P0191 on Ford: How to Diagnose & Fix
Fuel Rail Pressure Sensor Circuit Range/Performance
3 Ford models · 3 documented issues · 2 critical · $150-$12,000 repair
P0191 on Ford by model: symptoms, diagnosis and fix
The 2011-2016 6.7L Power Stroke uses a Bosch CP4.2 high-pressure fuel pump, which is lubricated by the diesel fuel passing through it. When the pump wears internally, it sheds metal particles. The pump feeds fuel to the injectors at very high pressure, so those particles can be carried into the injectors, fuel rails, high-pressure lines and the return side of the system. A diesel parts seller describes some early CP4 failures as sudden ("grenade") failures that send debris through the whole fuel system, and says flushing and cleaning will not restore it. Owners have sued Ford over the pump. The lawsuits claim the CP4 design is fragile and incompatible with U.S. diesel fuel, which they describe as low in lubricity, and that Ford knew this and did not disclose it. Ford disputes that the pump is defective. It says the pump was adequately designed and tested, and that failures can come from causes such as contaminated fuel. In Droesser v. Ford (E.D. Mich., No. 2:19-cv-12365), the court certified classes in California, Louisiana, Ohio, Pennsylvania and South Carolina on September 30, 2026. The classes cover owners of 2011-and-later 6.7L trucks who paid out of pocket for a CP4 repair. That ruling does not find Ford liable, and there is no settlement, payment amount or claim process yet. Once metal has spread, the repair usually means replacing the pump, injectors, rails and lines. One diesel shop reports that dealer bills for this job routinely run $8,000 to $12,000.
Common Symptoms
- Loss of power during acceleration
- Engine hesitation and stumbling under load
- Hard start, or cranks but will not start
- Fuel rail pressure too low codes (P0087, P0191)
- Check engine light with fuel system pressure codes
- Metal particles found in the fuel filter
- Engine shutting off while driving
How to Fix
Check first: if the truck is hard to start, cranks but won't start, loses power, or sets a fuel rail pressure code, have the fuel filters checked for metal. A diesel shop advises cutting open the return filter and inspecting the media. Metal in the filter means the pump is failing or has failed. If metal is confirmed, Ford sells a complete Motorcraft fuel system contamination repair kit. The part number depends on the truck: - 2011-2014 trucks (build dates 2/22/2010 to 3/17/2014): EC3Z-9B246-C. It includes a CP4 pump, 8 injectors, both fuel rails, and the high-pressure and return lines. - 2015-2016 F-250/F-350 pickups: FC3Z-9B246-F. It includes the CP4 pump, injectors, both rails, fuel lines, and the fuel pressure regulator and sensor. It does not fit cab-chassis trucks. Confirm the right kit for your VIN with a Ford dealer. Online sellers list the kits at roughly $3,400 to $5,300, plus a refundable core charge and labor. One diesel shop reports that dealer bills for the full job routinely run $8,000 to $12,000. Coverage: you may be a member of the certified class in Droesser v. Ford if you bought your truck in California, Louisiana, Ohio, Pennsylvania or South Carolina, paid out of pocket for a CP4 repair, did not sign a dealer arbitration agreement, and have not already been reimbursed by Ford. No settlement or claim process exists yet, so keep all repair invoices. Risk reduction is up to the owner, and none of these are Ford repairs. Some owners add a diesel lubricity additive. Others fit an aftermarket "disaster prevention" kit, which is a return-line filter and bypass meant to contain debris. It does not stop the pump from failing. A third option is replacing the CP4 with a different pump, such as a Stanadyne DCR-style conversion.
Sources for this issue (9)
- Ford Super Duty Fuel Pumps Are Defective, Claims New Class Action Lawsuit - Ford Authorityarticle
- Ford Power Stroke Lawsuit Filed Over Defective Fuel Pumps - Ford Authorityarticle
- 6.7 Powerstroke 2011-2014 CP4 Fuel Pump Failure / DEF Contamination Kit - Motorcraft EC3Z9B246Carticle
- Ford Diesel CP4 Fuel Pump Class Action: Five Classes Certifiedlegal
- Ford class action alleges certain diesel trucks contain defective fuel injection pumpsnews
- What Is a CP4 Disaster Prevention Kit for a 6.7L Power Stroke?repair-shop
- Ford Powerstroke 6.7L Catastrophic CP4 Failure Kit (2011-2014)parts-listing
- Ford Motorcraft Fuel System Contamination Repair Kit, 2015-16 F-250 & F-350 6.7L Power Stroke Pickupparts-listing
- OEM 11-14 Ford 6.7L Powerstroke Diesel Fuel Contamination Repair Kit - EC3Z9B246Cparts-listing
2004-2009 Ford F-150 (11th-generation) suffers from Fuel Pump Driver Module (FPDM) corrosion. The aluminum-housed module mounts directly to a steel frame crossmember above the spare tire — the dissimilar-metal contact creates galvanic corrosion, accelerated by road salt and moisture. The aluminum case cracks, water shorts the internal circuit board, and the module stops driving the fuel pump. Symptoms: crank-no-start (most common), stalling after hitting a bump or stopping at lights, intermittent loss of power. Ford has not issued a safety recall for the F-150 FPDM, so repairs are at the owner's expense. Owners typically pay $150-$400 for module replacement plus relocation hardware that mounts the module away from the steel frame.
Common Symptoms
- Crank but no start
- Sudden stall while driving
- Loss of power
- Fuel pressure-related warning or code
- Intermittent starting problems
How to Fix
Inspect the fuel pump driver module and its mounting bracket for corrosion, cracking, or water intrusion, especially on rust-belt trucks. Repair usually involves replacing the FPDM and often the corroded mounting hardware or bracket, then confirming fuel pressure and wiring integrity; typical cost is about $150-$450. If the truck still will not start, test the fuel pump and rail pressure sensor circuit next.
Sources for this issue (1)
Gasoline F-350s of this era (5.4L Triton V8 and 6.8L Triton V10) use a Fuel Pump Driver Module bolted directly to the steel frame rail behind the rear axle, where it takes the full spray of road salt and water. The aluminum module against the steel frame sets up galvanic corrosion; the housing corrodes through, moisture reaches the circuit board, and the module stops driving the in-tank pump. The result is intermittent stalling, extended cranking or an outright no-start, often with FPDM circuit codes stored. Trucks in salt-belt states fail earliest. This is a chassis/electrical failure on the gas trucks only.
Common Symptoms
- Intermittent stalling
- Extended crank or no-start that comes and goes
- Loss of power under load
- Corroded module visible on the frame rail
How to Fix
Inspect the module on the frame rail for a swollen, cracked or white-corroded housing before condemning the in-tank pump. Replace the FPDM, and critically, clean the mounting surface and use dielectric grease on the connector; many owners relocate the module to a cleaner, drier surface or add a barrier between the module and the frame to break the galvanic path. Also inspect the pigtail for green corroded terminals, which will kill a new module. Separately, an erratic or stuck fuel gauge with a P0463 is a different problem, not an FPDM failure: it usually means the sender resistor card in the in-tank pump module, which is normally replaced complete. No recall covers the FPDM.
Sources for this issue (3)
P0191 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0191 mean on a Ford?
P0191 stands for "Fuel Rail Pressure Sensor Circuit Range/Performance." This code sets when the fuel rail pressure sensor's signal is out of its expected range or doesn't match what the computer expects for current conditions. On direct-injection and many modern engines, this sensor reports fuel pressure in the rail so the computer can precisely control fueling and the fuel pump. When the reading is implausible — too steady, erratic, or inconsistent with commanded pressure — this code is set, sometimes with hard starting, hesitation, or reduced power. It generally points to the sensor or its wiring, though an actual fuel-pressure problem can also trigger it. On Ford it is documented across 3 models: F-250 Super Duty, F-150, F-350.
What are the most common causes of P0191?
The most common causes of P0191 are: Faulty fuel rail pressure sensor, Corroded, loose, or damaged sensor connector, Open, shorted, or high-resistance sensor wiring, Actual fuel pressure out of range (weak pump or regulator), Restricted fuel filter or supply line, Loss of reference voltage or ground from the ECM/PCM, Faulty fuel pressure regulator or control valve. The specific cause varies by vehicle.
How much does it cost to fix P0191 on a Ford?
Published repair estimates on Ford range from $150 to $12,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.