P0441 OBD2 Code in 1996 Chevrolet Corsica 3.1L - EVAP System Pressure Issue
I recently encountered a recurring P0441 diagnostic trouble code (DTC) on my 1996 Chevrolet Corsica 3.1L engine after resolving a previous P0302 misfire issue. To fix the P0302, I replaced the fuel injector on cylinder #2, having already ruled out faulty spark plugs, ignition wires, and performed compression tests on cylinders 2, 4, and 6. Instead of fully removing the airbox and plenum, I only moved them aside during maintenance. Upon reassembling, I noticed that the air intake sensor had popped out of its mounting in the airbox. I assumed it was a minor issue and simply reinstalled it without further inspection. Shortly after, the vehicle triggered a P0441 code — indicating an EVAP system pressure regulation failure. When I attempted to diagnose this by inspecting the system, I inadvertently damaged the air intake sensor during handling, which resulted in a new P0113 code (intake manifold absolute pressure sensor circuit high). After replacing the sensor and resetting the ECU, the P011-3 code disappeared but the P0441 returned. I have now replaced the air intake sensor again, yet the P0441 persists. I am running out of time to pass emissions testing and need help identifying the root cause. The vehicle is a 1996 Corsica with a 3.1L engine that was originally sourced from a 1996 Chevrolet Grand Prix — could there be differences in EVAP system design or component placement between these models? I have not replaced any vacuum lines, but I suspect one may be disconnected, cracked, or damaged during the previous work. The P0441 code appears to be related to pressure regulation failure, and from ALLDATA and Mitchell diagnostics, this suggests a leak in the evaporative emissions system. My question: Does the Powertrain Control Module (PCM) store only one code per incident? Why did damaging the air intake sensor trigger a P0113 rather than an additional P0441? I reset the codes after replacing the sensor, but not before. Currently, only the P0441 is stored — no check engine light is illuminated. I kept the original engine and transmission assembly intact; only the alternator and fuel rails with injectors were replaced. Any insight into EVAP system behavior in this model or potential vacuum line issues would be greatly appreciated.
Could there be a damaged or disconnected vacuum hose in the EVAP system? These are common culprits for P0441, especially after modifications near the intake area. Check all lines under the hood, particularly those connected to the fuel tank vapor pressure control valve and the air intake sensor housing.