P0430 on 2019-2025 Honda Pilot: Catalyst Efficiency Bank 2 Causes & Fixes

What's Unique About the 2019-2025 Honda PILOT

While P0430 commonly means a failed catalytic converter on many vehicles, on the 2019-2025 Honda Pilot and its platform mates, there is a very high probability that the root cause is faulty fuel injectors. Honda's own Technical Service Bulletins (TSBs), like 19-072 and 20-100, explicitly state that the PCM software may misinterpret sensor inputs and that debris from the manufacturing process can cause injectors to clog or wear, leading to a rich condition. This triggers the P0430 code, often accompanied by P219B (Air-Fuel Ratio Imbalance). This known issue has led to an extended warranty (10 years/150,000 miles) for the fuel injectors on many of these vehicles, making it critical to check with a dealer before paying for repairs.

Diagnostic Flowchart

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

Generation note: This range covers two Pilot generations: the end of the third generation (2019-2022, J35Y6 engine) and the start of the fourth generation (2023-2025, J35Y8 DOHC engine). The fuel injector issue is well-documented for the 2019-2022 models in TSBs. A TSB for the 2025 model also mentions collecting parts for P0430, indicating the issue may persist or is being monitored on the newer J35Y8 engine.

Symptoms You May Notice

• Check Engine Light is on
• Vehicle may fail an emissions test
• Potential for reduced fuel economy
• Possible rough idle or hesitation if the cause is a severe misfire or fuel issue
• A 'strange noise' from the engine was noted in one owner complaint.
• In some cases, a smell of raw fuel may be noticeable near the exhaust.

Most Likely Causes

1. Faulty Fuel Injectors 🔴 High Probability This is the most common cause. TSBs 19-072 and 20-100 confirm that debris from the high-pressure fuel pump or the injector machining process can cause internal wear or clogging. This leads to a rich fuel mixture (too much fuel) or misfires that overwhelm and trigger the catalyst efficiency code. Numerous NHTSA complaints corroborate this exact failure pattern.
   How to confirm: Check long-term fuel trims for Bank 2; a significant negative number (e.g., -10% or more) indicates a rich condition. The definitive dealer test is the 'Cylinder AF Test' using a Honda HDS scan tool. 🎬 Watch: How to diagnose these codes using Service Bulletin 20-100. A failed test confirms the need for injector replacement.
   Typical fix: Replace the set of all six fuel injectors and the fuel joint pipe. A PCM software update is also required per Honda's service bulletins. Check with a dealer about eligibility for the extended warranty (10yr/150k miles) before paying for the repair.
   Est. part cost: $400-$800 for a set of OEM injectors. The OEM part number for the set of 6 has been updated; a common replacement part number is 16010-RLV-315, which supersedes 16010-RLV-305.
2. Failed Catalytic Converter 🟡 Medium Probability The converter can fail from age, but it's often damaged as a *consequence* of an underlying issue like faulty fuel injectors dumping raw fuel into the exhaust. One owner reported replacing the converters only to have a related fuel code (P219B) appear later, suggesting the root cause wasn't fixed.
   How to confirm: Graph the upstream and downstream O2 sensor data on a warm engine. The downstream sensor (Sensor 2) voltage should be steady and high (typically >0.6V). If it mirrors the rapid up-and-down switching of the upstream sensor (Sensor 1), the converter is not storing oxygen and has failed. An infrared thermometer can also be used; the outlet should be significantly hotter than the inlet.
   Typical fix: Replace the Bank 2 catalytic converter (front, radiator side). It is critical to fix the root cause (e.g., bad injectors) first, or the new converter will fail quickly. The OEM part is often integrated with the exhaust manifold. 🎬 Watch: How to diagnose and replace the catalytic converter.
   Est. part cost: $1500-$2500 for an OEM converter. An example OEM part number for 2019-2022 models is 18180-RLV-A00.
3. Failing Oxygen (O2) Sensor ⚪ Low Probability A lazy or biased downstream (Bank 2, Sensor 2) O2 sensor can send false data to the PCM, making a good converter look bad. An owner complaint mentions P0430 appearing with an O2 sensor code (P219B), but this combination more strongly points to the injector issue described in TSBs.
   How to confirm: The sensor's voltage should be steady between 0.6V and 0.8V on a warm, running engine at steady RPM. If it's stuck low (near 0.1V) or high (near 0.9V), or fluctuating wildly like the upstream sensor, it's likely faulty. This test should only be trusted after confirming fuel trims are normal. The heater circuit resistance should be between 10 and 40 ohms.
   Typical fix: Replace the Bank 2, Sensor 2 (downstream) oxygen sensor.
   Est. part cost: $80-$200
4. Exhaust Leak ⚪ Low Probability
   How to confirm: Visually inspect the exhaust manifold, gaskets, and pipes between the engine and the catalytic converter for cracks or black soot trails. A smoke machine test is the most effective way to find small leaks that can draw in oxygen and fool the sensors.
   Typical fix: Replace the leaking gasket or repair/replace the cracked component.
   Est. part cost: $20-$150

Diagnosis Steps

1. Check for TSBs and Warranty Extension: Before any diagnosis, contact a Honda dealer with your VIN. Ask them to check for eligibility under the warranty extension for fuel injectors related to TSBs 19-072 and 20-100. This could result in a free repair.
2. Scan for All Codes: Use an OBD-II scanner to check for any other codes. The presence of P219B, P219A, or P030x codes alongside P0430 strongly points towards the fuel injector issue described in the TSBs.
3. Analyze Fuel Trims: Check the Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT) for Bank 2. A significantly negative LTFT (e.g., below -10%) indicates the PCM is reducing fuel to compensate for a rich condition, a classic symptom of a leaking or faulty injector.
4. Perform Cylinder AF Test: If you have access to a high-level scan tool like the Honda HDS, run the 'Cylinder AF Test'. This is the specific test Honda technicians use to confirm injector failure as outlined in the TSBs.
5. Test Oxygen Sensors: If fuel trims are normal, graph the voltage of the Bank 2 upstream (Sensor 1) and downstream (Sensor 2) O2 sensors. The upstream sensor should fluctuate rapidly. The downstream sensor should show a relatively steady, high voltage (above 0.6V). If the downstream sensor's graph mirrors the upstream sensor, the catalytic converter is not functioning.
6. Inspect for Exhaust Leaks: Visually and audibly inspect the exhaust system from the engine to the catalytic converter for any signs of leaks, such as black soot, cracks, or audible hissing/ticking sounds, especially when the engine is cold.
7. Verify Catalytic Converter Failure: Only after definitively ruling out injectors (the #1 cause), O2 sensors, and exhaust leaks should you conclude the catalytic converter has failed.

Parts You'll Likely Need

• Fuel Injector Set (OEM #16010-RLV-315 (Supersedes 16010-RLV-305)) — This is the most likely root cause of P0430 on this specific vehicle, as documented by owner complaints and Honda TSBs. Replacement as a full set of six is recommended. 🎬 See this walkthrough for replacing the GDI fuel injectors.
  Trusted brands: Honda Genuine Parts
  OEM price range: $240-$350 for the set online.

Related Codes That Often Appear With This One

• P219B — Air-Fuel Ratio Imbalance (Bank 2). This code is the smoking gun. It is frequently seen with P0430 and is explicitly mentioned in Honda's TSBs as being caused by faulty injectors. If you have P0430 and P219B, the injectors are the primary suspect.
• P0300-P0306 — Random or specific cylinder misfire codes (e.g., P0304 for cylinder 4). An owner complaint directly links these with P0430 and failed injectors. Misfires allow unburned fuel to enter the exhaust, which can damage the catalytic converter and trigger efficiency codes. The TSBs also cover this combination.
• P0420 — Catalyst System Efficiency Below Threshold (Bank 1). While P0430 is for Bank 2, seeing P0420 at the same time indicates the problem is affecting both engine banks. This could point to a systemic issue like contaminated fuel or, more likely on this platform, that injectors on both banks are failing. The TSBs cover both codes.

Technical Service Bulletins (TSBs) & Recalls

• TSB #20-100: 'Warranty Extension: MIL Comes On with DTC P0420/P0430, P030x, and/or P219A/B'. This is the key bulletin extending the warranty for the fuel injector issue to 10 years or 150,000 miles for certain models. It outlines the diagnosis and repair procedure.
• TSB #19-072: 'MIL Comes On with DTC P0430 or P0430 with P030X, P219A, P219B'. An earlier version of the bulletin describing the same injector issue and repair procedure, often requiring a software update.
• TSB #ATI&01302026904: A recent bulletin for the 2025 Pilot where Honda is requesting parts be collected for analysis when P0420/P0430 occurs, indicating ongoing investigation into this issue on the newest generation.

Platform-Specific Known Issues

• {'title': 'Owner Experience: From Injector Warranty to Converter Quote', 'description': 'A user on Reddit with an 2018 Pilot had their fuel injectors replaced under warranty to fix an emissions light. Shortly after, the light returned with code P0430, and the dealer then quoted $3,059 to replace the Bank 2 catalytic converter. This story illustrates the typical progression: the faulty injectors were fixed, but likely not before they had already damaged the catalytic converter, leading to a second, expensive repair.'}

Mechanic-Grade Diagnostic Values

• Low-Pressure Fuel System Pressure at Idle — expected: 380-440 kPa (55-64 psi). Failure: Pressure below this range could indicate a weak fuel pump; pressure above could indicate a faulty regulator. However, this does not test the high-pressure direct injection side.
• High-Pressure Fuel System Pressure Leak-Down — expected: Pressure should hold steady after engine shut-off.. Failure: A rapid drop in pressure (e.g., from over 500 PSI to under 50 PSI in 15 minutes) strongly suggests one or more injectors are leaking fuel into the cylinders.
• Long Term Fuel Trim (LTFT) — expected: Within +/- 10% at idle.. Failure: A consistent negative value beyond -10% (e.g., -15% to -20%) on Bank 2 indicates the PCM is constantly removing fuel to compensate for a rich condition, often caused by a leaking injector.
• Oxygen Sensor Heater Resistance — expected: 10 - 40 Ohms. Failure: A reading outside this range indicates a faulty heater element within the O2 sensor, which can cause incorrect sensor readings, especially when the engine is not fully warmed up.

Scan Tool Commands That Help

• Honda HDS (i-HDS) or compatible high-end scanner (e.g., Autel): Cylinder AF Test — This is the definitive, Honda-specified test to run when P0430 is present, especially with P219B. It varies the air-fuel ratio and counts misfires to pinpoint faulty injectors. A 'fail' result for a cylinder on Bank 2 confirms the injector issue.
• Honda HDS (i-HDS): PCM/ECM Software Update — Required after fuel injector replacement, as per TSBs 19-072 and 20-100. The updated software has revised logic to prevent misinterpreting sensor data that could lead to false P0430 codes.

Wiring & Ground Locations

• Bank 2 Location — The bank of cylinders (and associated catalytic converter/O2 sensors) located closer to the radiator (front of the vehicle).. P0430 specifically refers to Bank 2. Technicians must be certain they are testing and replacing components on the correct bank to avoid wasted time and money.

Real Owner Repair Stories

• Pete's Garage YouTube Channel (2016 Honda Pilot with 50,000+ miles) — Check engine light with codes P0430 (Catalyst Efficiency Bank 2), P219B (Bank 2 Air Fuel Ratio Imbalance), and a pending code for a cylinder 4 misfire.
  ❌ Tried (didn't work) The owner was facing a potential catalytic converter replacement.
  ✅ What actually fixed it The technician identified the known fuel injector issue. The video provides a step-by-step guide showing the replacement of all six fuel injectors, which resolved all the codes.
• Reddit user r/hondapilot (2020 Honda Pilot with 170,000 miles) — Intermittent P0430 code, occasional vehicle bucking. Dealer suggested replacing the catalytic converter based on the code alone.
  ❌ Tried (didn't work) Replaced transmission fluid pressure sensor., Replaced EVAP purge valve., Used two rounds of Techron fuel system cleaner.
  ✅ What actually fixed it The issue was not fully resolved in the thread, but a knowledgeable commenter pointed out that with the provided fuel trim data (LTFT1: -11.7%, LTFT2: -8.6%), the values were not negative enough to definitively point to injectors and suggested that at 170k miles, a valve clearance adjustment should be considered, or it could genuinely be the catalytic converter. This highlights a high-mileage diagnostic path when the injector issue isn't clear-cut.

"I Checked Everything" — The Actual Cause

• The primary documented cause for P0430 on this platform, faulty fuel injectors, will not be found with a smoke test. A smoke test checks for physical leaks in the exhaust system, but the rich condition is caused by excess fuel being commanded or leaking internally through the injector into the cylinder. This is why it's commonly missed by those who default to checking for exhaust leaks first.

OEM Part Supersession History

• 16010-RLV-305 → 16010-RLV-315 — This is a common revision for the fuel injector set. While the exact reason isn't published, part revisions are typically made to improve reliability or change suppliers, directly addressing the known failure pattern.
• N/A → N/A — When replacing the direct fuel injectors, the high-pressure fuel crossover pipe (Honda P/N 16012-R9P-315 or included in kit 06161-RLV-305) is a one-time use part and must be replaced to ensure a proper seal.
  Heads up: Reusing the old pipe can lead to dangerous high-pressure fuel leaks.

Model Year Variations Within This Range

• 2019-2022: These models use the J35Y6 SOHC V6 engine. This engine is well-documented in TSBs 19-072 and 20-100 for the fuel injector issue causing P0430. It has mechanical tappets and requires periodic valve clearance adjustments.
• 2023-2025: These models use the new J35Y8 DOHC V6 engine. This engine ditches VTEC for DOHC heads and uses hydraulic lifters, eliminating the need for valve-lash adjustments. It also features a higher-pressure direct injection system for better emissions. The existence of a TSB from 2026 collecting parts for P0430 on a 2025 model suggests that catalyst efficiency codes are still a concern being monitored by Honda on this new engine.