I’m experiencing a persistent P0430 code on my 2014 Chevy Silverado 1500 LT with 170K miles, even after replacing the catalytic converter and O2 sensor. About a month ago, the check engine light illuminated, indicating a P0430 code. Following standard troubleshooting, I replaced the downstream O2 sensor and cleared the code. For a brief period, the issue seemed resolved. However, the check engine light reappeared with the same P0430 code roughly a month later. Thinking the catalytic converter might be the culprit, I had a muffler shop replace it and again cleared the code. Unfortunately, just two days later, the check engine light was back, still displaying the P0430 code.
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I came across some information suggesting that an engine temp sensor malfunction could potentially cause a P0430 code. The theory is that if the engine computer receives incorrect temperature readings, it might lead to a consistently rich fuel mixture. This rich mixture could then affect the readings of the O2 sensors and trigger the P0430 code, even if the catalytic converter itself is functioning correctly. It’s mentioned that if the computer misinterprets the engine temperature, it will maintain a richer fuel mixture than necessary. This excess fuel in the exhaust could throw off the O2 sensor readings, leading to the P0430 error.
I’ve also noticed a significant amount of black soot around my exhaust tips, which I understand can be a sign of running rich. This observation further strengthens my suspicion about the fuel mixture being too rich.
Has anyone else encountered a similar situation with the P0430 code Chevy? Specifically, has anyone replaced both O2 sensors and the catalytic converter, only to have the P0430 code return? If so, what was the ultimate solution? Could a faulty engine coolant temperature sensor be the underlying problem in this case? Given the relatively low cost of the engine temp sensor (around $40), it seems like a worthwhile component to investigate and potentially replace. Any insights or experiences with resolving a persistent P0430 code on a Chevy Silverado after addressing the usual suspects would be greatly appreciated.
