2005 Ford F150 4.6L P0191 Code: Fuel Pump Driver Module Failure Fix
Mileage: 92,000 miles. My 2005 Ford F150 4.6L engine has been throwing multiple diagnostic codes including C0001, P0001, P0171, and P0174. After a 200-mile interstate drive, the truck began losing power, sputtering, and even stalled several times. I managed to restart it by revving the engine, after which it ran smoothly for a short period. A Ford dealership performed a major tune-up—replacing spark plugs, plug boots, and conducting an induction service—at a cost of $800. The truck ran well for another 200-mile trip, but during a highway passing maneuver, it again lost power and began sputtering. The idle speed was elevated to around 1,000 RPM. The current diagnostic codes are P0191 and P0171. A second dealer suggested the fuel pump might be faulty. However, after further investigation, I discovered that the actual root cause was not the fuel pump itself but the Fuel Pump Driver Module (FPDM), located above the spare tire. This module is known to fail under heat stress, even if it shows no visible corrosion. After replacing the FPDM, the truck has returned to normal operation—running smoothly with no symptoms or error codes. This experience highlights the importance of diagnosing specific modules in older Ford 4.6L engines rather than assuming fuel pump failure. Note: The original P0001 code was reported by a scanner but appears to be invalid for this vehicle model and year. The scanner may have misread or failed to complete the scan. I confirmed that no chip, PROM, or programmer has been installed on the truck—this is a stock vehicle with only routine maintenance history.
Start with a fuel pressure test—it's one of the most common diagnostics for P0191 and related codes. However, some Ford vehicles have been modified or lack Schrader valves, making access difficult. Confirm whether the original P0001 code was valid—some sources list it as P0010 instead.