P0430: Catalyst System Efficiency Below Threshold (Bank 2)
50 vehicles · 19 makes · $40-$6,000 repair
Most Reported On
P0430 is an OBD-II diagnostic trouble code meaning “Catalyst System Efficiency Below Threshold (Bank 2).” This code means the catalytic converter on Bank 2 (the side of the engine that does not contain cylinder #1) is not reducing emissions as effectively as it should. The computer compares the readings of the oxygen sensors before and after the converter; if the downstream sensor's signal starts mirroring the upstream one, it indicates the converter is no longer storing and processing oxygen properly. This usually points to a worn-out or damaged catalytic converter, but it can also be caused by faulty sensors or upstream engine problems that have poisoned the converter. The car will generally still run, but it will fail an emissions test. This code is most commonly reported on 2007-2019 Toyota Tundra (1794 Edition, Base, Limited, Platinum, SR, SR5, TRD Pro), 2004-2012 Mazda RX-8, and 2006-2019 Volkswagen Beetle, plus 47 other vehicles, with repair costs ranging from $40 to $6,000.
Common Causes
Typical Repair Cost
Based on 56 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0430, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (50)
Broken Exhaust Manifold Bolts on 5.3L/6.2L V8 Causing Exhaust Tick and False P0420
P0430 — Catalyst Efficiency Below Threshold (Bank 2) from Aged/Failed Rear-Bank Converter on the V6
P0430 — Bank 2 Catalytic Converter Efficiency Loss on V6 Equinox
Catalytic Converter Theft Vulnerability (High Ground Clearance, Easily Accessed Converters)
Exhaust Manifold Bolt Failure
PTU (Power Transfer Unit) Failure
Exhaust Manifold Studs / Bolts Break — Exhaust Leak and Cold-Start Ticking
Catalytic Converter Efficiency Failure — P0420/P0430 (Triton V8)
P0430 — Failed Bank 2 Catalytic Converter on 3.0L Duratec V6 Escapes
P0430 — Bank 2 Catalytic Converter Efficiency Loss (Driver-Side Cat, TSB 19-2201)
Catalytic Converter Failure (First Gen)
Catalytic Converter Efficiency Failure Triggering P0420 / P0430
Premature Catalytic Converter Failure - P0420 / P0430 Low Efficiency
Exhaust Manifold Stud Breakage and Exhaust Leak Tick on 3.2L V6
4.0L Inline-6 Exhaust Manifold Cracking
Exhaust Manifold Bolt Failure and Manifold Leak on 4.7L V8
2018 Trackhawk P0420/P0430 - Apply TSB 18-001-26 Before Buying Parts
P0430 — Failed Driver-Side (Bank 2) Catalytic Converter on the Pentastar/3.8L V6
Catalytic Converter Overheating and Engine Piston Damage
Catalytic Converter Premature Failure
P0430 — Catalyst Efficiency Below Threshold (Bank 2) on the Lambda V6, Failed Cat or Rear O2 Sensor
Exhaust Manifold Bolt Failure and Leak
Catalytic Converter Theft Vulnerability
Premature Catalytic Converter Failure
Catalytic Converter Premature Failure (Bank 1)
Catalytic Converter Low Efficiency (P0420) and High Theft Vulnerability
Catalytic Converter Efficiency Failure (P0420) on the QR25DE
Exhaust Manifold Cracking
Premature Catalytic Converter Failure
Exhaust Manifold Cracking (Both Banks)
Exhaust Manifold Cracking and Bolt Failure
Pre-Catalytic Converter Disintegration (Spyder)
Exhaust Manifold Cracking (4.7L 2UZ-FE V8)
Catalytic Converter Efficiency Failure Causing P0420 Check Engine Light
P0430 — Bank 2 Catalyst Efficiency Loss from Aged Converter / Worn Downstream O2 Sensor
Catalytic Converter Efficiency Failure — P0420 / P0430 Check Engine Light
Pre-Catalytic Converter Disintegration
Cracked Exhaust Manifolds on 4.7L V8 Causing Ticking Noise and Exhaust Leaks
Catalytic Converter Efficiency Below Threshold (P0420 / P0430) — Aging or Manifold-Integrated Cats
FAQ
What does P0430 mean?
P0430 stands for "Catalyst System Efficiency Below Threshold (Bank 2)." This code means the catalytic converter on Bank 2 (the side of the engine that does not contain cylinder #1) is not reducing emissions as effectively as it should. The computer compares the readings of the oxygen sensors before and after the converter; if the downstream sensor's signal starts mirroring the upstream one, it indicates the converter is no longer storing and processing oxygen properly. This usually points to a worn-out or damaged catalytic converter, but it can also be caused by faulty sensors or upstream engine problems that have poisoned the converter. The car will generally still run, but it will fail an emissions test.
What are the most common causes of P0430?
The most common causes of P0430 are: Worn-out or failed catalytic converter (Bank 2), Faulty downstream (post-cat) oxygen sensor, Faulty upstream oxygen sensor giving bad data, Exhaust leak near the converter or sensors, Engine misfire or oil/coolant burning that damaged the catalyst, Running too rich or too lean over time, Aftermarket or non-compliant catalytic converter. The specific cause varies by vehicle.
How much does it cost to fix P0430?
Repair costs for P0430 range from $40 to $6,000, depending on the vehicle and root cause.
Which vehicles are affected by P0430?
Au7o has documented P0430 across 50 vehicle models from 19 manufacturers: Chevrolet, Chrysler, Dodge, Ford, GMC, Honda, Hyundai, Jeep, Kia, MINI, Mazda, Nissan, Opel, Porsche, RAM, Ram, Subaru, Toyota, Volkswagen.
Sources (12)
- Forum2015 Kia Soul Engine Issues Failed cat converter - Kia Soul Forums
- ForumBlown Engine Due to Catalytic Convertor - Kia Soul Forums
- ForumThe Dreaded Soul Catalytic Converter Issue - Kia Soul Forums
- ForumFAILED CATALYTIC CONVERTER NOW ENGINE COMBUSTION FAILURE - Kia Soul Forums
- newsNV200 Prime Target for Catalytic Converter Theft
- Forum1ZZ Pre-Cat Engine Failures - MR2 SpyderChat
- ForumCatalytic Converter Engine Failures Post Yours - MR2 SpyderChat
- ForumPre-cat failure - not overseas myth - MR2 Owners Club NZ
- ForumPre Cat Cat Failure - MR2 SpyderChat
- ForumJeepForum threads on 4.7 exhaust manifold bolt breakage and ticking
- ForumMiniForums Thread Discussing Exhaust Manifold Cracking on N18 Turbo Engines
- videoYouTube Repair Video: Replacing Cracked Exhaust Manifold on MINI GP Turbo
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.