P0087 on GMC: How to Diagnose & Fix
Fuel Rail/System Pressure - Too Low
5 GMC models · 5 documented issues · 5 critical · $350-$18,000 repair
P0087 on GMC by model: symptoms, diagnosis and fix
The Bosch CP4.2 high-pressure fuel injection pump used on the 2011-2016 LML (and LGH) Duramax diesel engines is prone to catastrophic failure that destroys the entire fuel injection system. Unlike its predecessor the CP3, the CP4.2 uses roller tappets riding on the cam that are lubricated only by the diesel fuel; when the fuel film is thin or the fuel is aerated, the rollers skid instead of rolling and the cam and tappet wear. When metal fatigue occurs, the pump shatters and sends metal debris throughout the entire high-pressure fuel system — contaminating all eight injectors, the fuel rails, return lines, and feed lines. Total repair cost runs $8,000-18,000. A class action lawsuit (Chapman v. General Motors) was filed against GM over 2011-2016 Silverado/Sierra HD Duramax trucks and was settled for owners who bought in seven states (CA, FL, IL, IA, NY, PA, TX). The same pump also fails in the Ford 6.7 Power Stroke (2011+) and the 2019-2020 Ram 6.7 Cummins.
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 the entire high-pressure fuel system: CP4 pump, all 8 injectors, both fuel rails, return lines, and flush the lift pump/FASS system. Install an aftermarket CP3 conversion kit (Fleece FPE-LML-CP3-WP for 2011-2016 LML) 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 (4)
The Sierra 3500HD Duramax LML diesel (2011-2016) 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 8 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 similar) is strongly recommended as a preventive upgrade on any high-mileage LML Sierra 3500HD. The 2017+ L5P switched to a Denso HP4 pump.
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 or S&S Diesel LML kit). Install FASS lift pump. Never run below 1/4 tank.
Sources for this issue (2)
The GMC Savana (and Chevrolet Express) fuel pump module is known for premature failure between 80,000-140,000 miles, often stranding drivers without warning. The in-tank electric fuel pump motor burns out or the sending unit becomes erratic. Running the tank consistently below 1/4 generates heat that shortens pump life. Commercial use Savanas that frequently run low on fuel — common in fleet operations — see pump failures well before 80,000 miles. The fuel pump is a demanding repair requiring tank removal on the Savana.
Common Symptoms
- Hard start or extended cranking before engine fires
- Engine stalls at idle and won't restart when hot
- Fuel pressure below specification (should be 55-60 psi)
- Engine stumbles and hesitates under load
- No-start condition with no fuel pressure
- Fuel gauge erratic or reads wrong
How to Fix
Replace fuel pump module (ACDelco MU1374 for 6.0L Savana, MU1373 for 4.8L). Keep fuel tank above 1/4 full at all times. For fleet vehicles, replace pump proactively at 100,000 miles. Aftermarket Walbro or Delphi pumps are common alternatives.
Sources for this issue (2)
NHTSA campaign 20V639 covers certain 2020 GMC Acadia vehicles. A plastic burr left in the fuel pump jet nozzle can block the nozzle and reduce fuel delivery to the engine, which can cause an engine stall.
Common Symptoms
- Insufficient fuel supply
- Possible engine stall
How to Fix
Check the VIN with GMC. Dealers replace the fuel-pump module free of charge under GM campaign N202314760.
Sources for this issue (1)
On 1.5L turbo Terrains, the in-tank fuel pump module may not consistently supply enough fuel because a tier-two supplier made an unauthorized production change that reduced pump clearances, starving the engine of fuel and causing sudden stalling and loss of power while driving - a crash risk. GM recall N222372310 (NHTSA 23V-013) covers 2022 Terrains built June 22, 2021 to February 1, 2022 (and 2021-2022 Equinox).
Common Symptoms
- Sudden engine stall while driving
- Loss of power/propulsion
- Hard starting or no-start
- Check engine light
- Rough running
How to Fix
Under recall, dealers replace the fuel pump module free of charge. Owners should verify their VIN against open recalls via NHTSA or a GMC dealer.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (2)
P0087 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 P0087 mean on a GMC?
P0087 stands for "Fuel Rail/System Pressure - Too Low." This code means the fuel rail or fuel system pressure has dropped below the level the engine's computer expects. The computer monitors a fuel pressure sensor and has seen pressure fall too low, meaning the engine isn't getting enough fuel — especially noticeable under acceleration or load. This is most common on direct-injection and diesel systems that run very high pressures. Symptoms include hard starting, stalling, hesitation, lack of power, and possible limp mode. On GMC it is documented across 5 models: Sierra 2500HD, Sierra 3500HD, Savana, Acadia, Terrain.
What are the most common causes of P0087?
The most common causes of P0087 are: Clogged or dirty fuel filter, Weak or failing fuel pump (lift pump or high-pressure pump), Faulty fuel pressure regulator or control valve, Restricted or leaking fuel lines, Faulty fuel pressure sensor, Air in the fuel system or running low on fuel, Worn high-pressure pump (direct injection/diesel). The specific cause varies by vehicle.
How much does it cost to fix P0087 on a GMC?
Published repair estimates on GMC range from $350 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.
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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.