2003 Volkswagen Passat Trouble codes (MIL On) (Emissions)

P0456 EVAP small leak, can be difficult to track down... a smoke machine would help, but depending on where the gas fumes are leaking, might also not be of much help.

P0411 is usually a simple repair / fix, but just like the EVAP system, there are several components to the Secondary Air System that could cause that coud to be set.

A sample P0411 video of checking components: (1.8T Jetta, same system as your Passat)

This is one of my old videos (no text overlay)... any questions, just leave a comment.

Thomas

Thanks Thomas, Great help. Hopefully I can get it fixed as it's very annoying and worrying having the MIL light on all the time.

Kevin.

Sorry Thomas to bother on but I was doing a coolant flange replacement on my 1.8T, now with that being said, I removed the combi valve which COULD be one of the cause to my code. I inspected the combi valve and found dirt, little pieces of what seems to be like rust. Could this mean my combi valve needs replacement as well as the sec. Air pump as it might have water?

When the combi valves stick open slightly (from age / carbon build-up), warm exhaust enters the SAI System and the warm air then condenses when the engine is off, forming water in the pump and rust on metal components.

You can test the valve just like I did in the above video, by applying vacuum to the vacuum port and blowing through the valve. The valve should pass air when vacuum is applied, but no air when vacuum is off,

If you can blow through it with no vacuum applied, replace the valve.

Make sure that the gasket is not blocking the flow of air between the head & combi valve.

As long as you can hear the SAI pump run (on cold starts), the pump should be ok.

Thomas

PO411 inspect the air pump housing. Make sure it is not split or cracked. Also try to apply power to air pump and check air flow. If all is ok remove the hose at check valve and see if there is exhaust gases pumping out. If there is replace the check valve. Valve is a one way valve only. Also inspect air injection hoses to verify they are all secured and snapped on tight. The other code is for a small evap leak. You would need to smoke test the lines for leaks.