P0087 on 2019-2022 Acura RDX: Fuel Rail Pressure Too Low Causes and Fixes

What's Unique About the 2019-2022 Acura RDX

This generation of Acura RDX is known for a specific fuel system vulnerability. The low-pressure fuel pump, located in the fuel tank, is prone to failure due to a defective impeller that can swell from fuel absorption and seize. This issue was so widespread on 2019-2020 models that it prompted a major safety recall (NHTSA Campaign 21V215000 🎬 Watch: Overview of the 2019 RDX fuel pump recall) and several manufacturer TSBs, making the in-tank fuel pump the primary suspect for code P0087. Furthermore, TSB BTI&03282023902 shows that Honda began investigating this same code on 2020-2022 models, suggesting the problem may persist beyond the initial recall dates.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Multiple warning lights illuminated on the dash.
• Engine may not start.
• Engine stalls while driving.
• Engine is hard to start or has an extended crank.
• Reduced engine power and acceleration ('limp mode').
• Engine hesitation, stumbling, or misfiring.
• Engine runs rough or shakes.

Most Likely Causes

1. Failing Low-Pressure Fuel Pump (In-Tank) 🔴 High Probability Acura issued recall 21V215000 and TSB B21-014 for 2019-2020 RDX models because the fuel pump impeller was made of a low-density material that could absorb fuel, swell, and cause the pump to seize. This manufacturing defect is the most documented cause of P0087 on this platform. Some owners of vehicles not included in the recall have also reported identical failures.
   How to confirm: First, check the vehicle's VIN for open recalls on the NHTSA or Acura recall website. A technician can perform a low-pressure fuel system test by connecting a gauge to the low-pressure line; the target pressure is around 70 PSI. If pressure is low or non-existent, the pump has failed.
   Typical fix: Replace the in-tank fuel pump module. If the vehicle is under the recall, this repair will be performed by an Acura dealer free of charge. The access panel is located under the rear seat cushion. 🎬 See this walkthrough for replacing the in-tank fuel pump
   Est. part cost: $0 (if under recall), $250-$450 (aftermarket)
2. Failing High-Pressure Fuel Pump (HPFP) 🟡 Medium Probability While less common than the low-pressure pump recall, the engine-mounted high-pressure pump can also fail and cause P0087. TSB B21-014 explicitly states that other repairs, like replacing the HPFP, should only be attempted after the low-pressure pump recall work is done and the issue persists. Some owners have reported needing an HPFP replacement even on post-recall vehicles.
   How to confirm: A technician can use a scan tool to monitor desired vs. actual fuel rail pressure on the high-pressure side. A significant discrepancy where actual pressure is far below desired pressure points to an issue with the HPFP. One technician noted a reading of 250 kPa when the target was 10,000 kPa, indicating a failed HPFP.
   Typical fix: Replace the high-pressure fuel pump. This pump is driven by the camshaft, and its replacement may also require replacing a fuel joint pipe.
   Est. part cost: $400-$800
3. Clogged Fuel Filter ⚪ Low Probability The fuel filter is integrated into the low-pressure fuel pump assembly in the tank. If it becomes clogged with debris, it can restrict fuel flow and cause low pressure. This is less common than outright pump failure on this model but is still a possibility, especially on higher-mileage vehicles or those that have used poor-quality fuel.
   How to confirm: Diagnosis typically involves a fuel pressure test. If pressure is low and the pump is known to be good (or new), a restriction is suspected. The filter is usually inspected upon removal of the fuel pump assembly.
   Typical fix: Replace the fuel pump assembly, as the filter is typically not sold separately from the module.
   Est. part cost: $300-$600
4. Failed Fuel Pressure Sensor ⚪ Low Probability
   How to confirm: A technician can compare the fuel pressure reading from the scan tool with a reading from a mechanical fuel pressure gauge. If the readings do not match, the sensor is likely faulty. This is an uncommon failure point compared to the pumps themselves.
   Typical fix: Replace the fuel rail pressure sensor.
   Est. part cost: $50-$150

Rare But Worth Checking

• Leaking Fuel Injector: A fuel injector stuck open can cause a drop in rail pressure. This would likely be accompanied by other symptoms like a rich running condition, black smoke from the exhaust, or a strong smell of fuel.
• Damaged Fuel Line: A kinked, pinched, or leaking fuel line between the tank and the engine can restrict flow and cause a pressure drop. This is unlikely without prior physical damage to the underbody of the vehicle.
• Worn Camshaft Lobe: The high-pressure fuel pump is mechanically driven by a lobe on the camshaft. In rare cases, wear on this lobe or the pump's roller follower can reduce the pump's stroke, leading to insufficient pressure. This should be inspected when replacing the HPFP.

Diagnosis Steps

1. Check the vehicle's VIN for open recalls, specifically NHTSA campaign 21V215000, on the Acura or NHTSA websites.
2. If a recall is active, contact an Acura dealership to have the repair performed free of charge.
3. If no recall is active, use an OBD-II scanner to confirm P0087 is the primary code and check for any other DTCs.
4. Use a scan tool with live data to monitor both low-pressure and high-pressure fuel system desired vs. actual pressures.
5. Perform a low-pressure fuel system test to check the health of the in-tank fuel pump. A healthy pump should produce around 70 PSI.
6. If the low-pressure system is healthy, test the high-pressure fuel pump's performance using the scan tool's live data during cranking and idling.
7. Inspect for any visible fuel leaks along the fuel lines from the tank to the engine, paying attention to the connections at both pumps.
8. If the HPFP is replaced, inspect the camshaft lobe and roller follower for wear.

Parts You'll Likely Need

• Fuel Pump Module Assembly (Low Pressure) (OEM #17045-TJB-A04 (replaces 17045-TJB-A03)) — This is the most common failure point for this code on this vehicle, as documented by a major recall and multiple TSBs.
  Trusted brands: Acura OE, Denso (951-0007), Delphi (FG2695)
  OEM price range: $265-$400
  Aftermarket price range: $250-$450
• High-Pressure Fuel Pump (OEM #16790-6B2-A01) — This is the second most likely pump to fail, but should only be considered after the low-pressure pump has been ruled out or replaced.
  Trusted brands: Acura OE, Bosch
  OEM price range: $370-$540
  Aftermarket price range: $400-$600

Related Codes That Often Appear With This One

• U047168ECM — This code was reported alongside P0087 in an owner complaint (ODI #11545649) and may relate to communication errors resulting from the fuel system failure.

Technical Service Bulletins (TSBs) & Recalls

• B21-014: Safety Recall: 2019-20 RDX Fuel Pump Motor. Details the cause (swelling impeller) and corrective action (replace fuel pump) for P0087.
• BTI&03282023902: An internal request for dealership technicians to report instances of P0087 on 2020-2022 MDX & RDX models for further investigation, particularly when accompanied by hard start or no-start symptoms.

Platform-Specific Known Issues

• NHTSA Recall 21V215000 was issued for 2019-2020 RDX models due to a low-pressure fuel pump impeller that could swell and cause the pump to fail, leading to engine stalling.
• TSB #B21-014 provides the diagnostic and repair procedure for the recalled fuel pump, explicitly linking the failure to DTC P0087.
• TSB #BTI&03282023902 indicates that American Honda was actively investigating P0087 on 2020-2022 RDX and MDX models as of March 2023, suggesting the issue may extend beyond the initial recall scope or involve other components.
• Some owners have reported issues even after the recall repair, including loud, high-pitched noises from the new pump and subsequent stalling, leading to a second replacement.

Mechanic-Grade Diagnostic Values

• High-Pressure Fuel Rail Pressure (Actual vs. Desired) — expected: At idle, desired and actual pressure should be closely matched. One technician reported a target of 10,000 kPa.. Failure: A significant drop in actual pressure compared to the desired value. One case showed an actual pressure of only 250 kPa when 10,000 kPa was commanded, indicating a failed High-Pressure Fuel Pump (HPFP).

Scan Tool Commands That Help

• Acura i-HDS (Honda Diagnostic System): FUEL PUMP OFF — This function is used in the PGM-FI system menu to safely relieve fuel pressure before servicing fuel system components like the fuel pump or fuel lines. The command shuts off the pump, allowing the technician to run the engine until it stalls from fuel starvation.

Wiring & Ground Locations

• Fuse #21 (Passenger Compartment Fuse Box) — Located in the fuse box under the driver's side dashboard.. This 20A fuse is designated for the FUEL PUMP. If this fuse is blown, the low-pressure fuel pump will not receive power, leading directly to a P0087 code and a no-start or stalling condition.

Real Owner Repair Stories

• Reddit user in r/Acura (2016 Acura MDX (shares direct injection architecture with RDX)) — Car began to stall, threw multiple system warnings (lane assist, power steering, etc.), idled rough, had intermittent power loss, and would not restart immediately. The only stored code was P0087.
  ❌ Tried (didn't work) Resetting the code (it came right back), Checking battery voltage, Disconnecting the battery, Replacing the fuel pump relay
  ✅ What actually fixed it The user later confirmed that replacing the high-pressure fuel pump resolved all the issues.
• Reddit user in r/Acura (Unknown year RDX/MDX) — Multiple malfunction lights on the dash, vehicle would not exceed 45 MPH, engine would rumble and shake, and experienced long cranks when starting.
  ❌ Tried (didn't work) Initial inspection of fuel quality found no issues.
  ✅ What actually fixed it A technician confirmed DTC P0087, found abnormalities with the high-pressure fuel pump, and replaced it along with the spark plugs. The user reported the car was running fine after the repair.

OEM Part Supersession History

• 17045-TJB-A02, 17045-TJB-A03 → 17045-TJB-A04 — These part numbers represent revisions to the low-pressure fuel pump module assembly. The changes are likely related to addressing the impeller swelling defect identified in the recall.
  Heads up: The latest part number, 17045-TJB-A04, should be used for all replacements to ensure the most updated component is installed.

Model Year Variations Within This Range

• 2022: The 2022 model year received a refresh. While the 2.0L Turbo engine and 10-speed transmission remained the same, Acura re-tuned the adaptive suspension and made engineering changes to reduce cabin noise. Wireless Apple CarPlay/Android Auto also became standard. These changes do not directly affect the cause of P0087 but distinguish the model year.
• 2019-2020: These model years were the primary focus of the NHTSA safety recall 21V215000 for the defective low-pressure fuel pump. While later years are also under investigation per TSB BTI&03282023902, the 2019-2020 models have the highest documented failure rate for this specific part.