Car is gone for the weekend. Car came in with P0172, rich, ran fine, fuel pressure with a gauge 58 psi. Am familiar with fuel pressure sensor issues on Volvo. No misfires. LTFT -25 at 2500 rpm. Searched here, found reset is a common fix, worked for us. Question is, using our Modis, looking at data, on the OBDII side of the brain FP read 58. On the Volvo side there was "Fuel Pressure" which read 73psi and "Fuel Pressure (rel)" which read 58. Is one a calculated value? Which one is the actual? Why two PIDS??? If the first one is actual, we likely have a bad rail sensor. Just wondering in case it acts up over the weekend, we gave it a 2 mile ride after a long idle, LTFT wound up +7 idle ( a bit high) driving at 40 mph was 0 to + 1.7.

Frederick Vinhateiro
Owner/Technician
Fred's Service Center Inc.
Riverside, Rhode Island, USA