Hi Everyone,
I have searched high and low and have not been able to fix my p0403 EGR code. I have done the tests and everything checks out good. I get 5v at pin "D", I gey .7v at pin "C" , pin "A" has good ground. Pin "B" is ground provided by the pcm but I still get a ground with the key off engine off. I get nothing on pin "E" with key on or off. Am I supposed to get 12v with KOEO? Replaced EGR valve and cleaned out the passage and code is still there. Is my ECM fried? Thanks all!

 

Hi !
Read here Part 1 -GM EGR Valve Test (P0401, P0403, P0404, P0405)
I hope this will help you

 

Thanks for the reply. That's the source I am using to trouble shoot this code. I followed the steps and I ended up replacing the EGR since the test results pointed that way but the code still comes on. I traced all the wires to the ecm and none are damaged.
Cliff notes:
-EGR passage is not clogged
-new EGR valve
-pin A has good ground
-pin B has good ground with car off, is this only supposed to have ground with the key on?
-pin C has .7 volts
-pin D has 5 volts
-pin E I get nothing. Does this pin energize only when the pintle reference goes up?

Are there any other sensors associated with the EGR?
I tried energizing the EGR with a 9 volt battery to see if engine would stall but I don't think the battery is strong enough to keep the solenoid open as it spitters a little and then idles fine.
Thanks all

 

I hate to ask the obvious but after you changed the EGR did you clear the set code(s) such that it keeps coming back? I hope it is just that simple, other than that I've got nothing. Good luck.

 

I did. As soon as I clear the code and if I plug in the scanner again the code is there pending. I unplug the scanner and turn the van on and the CEL is turned on. I opened the ECM but saw nothing out of the ordinary. I didn't unacrew the board to look on the other side though. If I get a used ECM what do I have to do to make it work?
Thanks again

 

I supplied 12v manually to the EGR while van was running and it shut off. This just confirms the passage way is not clogged. I disconnected the EGR exhaust tube and I am getting exhaust flow, doesn't seem to be clogged. I opened the valve on the old EGR manually and stuck a pin to hold the valve open then I connected the EGR harness and took a reading of the pintle sensor and got a higher reading then when it is fully closed. I am
Not sure what this means but maybe the old EGR valve was not defective? Also opened up the ECM again and this time I flipped the board over and everything is clean, no burn marks nothing. Any input is appreciated. Thanks!

 

UPDATE:
I got the problem fixed. Pin E was corroded at the connector.
Learn from my mistake and check continuity between wires. Just because they look good doesn't mean they are.
Thanks