P0430 on Dodge
Catalyst System Efficiency Below Threshold (Bank 2)
P0430 on Dodge vehicles indicates catalyst system efficiency below threshold (bank 2). Au7o has documented this code across 2 Dodge models — most commonly on Challenger, Stealth. 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 Dodge range from $40 to $2,379, 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 Dodge by Model
Dodge Challenger(2 issues)
- HEMI Exhaust Manifold Bolt Failure2008-2023
Exhaust manifold bolts break due to thermal cycling causing the bolts to become brittle and snap, especially on the passenger side. Dissimilar metals (iron manifold, aluminum head) accelerate the process. Creates a ticking noise at cold startup. Common across all HEMI-powered LX/LC platform vehicles.
- Catalytic Converter Efficiency Code (P0420 / P0430)2008-2023
A P0420 ("Catalyst System Efficiency Below Threshold, Bank 1") or P0430 ("Bank 2") check-engine light is one of the most common emissions codes on the Dodge Challenger, especially on higher-mileage V8 cars. The PCM sets the code when it compares the upstream (pre-cat) and downstream (post-cat) oxygen-sensor signals: if the downstream sensor begins to mimic the rapidly-switching upstream sensor instead of staying relatively flat, the computer concludes the converter is no longer storing/releasing oxygen efficiently. On the Challenger this code is frequently NOT a worn-out converter at all. The two most common upstream root causes are (1) an exhaust leak from broken exhaust-manifold bolts — the well-documented "HEMI tick" on the 5.7L and 6.4L V8s — which lets atmospheric oxygen into the exhaust stream and confuses the rear O2 sensor, and (2) a long-running misfire (worn plugs, failing coils, leaking injectors on the 3.6L Pentastar) that dumps raw fuel into the converter and physically destroys it over time. A failed downstream O2 sensor, contaminated converter (from an oil-cooler/oil-filter-housing leak on the Pentastar), or simply an aged/degraded cat round out the causes. Chrysler also issued software bulletins (TSB 18-021-12, superseded by 18-033-13) because early PCM calibration logic was overly sensitive and could trigger false P0420/P0430 codes — particularly in warm weather or on long highway drives — so a PCM reflash should be ruled out before any hardware is replaced. Because the converter sits in the federal/CARB emissions-warranty window for many of these cars, the diagnosis order matters a lot to the owner's wallet.
Dodge Stealth(1 issue)
- Active Exhaust System (AES) Valve Failure1991-1996
The Dodge Stealth (particularly RT/TT and ES models) features an Active Exhaust System with electronically controlled valves that open at higher RPM to reduce backpressure. These valves seize from rust and carbon buildup, causing restricted exhaust flow, reduced power, and a check engine light. The vacuum-actuated system uses solenoids and diaphragms that also fail with age. Many owners simply remove the system entirely and replace with a straight-through exhaust, which provides better performance and eliminates the failure point. The AES is shared with the Mitsubishi 3000GT as both cars were built on the same platform.
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View P0430 across all makes →Frequently Asked Questions
What does P0430 mean on Dodge?▼
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 Dodge specifically, this code is documented across 2 models.
What causes P0430 on Dodge vehicles?▼
Common causes on Dodge: 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 Dodge?▼
Repair costs on Dodge range from $40 to $2,379, depending on the specific model and root cause.
Which Dodge models have P0430 documented?▼
Au7o has documented P0430 on 2 Dodge models: Challenger, Stealth.