P0430 on Cadillac
Catalyst System Efficiency Below Threshold (Bank 2)
P0430 on Cadillac vehicles indicates catalyst system efficiency below threshold (bank 2). Au7o has documented this code across 1 Cadillac model — most commonly on XTS. 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 Cadillac range from $900 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 Cadillac by Model
Cadillac XTS(1 issue)
- Catalytic Converter Flange Weld Cracks Causing Exhaust Leak and Cabin Fume Smell (TSB 17-NA-321)2013-2017
On 2013-2017 XTS with the 3.6L LFX V6, the weld at the catalytic converter mounting flange cracks, producing an exhaust leak at the front of the engine. Owners first notice a ticking or hissing that sounds like an intake or valvetrain noise on cold start, followed by an exhaust smell inside the cabin and eventually P0420/P0430 catalyst-efficiency codes as the leak upsets the downstream oxygen sensor reading. GM documented the condition first in preliminary information PIP5419 and then in TSB 17-NA-321 (November 2017), which calls for converter replacement rather than weld repair. The bank 2 (front) converter is the usual failure point.
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What does P0430 mean on Cadillac?▼
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 Cadillac specifically, this code is documented across 1 model.
What causes P0430 on Cadillac vehicles?▼
Common causes on Cadillac: 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 Cadillac?▼
Repair costs on Cadillac range from $900 to $2,000, depending on the specific model and root cause.
Which Cadillac models have P0430 documented?▼
Au7o has documented P0430 on 1 Cadillac model: XTS.