Very common fault for Volvo P1 cars (C30 / S40II / V50 / C70). Official way how to fix this eeror is replace the SRS unit by Volvo dealer for approx 800,- Eur. VDASH can fix this error via OBD without any harm of airbag system (all will work like if you replace the ECU).
This fault usually happen when the car battery is low / damaged or if the charging system has some fault (check alternator / contacts).
How to fix this SRS-CFFF fault?
1/ connect your car with VDASH
2/ on the diagnostic screen sellect button SRS-CFFF fix
3/ load the software
The whole process takes approx 5-min and you don't need to disassemble anything!