P0430 on Honda
Catalyst System Efficiency Below Threshold (Bank 2)
P0430 on Honda vehicles indicates catalyst system efficiency below threshold (bank 2). Au7o has documented this code across 2 Honda models — most commonly on Insight, Passport. 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. Typical repair costs on Honda range from $300 to $2,000, depending on the specific model and root cause.
Common Causes of P0430
- •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
P0430 on Honda by Model
Honda Insight(1 issue)
- Catalytic Converter Failure (First Gen)2000-2006
The 2000-2006 Honda Insight (first generation) experiences premature catalytic converter failures. The lean-burn engine runs very lean, putting extra stress on the catalytic converter. Symptoms include check engine light with P0420/P0430 codes, rattling noise from exhaust, reduced power, and failed emissions test. OEM Honda catalytic converter: $1,200-2,000. Aftermarket: $400-800.
Honda Passport(1 issue)
- Exhaust Manifold Stud Breakage and Exhaust Leak Tick on 3.2L V62000-2002
The 3.2L V6 used in the first-generation Passport is known to develop exhaust leaks from broken manifold studs or warped manifold sealing surfaces as the vehicle ages. Owners commonly describe a ticking noise on cold start, exhaust smell, and occasional failed emissions testing. Heat cycling and corrosion are the usual causes, and the repair can become labor-intensive if studs snap flush in the cylinder head.
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View P0430 across all makes →Frequently Asked Questions
What does P0430 mean on Honda?▼
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. On Honda specifically, this code is documented across 2 models.
What causes P0430 on Honda vehicles?▼
Common causes on Honda: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0430 on a Honda?▼
Repair costs on Honda range from $300 to $2,000, depending on the specific model and root cause.
Which Honda models have P0430 documented?▼
Au7o has documented P0430 on 2 Honda models: Insight, Passport.