Cleaning Rear Catalytic Converter - On Vehicle - P0420 Code - 2011-2017 Odyssey Touring Elite

⚡ Update: Check the pinned comment below for long-term results and additional insights.

In this video, I attempt to clear a P0420 Catalyst System Efficiency Below Threshold (Bank 1) code on our 2011 Honda Odyssey Touring Elite using a chemical catalytic converter cleaner. I removed the upstream O2 sensor from the rear catalytic converter and sprayed the cleaner directly into the cat.

Using Lucas Fuel Injector Cleaner has kept the idle stumble gone, and the CEL (P0420) to stay off. This approach seems to have resolved both minor injector issues and improved catalytic efficiency.

⚠️ Common Issue on Honda/Acura 3.5L V6 with VCM
Bank 1 catalytic converter clogs or P0420 codes are a common problem on J35 V6 engines with Variable Cylinder Management (VCM). Cooler exhaust temps & oil pulled into the combustion chamber during deactivation then burnt when re-activated, causes carbon buildup and premature catalyst issues.

🛠️ Note: This same process can also be tried for a P0430 (Bank 2) code on the front catalytic converter.

🔧 Applicable Honda/Acura 3.5L V6 with VCM:
Odyssey (2008–2023), Pilot (2009–2023), Accord V6 (2008–2017), Crosstour V6 (2010–2015), Ridgeline (2009–2014), Acura MDX/RL/TL (2007–2014)

If your vehicle runs the J35 V6 with VCM, Bank 1 often behaves the same way.

🛠 Symptoms:
• Check Engine Light (CEL) illuminated, often P0420 or P0430
• Slight idle stumble or misfire at low RPMs
• Decreased fuel efficiency
• Rough or uneven acceleration
• Occasional hesitation under load
• Strange exhaust odor (sulfur/rotten egg) in severe cases
🧰 Difficulty Level: Beginner
⏱️ Estimated Time: 30min–1 hour

🧰 Products & Tools Used in This Video
🔹DPF / Catalytic Converter Cleaner - https://amzn.to/4kMYBdg
🔹Cataclean - https://amzn.to/4n4yQXD
🔹O2 Sensor Socket - https://amzn.to/4eahZ1n
🔹Borescope - https://amzn.to/3G6UpWE
🔹3/8 dr. 18 in. Breaker Bar - https://amzn.to/4pL3aH8
🔹Mouse Milk Penetrating Oil - https://amzn.to/41k1wTl
🔹Precision Oiler - https://amzn.to/4nNTEC8
🔹Lucas Injector Cleaner - https://amzn.to/4oUlz3I
🔹Lucas Injector Cleaner (GALLON) - https://amzn.to/4psmHN0

📸 My Gear & Tools:
🎥 GoPro 11 Black - https://amzn.to/45AcxAT
🎬 Edited in Wondershare Filmora 14 - bit.ly/MattMechanicFilmora
🎛️ Controller: TourBox Elite Plus - https://amzn.to/4l5l6JJ
🖼️ Thumbnails: GIMP + TourBox

📌 Chapters
00:00 – Intro & P0420 Overview
00:22 – Previous Cataclean Experience & Issue Returning
01:19 – Choosing a Stronger Cleaner (DPF/Cat Cleaner)
01:39 – Preparing O2 Sensor & Using Penetrating Oil
03:00 – Checking Rear O2 Sensor Location
06:03 – Confirming P0420 Code on Bank 1
08:57 – Verifying Rear vs. Front Catalytic Converter
12:06 – Disconnecting Sensor Connectors Safely
15:05 – Removing Rear O2 Sensor (Breaker Bar & Ratchet Tips)
22:28 – Preparing for Catalyst Cleaning
23:27 – Engine Warm-Up Considerations
24:21 – Spraying Cleaner Into Catalytic Converter
25:59 – Using Boroscope to Inspect Inside Cat
30:15 – Inserting Cleaner & Proper Distribution Technique
36:04 – Test Drive Instructions (40 Minutes to Burn Deposits)
40:51 – After Test Drive Observations & Boroscope Check
42:10 – Resetting Codes & Next Steps for Long-Term Follow-Up
44:30 – Wrap-Up & Teaser for Follow-Up Video

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Disclaimer: I am a licensed Airframe & Powerplant (A&P) mechanic ✈️, but I am not a licensed automotive technician🚗. The content in this video is for educational and entertainment purposes only. Always consult a certified mechanic or your vehicle’s service manual before attempting any repairs or modifications. You are responsible for your own tools, safety, and decisions. Use this content at your own risk.