EGR codes p1404 & p0404
 

P1404 egr stuck closed and P0404 exhaust gas recirculation control circuit range/performance.
This is on a 99 Suburban SB350 that belongs to my neighbor.
Not sure what to replace to fix this anyone done this before? Napa says there’s an EGR control solenoid ($30) and a EGR for $179. Not sure how to test these. Is there a simple test to determine what need to be replaced?
s/t

Re: EGR codes p1404 & p0404
 

pop the EGR off clean with carb clean and put back on clear codes but let runn at idle if gets hot hot replace if not probally solinoid just a test i'd do

Re: EGR codes p1404 & p0404
 

DTC P1404 Exhaust Gas Recirculation (EGR) Closed Position Performance
DTC P0404 Exhaust Gas Recirculation (EGR) Open Position Performance
This vehicle uses a linear egr that has the control and valve all in one unit. With these codes it's pretty common to see some small pieces of carbon stuck in the egr pintle holding it open. I'd pull the egr valve off and check for this. I won't tell you to replace it but If it was mine and I didn't find anything in it I'd replace it.

Re: EGR codes p1404 & p0404
 

Back yard 88 is correct , this is a linear egr, and they had problems with debri holding open the pintle, usually associated with low vacuum and poor power brake operation, due to fact egr is hung open and can drop vacuum causing poor brake booster vacuum,
This egr also has the position sensor inside the egr, understanding this , if the computer commands the egr percentage on a certaing degree and the position sensor doesnt match, it will flag a code. I usually use a scanner for a quick test , I will command the egr on and than monitor the actual egr opening, if it matches I look elsewhere, I have changed many intake manifold gaskets due to debri in egr, the debri comes from the combusiton chamber, it breaks off and gets under egr pintle, tomco does make a gasket that can be used under egr to correct for this problem, it has a screen to stop debri from hanging pintle open, but keep in mind , if over time enough debri plugs screen , you will set a code for lack of egr flow.
not knowing if you have a debri issue or position input issue or an actual egr function issue, ??? This egr uses one twelve volt wire and the rest of the wires are ground control from the computer, each wire other than the 12v wire controls the amount of pintle opening and egr flow, if you dont have a scan tool to command egr to open , you can find schematic and unhook connector at egr, send 12volts w/ jumper wire to terminal on egr that is the 12v term. and while engine running touch each of the other wires with ground, engine should stumble at idle with any degree of egr flow, more so with one and so on and so on..... good luck