Silverado P0430 Code Reappears After Replacement of Y-Pipe and Sensors at 204,000 Miles
At 204,000 miles, I replaced the Y-pipe with converters, all four oxygen sensors, and cleared the fault codes. Initially, everything appeared to be functioning properly. However, after a few days of driving, the MIL light reactivated with the P0430 code—specifically showing as P0430$07E8 on my OBD2 scanner. I have attempted to clear the code multiple times, but it returns consistently. I do not believe there is a significant exhaust leak, though a very small one cannot be ruled out. Given that all components were replaced and the system initially passed diagnostics, what could be causing this persistent P0430 fault? Any insights or troubleshooting steps for Silverado owners experiencing this issue?
A P0430 code typically indicates one or more of the following: The catalytic converter is no longer functioning properly, an oxygen sensor is not reading accurately, or there is an exhaust leak. For Silverado owners, especially at high mileage, it's important to verify that all components—such as the Y-pipe and sensors—are fully installed and securely connected. A small exhaust leak may not trigger a strong signal but can still cause intermittent P0430 readings. Consider checking for loose connections or using a smoke test to detect minor leaks. Also, ensure the OBD2 scanner is properly calibrated and that the code is not being triggered by a sensor misreading due to contamination or age.