Well this vehicle is a hard one to work on. Not sure why the mechanic tried an air filter or fuel filter. being the code is actually p0411 you need to troubleshoot the air injection system first as this would be the most likely issue since the check engine light has come on indicating this.
Are there any other trouble codes?
here is some information in regards XXXXX XXXXX next steps that need to be taken in order to resolve this issue. Follow the flow chart
CIRCUIT DESCRIPTION The purpose of the Secondary Air Injection (AIR) system is to reduce Hydrocarbon (HC) , the Carbon Monoxide (CO) , and the Oxides Of Nitrogen (NOx) exhaust emissions by causing any combustible gases in the exhaust to reburn. This also causes the catalytic converters and the Heated Oxygen (HO2S) sensors to reach the normal operating temperatures more quickly, which will allow Closed Loop operation to occur earlier.When the engine is started, the Engine Control Module (ECM) commands the AIR pump relay and the AIR cutoff valve vacuum control solenoid ON, injecting clean air into the engine exhaust ports. The ECM switches the AIR system OFF when the oxygen sensors become active. The AIR cutoff valve prevents air from being drawn into the system when the AIR pump is OFF. The vacuum to the valve is controlled by the AIR cutoff valve vacuum control solenoid. A check valve close to the engine prevents hot exhaust gases from backing up into the AIR system.CONDITIONS FOR RUNNING THE DTC The following DTCs are not set: P0110, P0115, P0116, P0130, P0131, P0132, P0134, P0150, P0151, P0152, P0154, P0171, P0172, P0174, P0175, P0300-P0306, P0412, P0418, P0440, P0442, P0443, P0446 or P0455.
CONDITIONS FOR SETTING THE DTC The ECM has determined that reduced or no secondary air flow is present.ACTION TAKEN WHEN THE DTC SETS The ECM illuminates the Malfunction Indicator Lamp (MIL) and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.
hope this helps
Accepts greatly appreciated