P0190 on GMC: How to Diagnose & Fix
Fuel Rail Pressure Sensor Circuit Malfunction
2 GMC models · 2 documented issues · 2 critical · $8,000-$18,000 repair
P0190 on GMC by model: symptoms, diagnosis and fix
The Bosch CP4.2 high-pressure fuel injection pump used on the 2011-2016 LML and 2017-2020 L5P Duramax diesel engines is prone to catastrophic failure that destroys the entire fuel injection system. Unlike its predecessor the CP3, the CP4.2 lacks a roller element and relies solely on fuel for lubrication. When metal fatigue occurs, the pump shatters and sends metal debris throughout the entire high-pressure fuel system — contaminating all six injectors, the fuel rails, return lines, and feed lines. Total repair cost runs $8,000-18,000. A class action lawsuit was filed against GM. The same pump also fails in Ford 6.7 Power Stroke and Ram 6.7 Cummins of the same era.
Common Symptoms
- Hard start or no-start condition
- Sudden loss of power under load
- Rough running or misfiring on multiple cylinders
- Metal shavings or debris visible in fuel filter
- Fuel rail pressure codes (P0087, P0191)
- White or black smoke from exhaust
- DIC message: Reduced Engine Power
How to Fix
Replace entire high-pressure fuel system: CP4 pump, all 6 injectors, both fuel rails, return lines, and flush the lift pump/FASS system. Install aftermarket CP3 conversion kit (Fleece FPE-CP3K-LML or FPE-CP3K-L5P) to replace the CP4.2 with the more durable CP3 design. Add a FASS or AirDog lift pump to improve fuel supply. Prevention: never run below 1/4 tank, use quality diesel fuel.
Sources for this issue (1)
The Sierra 3500HD Duramax diesel uses the same Bosch CP4.2 high-pressure fuel pump as the 2500HD. The pump is prone to catastrophic failure that destroys the entire fuel injection system (all 6 injectors, fuel rails, return lines). The 3500HD is often used for heavier towing and work applications, which places more sustained load on the high-pressure fuel system and may accelerate CP4.2 wear. Total system replacement costs $10,000-18,000. A CP3 conversion kit (Fleece FPE-CP3K-LML or FPE-CP3K-L5P) is strongly recommended as a preventive upgrade on any high-mileage Sierra 3500HD Duramax.
Common Symptoms
- Sudden hard start or no-start
- Loss of power under towing load
- Rough running on multiple cylinders
- Metal shavings in fuel filter
- Fuel rail pressure codes P0087, P0191
- Reduced Engine Power message
How to Fix
Replace entire fuel system on failure. Preventive CP3 conversion kit (Fleece FPE-CP3K-LML for LML, FPE-CP3K-L5P for L5P). Install FASS lift pump. Never run below 1/4 tank.
Sources for this issue (1)
P0190 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 P0190 mean on a GMC?
P0190 stands for "Fuel Rail Pressure Sensor Circuit Malfunction." P0190 indicates a malfunction in the fuel rail pressure sensor circuit. This sensor measures the pressure of fuel in the rail (common on direct-injection and high-pressure systems) and reports it to the PCM, which uses it to control the fuel pump and injectors for precise fueling. The code sets when the sensor's signal is out of range, erratic, or electrically faulty. Symptoms can include hard starting, stalling, hesitation, reduced power, or the engine going into a reduced-power fail-safe mode. On GMC it is documented across 2 models: Sierra 2500HD, Sierra 3500HD.
What are the most common causes of P0190?
The most common causes of P0190 are: Faulty fuel rail pressure sensor, Damaged wiring or connector at the sensor, Corroded or loose connector terminals, Open, short, or poor ground in the sensor circuit, Reference voltage problem from the PCM, Actual fuel pressure problems (pump/regulator) confusing the sensor, Failed PCM input (rare). The specific cause varies by vehicle.
How much does it cost to fix P0190 on a GMC?
Published repair estimates on GMC range from $8,000 to $18,000 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.
Looking for P0190 on a different make?
View P0190 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.