P0087 on 2019 Acura ILX: Fuel Rail Pressure Too Low Causes and Fixes

What's Unique About the 2019-2019 Acura ILX

The 2019 Acura ILX is subject to a specific and widespread safety recall that directly causes the P0087 code. Acura issued Service Bulletin 21-012 because the impeller in the in-tank (low-pressure) fuel pump can swell due to a manufacturing defect, causing the pump to seize and stop working. This known defect is the most common reason for seeing this code on this specific vehicle, making it a critical, vehicle-specific issue rather than just a generic component failure. The recall was later expanded under NHTSA campaign 23V858000, covering a massive range of Honda and Acura vehicles.

Symptoms You May Notice

• Engine may stall while driving
• Engine will not start or has extended crank time
• Check Engine Light is on
• Multiple warning lights on the dashboard (often described as 'Christmas lights')
• Reduced engine power and acceleration (Limp Mode)
• Engine hesitation or sputtering, especially under load
• Rough idle

Most Likely Causes

1. Failing Low-Pressure Fuel Pump (In-Tank) 🔴 High Probability → Shop Fuel Pump A known manufacturing defect with the fuel pump impeller causes it to swell and seize. This was the subject of Acura Service Bulletin 21-012 and NHTSA Safety Recall 21V215000, which was later expanded. The bulletin explicitly states this failure will store DTC P0087. Acura Service Bulletin #B21-012 further notes that if the fuel pump motor impeller swells and seizes, the engine may not start or could stall while driving, increasing the risk of a crash.
   How to confirm: Check the vehicle's VIN with an Acura dealer or on the NHTSA website (www.nhtsa.gov) for recall eligibility for campaigns 21V215000, 20V-314, or the expansion 23V858000. If not covered or already performed, a technician will test the low-pressure fuel system's output pressure to see if it meets specifications. Expected pressure is approximately 50-70 PSI at idle.
   Typical fix: Replace the in-tank fuel pump motor/module. If the vehicle is eligible for the recall, this repair will be performed by an Acura dealer at no cost. The recall kit part number is 06170-TV9-305.
   Est. part cost: $0 (if recall applies) | $250-$450 (if not)
2. Failing High-Pressure Fuel Pump (HPFP) 🟡 Medium Probability → Shop Fuel Pump The HPFP is a common failure point for P0087 on many direct-injection engines once the low-pressure side is confirmed to be working correctly. A technician on YouTube noted this is a common issue on the 2.4L TLX, a platform mate. Honda also issued a TSB (14-071) for failing HPFPs on the related 2.4L Accord, indicating a potential weakness in the part design. 🎬 See this walkthrough for replacing the high-pressure fuel pump
   How to confirm: Using a scan tool with live data (like the Acura i-HDS), a technician will monitor the desired vs. actual fuel rail pressure. One technician noted that on a failed pump, the actual pressure was only 250 kPa when the desired was 10,000 kPa. If the low-pressure pump is supplying adequate volume but the high-pressure rail does not reach its target, the HPFP is suspect.
   Typical fix: Replace the high-pressure fuel pump located on the engine. This requires setting the engine to Top Dead Center (TDC) for cylinder 1 to ensure the pump's cam lobe is in the correct position for removal.
   Est. part cost: $300-$600
3. Clogged Fuel Filter ⚪ Low Probability → Shop Fuel Filter The fuel filter is integrated into the in-tank fuel pump module. While it can clog and restrict flow, it's far more likely that the entire pump module fails due to the recall issue before the filter becomes the sole point of failure.
   How to confirm: This is typically diagnosed by measuring low fuel pressure from the tank. If pressure is low, the entire pump and filter assembly is usually replaced as a single unit.
   Typical fix: Replace the fuel filter set, which is part of the in-tank fuel pump module.
   Est. part cost: $40-$80

Rare But Worth Checking

• Faulty Fuel Rail Pressure Sensor: → Shop Fuel Pressure Sensor The sensor itself can fail and send an incorrect low-pressure reading to the ECM, even if the pressure is actually fine. This can be checked by comparing the sensor's reading to a manual pressure gauge or observing erratic readings on a scan tool. The sensor is located on the fuel rail.
• Leaking Fuel Injector: → Shop Fuel Injector A direct injector that is stuck open can bleed off pressure from the fuel rail, causing the system pressure to drop and trigger P0087. This would likely be accompanied by misfire codes for a specific cylinder.
• Worn HPFP Cam Follower/Roller: → Shop Fuel Pump The high-pressure fuel pump is driven by a lobe on the camshaft. The roller or follower that rides on this cam can wear down, preventing the pump from achieving its full stroke and generating adequate pressure. Service procedures recommend inspecting the roller and camshaft for wear whenever the HPFP is replaced.

Diagnosis Steps

1. Check for Recalls: Immediately contact an Acura dealership or use your VIN on the NHTSA website (www.nhtsa.gov) to check for eligibility for Safety Recalls 21V215000, 20V-314, and the expanded campaign 23V858000 regarding the fuel pump motor. If eligible, have the recall service performed by a dealer. This is the most critical first step.
2. Scan for Codes: Read all stored fault codes with an OBD-II scanner to confirm P0087 and check for any other related codes, such as misfires (P030x) or sensor performance (P0191).
3. Analyze Live Data: Use a scan tool to monitor live fuel system data. Compare the 'Desired Fuel Rail Pressure' with the 'Actual Fuel Rail Pressure'. A significant and consistent discrepancy where actual is much lower than desired 🎬 Watch: How to diagnose and fix low fuel rail pressure confirms a real pressure problem. Manufacturer Bulletin #BTI&03282023902 notes that Acura has investigated similar complaints where P0087 is stored alongside conditions like the engine being hard to start.
4. Test Low-Pressure System: If the recall does not apply or has already been performed, test the pressure of the in-tank (low-pressure) fuel pump. It must meet OEM specifications (approx. 50-70 PSI) to properly feed the high-pressure pump.
5. Inspect High-Pressure System: If the low-pressure side is healthy, the focus shifts to the high-pressure system. Visually inspect the high-pressure fuel pump (HPFP) for any leaks. Using a scan tool, command the HPFP and observe if the rail pressure responds accordingly.
6. Test Fuel Rail Pressure Sensor: → Shop Fuel Pressure Sensor Check the fuel rail pressure sensor's output. If the readings are erratic, do not change with engine RPM, or do not match a manual pressure gauge reading (if a test port is available), the sensor may be faulty.
7. Inspect for Leaks: Check for any external or internal fuel leaks. This includes fuel lines, injector seals, and stuck-open injectors that could bleed off rail pressure.

Parts You'll Likely Need

• Fuel Pump Motor Kit (In-Tank) (OEM #06170-TV9-305) — This is the specific part kit identified in Acura's safety recall 21-012 for the 2019 ILX, making it the most probable cause of code P0087.
  Trusted brands: Acura (OEM)
  OEM price range: $0 (Recall) | $250-$400
  Aftermarket price range: N/A (Use OEM for recall)
• Fuel Pump Module Assembly (In-Tank) (OEM #17045-TV9-A01) — If the vehicle is not under recall or the owner opts to replace the entire assembly instead of just the motor, this is the complete unit.
  Trusted brands: Acura (OEM)
  OEM price range: $400-$580
  Aftermarket price range: $150-$300
• High-Pressure Fuel Pump (OEM #16790-5LA-A01) — If the low-pressure pump is working correctly, the engine-mounted high-pressure pump is the next most likely component to fail and cause low rail pressure.
  Trusted brands: Acura (OEM), Delphi, Standard Motor Products
  OEM price range: $590-$850
  Aftermarket price range: $250-$650
• Fuel Filter Set (OEM #17048-TR0-L10) — A clogged fuel filter can restrict fuel flow, though it is less common than outright pump failure. It is often replaced with the in-tank fuel pump.
  Trusted brands: Acura (OEM)
  OEM price range: $40-$80
  Aftermarket price range: $20-$50

Related Codes That Often Appear With This One

• P0300-P0304 — Low fuel pressure can lead to a lean air-fuel mixture, causing random or specific cylinder misfires.
• P0191 — This code for 'Fuel Rail Pressure Sensor Circuit Range/Performance' can sometimes appear alongside P0087, indicating a problem with the sensor's readings that could be caused by either the sensor itself or actual pressure issues.

Technical Service Bulletins (TSBs) & Recalls

• Acura Service Bulletin 21-012: 'Safety Recall: 2019 ILX Fuel Pump Motor' - Describes the defect in the low-pressure fuel pump that causes it to seize, store DTC P0087, and potentially stall the engine. Provides the corrective action to replace the fuel pump motor.
• Acura Service Bulletin 21-016: 'Safety Recall: Multi-Model Fuel Pump Motor' - A placeholder and broader bulletin that also identifies the swelling impeller issue and P0087 code across multiple Acura models including the ILX, RDX, MDX, and TLX.
• Acura Service Bulletin #B21-012: Notes that due to swelling of the fuel pump motor impeller, the fuel pump may seize and stop working, resulting in DTC P0087 and potential engine stalling.
• Manufacturer Bulletin #BTI&03282023902: Indicates an investigation into P0087 and hard-to-start conditions on other Acura models like the MDX and RDX.

Platform-Specific Known Issues

• Safety Recall 21-012 / NHTSA 21V215000: The primary issue for this vehicle. The in-tank fuel pump motor impeller can swell, causing the fuel pump to seize. This leads to a loss of fuel pressure, triggering code P0087 and potentially causing the engine to stall while driving.

Mechanic-Grade Diagnostic Values

• Low-Pressure Fuel System Pressure (at idle) — expected: Approximately 50-70 PSI. Failure: Pressure significantly below 50 PSI, or zero pressure, indicates a failed in-tank pump or severe restriction.
• High-Pressure Fuel System Commanded vs. Actual Pressure (Live Data) — expected: Actual pressure should closely track commanded pressure. Commanded pressure can be 500-600 PSI at idle and exceed 2,000-3,000 PSI under load.. Failure: Actual pressure is significantly lower than commanded pressure. One technician noted an actual reading of only 250 kPa (~36 PSI) when 10,000 kPa (~1450 PSI) was commanded, indicating a failed HPFP.
• Fuel Rail Pressure Sensor Voltage (Key-On) — expected: Typically 0.5V at low/atmospheric pressure and rises towards 4.5V at maximum pressure.. Failure: Voltage is stuck low, high, or does not change with pressure, indicating a faulty sensor or wiring issue.

Scan Tool Commands That Help

• Acura i-HDS (Honda Diagnostic System): FUEL PUMP OFF (in PGM-FI Function Test menu) — This command is used to safely relieve fuel system pressure before servicing high-pressure components like the HPFP or fuel rail. The technician runs this function, then starts the engine and lets it stall from fuel starvation.
• Acura i-HDS (Honda Diagnostic System): FUEL RAIL PRESSURE TEST (in Inspection Menu) — This is a guided diagnostic test to verify fuel pressure readings and check the overall status of the fuel system after a repair, such as replacing a pump or sensor, to confirm the fix was successful.
• Advanced Bi-Directional Scan Tool (e.g., Autel, XTOOL): Fuel Pump Relay Activation — Allows a technician to command the low-pressure fuel pump on and off directly. This is used to test the integrity of the relay, wiring, and the pump motor itself without having to crank the engine, helping to isolate a failure in the low-pressure circuit.

Wiring & Ground Locations

• Fuel Pump Control Module — On many modern Hondas/Acuras, the fuel pump is controlled directly by the PCM or via a dedicated relay, rather than a separate external module. The primary electrical components to check are the PGM-FI Main Relay 2 in the under-dash fuse box and the connector at the fuel tank access panel under the rear seat.. A failure in the relay or a problem with the wiring/connector to the in-tank pump will cut power, causing zero fuel pressure and triggering P0087.
• Fuel Pump Ground — The fuel pump assembly grounds to the chassis, typically via a ground splice pack located under the rear seat or in the trunk area.. A corroded or loose ground connection for the fuel pump can cause intermittent or total loss of pump operation, leading to low fuel pressure symptoms.

Real Owner Repair Stories

• Reddit user DWC66 (2016 Acura MDX (shares direct injection architecture)) — Car stalled, would not restart initially, then started but idled rough with surging and intermittent power loss. Multiple system warnings on the dash. Code P0087 was stored and came right back after clearing.
  ❌ Tried (didn't work) Checked battery voltage (was normal), Reset computer by disconnecting battery, Replaced the fuel pump relay
  ✅ What actually fixed it The high-pressure fuel pump (HPFP) was diagnosed as the fault and was replaced, which resolved all symptoms.
• YouTube channel "nutsandboltsauto" (2014 Honda Accord 2.4L (engine platform relative)) — Stored P0087 code.
  ❌ Tried (didn't work) The video focuses directly on the TSB-indicated repair, bypassing other diagnostics based on the bulletin.
  ✅ What actually fixed it Following Honda TSB 14-071, the high-pressure fuel pump was replaced. The video notes this is a very common failure for P0087 on this engine.
• NHTSA ODI #11613363 — An owner reported experiencing a loss of power at 60 mph on the highway. Despite replacing the high-pressure fuel pump for a P0087 code, the vehicle continued to exhibit the same issues, leading the owner to identify a recall for the problem.
• NHTSA ODI #11460123 — An owner reported that their vehicle stalled while driving and was unable to restart immediately; an independent mechanic diagnosed the issue as code P0087 for the fuel rail system.
• NHTSA ODI #11673469 — A report describes a fuel pump malfunction with DTC P0087 and P2636, which the owner noted was identical to the defect described under Recall 23V-858.

OEM Part Supersession History

• 16790-5A2-A01 → 16790-5LA-305, which was then superseded by 16790-5LA-A01 — Part revisions to improve reliability and address failure patterns leading to codes like P0087.
  Heads up: While all three part numbers may be listed by vendors for the K24W engine series, it is critical to use the latest revision (16790-5LA-A01) for the 2019 ILX to ensure compatibility and benefit from the design improvements.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Driveshaft Separation 🔴 High — Affects 2016-2019 models. Significant enough to warrant a safety recall. (Ref: NHTSA Recall 19V402000: Excessive grease on the half shaft set-ring may prevent full engagement, allowing the driveshaft to separate, causing a loss of drive or vehicle roll-away in Park.)
• Inaccurate Fuel Gauge 🟠 Medium — Affects 2014-2019 models. A deformed fuel tank can cause the fuel level float to stick. (Ref: NHTSA Recall 19V062000: The fuel gauge may show more fuel than is actually in the tank, leading to the vehicle running out of gas unexpectedly and stalling.)
• Brake Master Cylinder Failure 🔴 High — Affects 2016-2020 models. A recall was issued for this potential failure. (Ref: NHTSA Recall 24V064000: Contaminated brake fluid can cause a seal in the master cylinder to deform, leading to an internal fluid leak and reduced braking performance.)
• Knocking or Clicking From Engine During Cold Startup 🟠 Medium — Reported on 2016-2018 models, but relevant to the platform. (Ref: Acura TSB 19-012: Addresses a knocking or clicking noise from the VTC actuator on cold starts. While not for the 2019 model specifically, it's a known K-series engine issue.)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: For this specific code on this vehicle, using used parts is highly discouraged. A used low-pressure pump carries the same defect risk that prompted the recall. A used high-pressure pump (HPFP) could be considered a budget option ONLY if from a very low-mileage, verified-running donor vehicle, but the labor cost makes a new part a much smarter investment.

Donor-vehicle mileage cap: roughly under 40000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a used HPFP, inspect the cam follower roller for any signs of scoring or wear.
• Ensure all electrical connectors are clean, dry, and free of corrosion.
• Check the part number to ensure it's the latest revision if possible.
• Avoid any parts from vehicles that show signs of sitting for a long time (e.g., heavy rust, water damage).

OEM-only on this vehicle (don't cheap out):

• Low-Pressure Fuel Pump (In-Tank): Due to the safety recall, only a new OEM part (or the free recall replacement) should be used to guarantee the impeller defect is resolved.
• High-Pressure Fuel Pump (HPFP): This is a precision, high-stress component critical to engine operation. While some aftermarket options exist, OEM is strongly recommended for longevity and to avoid repeat failures.

Aftermarket brands forum-validated for this vehicle:

• For the HPFP, Delphi is a reputable OEM supplier for many manufacturers and can be a reliable alternative to the Acura-branded part.

Brands owners have reported issues with on this vehicle:

• Avoid unbranded, no-name parts from online marketplaces for both the low-pressure and high-pressure fuel pumps. The failure risk is too high for such a critical system.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0191 — Fuel Rail Pressure Sensor Circuit Range/Performance; often checked alongside P0087 to determine if the sensor itself is faulty or if the pressure is actually low.
• P030X — Misfire codes (P0300-P0304) may trigger because the lack of fuel pressure caused by a failing pump leads to a lean condition and combustion failure.
• P0088 — Fuel Rail Pressure Too High; the opposite of P0087, often involving the same high-pressure fuel pump or rail sensor diagnostic steps.

Frequently Asked Questions