@T5-T6-Schnappi said in S60 - catalytic converter low efficiency.:

@Leinth the absolute fuel pressure should be around 480+-5 kPa or 380+-5 kPa relative pressure at idle RPM, transmission in neutral and warm engine, and the duty cycle of the fuel pump should be around 50%+-10%.

I do not have VIDA or vdash to check for this, the one i have only shows "fuel pressure" which was ~386 at idle and it had nothing on duty cycles for fuel pump. There is a plan to service the car this month so I will ask them to remove the spacer. Will see if P0420 returns and the lean code(forgot the number again) disappears.