What can still be causing the p2432 code on my car after replacing entire SAI.

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. First, I will need to know which engine is in your Impala, the 3.5L or 3.9L V6. Second - the trouble code definition is: "Secondary Air Injection (AIR) System Pressure Sensor Circuit Low Voltage". This code does not condemn any specific part - yet many were replaced. What testing has been performed to isolate the concern to its root cause? There is a multiple step diagnostic routine that must be followed, utilizing a diagnostic tool as well as voltmeter to make measurements and lead to the source of failure. I suspect some kind of wiring or power supply concern. But it's a big guess from where I stand; hands on testing is needed. Reach out to a shop near you for help -- https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.