P0430
Medium SeverityCatalyst System Efficiency Below Threshold (Bank 2)
Emissions System
P0430 — Instant Answer
Catalyst System Efficiency Below Threshold (Bank 2)
Severity: MEDIUM SEVERITY
Meaning: Same as P0420 but on bank 2. If both P0420 and P0430 are present, the issue may be systemic (engine running rich, etc.).
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $100 - $1,500
Most common causes:
- 1. Worn catalytic converter bank 2 (35-45% of cases)
- 2. Faulty downstream O2 sensor bank 2 (10-25% of cases)
- 3. Rich-running engine damaging both cats (10-25% of cases)
Common Causes
How to Diagnose P0430
- 1Same approach as P0420 but on bank 2
- 2If P0420 also present, check for engine-wide rich condition first
OEM Procedures for P0430
P0430 affects the Catalytic Converter. Found 98 OEM service manual procedures.
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Adjustment/Replacement - Inspection
Showing 8 of 98 procedures
OEM Diagnostic Flowchart
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Parts & Tools for This Job
Common parts shoppers buy for P0430 Catalyst System Efficiency Below Threshold (Bank 2).
Oxygen Sensor
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Catalytic Converter
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EVAP Purge Valve
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Gas Cap
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OBD2 scanner
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Check SpecificationsBattery tester
Check cranking and charging health before replacing expensive parts.
A weak battery can mimic alternator or starter problems.
Check SpecificationsMultimeter kit
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0430.
OEM Manual Evidence
Browse →Catalytic Converter DTCS — 2013 Acura MDX 3.7L Eng VIN 2 Service Manual ~ LEMON Manuals LEMON Manuals: Repair Knowledge Reimagined Home >>...
Catalytic Converter DTCS — 2013 Acura MDX 3.7L Eng VIN YD2 Service Manual ~ LEMON Manuals LEMON Manuals: Repair Knowledge Reimagined Home >...
Engine Control System - Advanced DTCS — 2013 Acura RDX 3.5L Eng VIN 3 Service Manual ~ LEMON Manuals LEMON Manuals: Repair Knowledge Reimag...
Engine Control System DTCS — 2013 Acura RDX 3.5L Eng VIN 3 Service Manual ~ LEMON Manuals LEMON Manuals: Repair Knowledge Reimagined Home >...
Related Symptoms
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Exact Repair Workflows
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Open the exact repair flow most commonly associated with P0430 on this vehicle.
Open the exact repair flow most commonly associated with P0430 on this vehicle.
Related Codes
The catalytic converter on bank 1 is not converting pollutants efficiently. This is one of the most common DTCs.
Bank 2 warm-up cat efficiency code.
General fault in the downstream O2 sensor on bank 2.
Frequently Asked Questions
- Why do I have P0420 AND P0430?
- Both cats failing together usually means something is damaging them — running rich, oil consumption, or coolant entering combustion.
- Can I use aftermarket catalytic converters?
- In many states, yes. In California, you must use CARB-compliant converters. Aftermarket cats are much cheaper than OEM.
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Author & Review
Published by AllOEMManuals, founded by Lyndon Bedford, an automotive technician with 20 years of experience. He owned and operated a mechanic shop in Hurst, Texas from 2014 to 2022 and continues hands-on repair work.
Content may combine manual references, general repair templates, and AI-assisted drafting. Confirm the source, vehicle configuration, and applicability before working. Report corrections through our contact page.
Last updated: 2026-11-07