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The P0404 and P0406 are directly related. These codes are pointing to a fault with the EGR Position Sensor. On this engine, the Position Sensor is built into, and part of the EGR Valve. Inspect the electrical connector for any loose or broken wires. If the visual inspection checks ok, replacing the EGR Valve should solve the problem. It's actually a very common, high-rate fail item.
The P0456 is pointing to a Small Leak in the EVAP (emissions control/recovery) System. This one is a bit harder to diagnose. There area few different things that can set this code. First- check the Fuel Cap. Make sure it is tight. Inspect the underside of the cap for any visual defects. If there is any doubt, replace the cap. Keep in mind, the cap needs to meet OE specs, so those "universal" or "discount" caps they sell at AutoZone will not solve the problem. If the cap is knwon to be good, the next item to check is the EVAP Purge Solenoid. Inspect the vacuum lines to/from the solenoid for any cracks, holes or loose/missing connections. Verify the operation of the solenoid. If the slenoid checks ok, next inspect the Leak Detection Pump. Again, carefully inspect the vacuum lines and verify operation of the pump. If these items all check ok, the next best way to diagnose this, is to have the EVAP system "smoked". This is where a machine forces smoke through the system, and the "small leak" will reveal itself.