[bejuco34]

I have change the egr,vacuum hoses still give me the same code po401,po402

[stich626]

lets start with the basics..WHAT ENGINE?

5.4v8 or the v10

[T-bucket23]

Originally Posted by bejuco34

I have change the egr,vacuum hoses still give me the same code po401,po402

This is usually due to the ports that feed the egr valve being plugged or the hoses that run from the exhaust back up to the EGR housing being plugged or damaged or it could be a bad DPFE sensor

[stich626]

Originally Posted by T-bucket23

This is usually due to the ports that feed the egr valve being plugged or the hoses that run from the exhaust back up to the EGR housing being plugged or damaged or it could be a bad DPFE sensor

hyjack, where in ma.

[LATECH]

P0401 is EGR insufficient flow
P0402 is EGR excessive flow
These 2 together could be a little tough, but I agree with T Bucket PROBABLY the DPFE sensor , if you replace it get a for one, not aftermarket, also replace the 2 hoses that go to it.Without a thorough diagnosis its a gamble.
A code reader will give codes, but unless you can view live data you cant diagnose it to be positive.It could also be the EGR valve sticking open or shut, or the EGR regulator solenoid not passing vauum or holding vacuum too long , That would be about the only scenarios that would generate both codes, other than someone unplugging stuff with the key on.

code readers sell parts, A Diagnostic Tech reading live data will repair the problem without just throwing parts at it.

[sbchevfreak]

A Diagnostic Tech reading live data will repair the problem without just throwing parts at it.

X1000!
Any monkey can throw parts, it takes training and skill to accurately diagnose and repair the first time.

That said, I would lean towards the DPFE, as well. Should do the pinpoint tests, just to confirm.

[T-bucket23]

Originally Posted by stich626

hyjack, where in ma.

Central MA Worcester