do? Could it be a bad sensor somewhere?