P0430 on GMC
Catalyst System Efficiency Below Threshold (Bank 2)
P0430 on GMC vehicles indicates catalyst system efficiency below threshold (bank 2). Au7o has documented this code across 1 GMC model — most commonly on Canyon. 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.
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 GMC by Model
GMC Canyon(1 issue)
- P0420/P0430 Catalytic Converter Efficiency Failure (3.6L V6)2015-2022
On the 3.6L V6 (LGZ) Canyon, the catalytic converters lose efficiency and trigger P0420 (Bank 1) and/or P0430 (Bank 2), often a downstream consequence of the engine's PCV-related oil consumption that contaminates the converter substrate and O2 sensors. Both converters can fail around similar mileage since they age under identical conditions.
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View P0430 across all makes →Frequently Asked Questions
What does P0430 mean on GMC?▼
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 GMC specifically, this code is documented across 1 model.
What causes P0430 on GMC vehicles?▼
Common causes on GMC: 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 GMC?▼
Repair costs vary widely depending on the root cause and specific GMC model.
Which GMC models have P0430 documented?▼
Au7o has documented P0430 on 1 GMC model: Canyon.