Jump to content



Photo
- - - - -

P0405 Code Driving Me Crazy


  • Please log in to reply
2 replies to this topic

#1 98GMC1

98GMC1

    Enthusiast

  • Newbie
  • 4 posts

Posted 23 March 2011 - 12:03 AM

Hello, Hopefully someone on here can help me out, I have a 1998 GMC Sierra Extended Cab 4x4 Automatic with a 5.7 Ltr V8...I was getting a p0404 code, now first let me say a New EGR valve was put on about 2 months ago and I was getting codes that o2 Sensors needed replaced so I did that this last weekend then the P0404 code popped up so pulled egr valve and cleaned and cleaned and cleaned, replaced gasket and now getting P0405 code so started searching the web found a site that gave me ways to test the egr ....its at http://easyautodiagn...egr_valve_1.php ok so I followed all the steps:
In step 1 it says to check EGR Pintle Position and you should get a reading between .6 to .9 Volts DC I got .04
In step 2 it says to check the Power 12V and you should get 10 to 12 volts I got 11.6 Volts ..so I am good there
In step 3 it says to check 5 Volt Reference Circuit and says it should register 5 volts ...which mine did ...so good there
In step 4 it says to check verify the ground circuit should read 10 to 12 volts ..mine read 11.6 Volts ...so I am good there
In step 5 it says to check verify EGR SIgnal..says egr to be removed and connected to wiring connector, probe the C Circuit with the red lead and ground the black lead, then push the pintle in and watch for a steady increase in the voltage and that maxiable voltage will not exceed 4.5 and as you release the pintle it should return to your original reading from test on which should be between .6 to .9 volts well aboce you see when I did test 1 I got .04 volts well when I did test 5 and pushed the pintle in it did raise to .07 but no higher and according to the above testing this would mean my EGR Valve is bad.
Am I right from these test that the EGR Valve is bad, would there be any reason a EGR Valve would go bad within 2 months?
Like I siad above only other codes was for O2 Sensors and all those have been replaced and those codes do not show up anymore.
The only other thing I have had to do is replace the Fuel Pump in the tank, which of course once that was done now my Gas needle goes back and forth very very very fast whether vehicle is idling or driving, and from what I have read this could be a ground or a problem with the sending unit, seems like as time goes by the replacement parts get more expensive and less reliable.
Any help form anyone would be greatly appreciated
Have I missed anything? I am just sick of this check engine light and messing with the EGR Valve, I do not want to spend anouther 154 dollars for another one, have thought baout just hitting the junk yard buying about 5 EGR Valves, go to the parts store get 5 gaskets since they are only 2 bucks each and trying each EGR Valve in hopes that one will be good, thanks for reading sorry so long but really need some help with this one
One last thing truck has 182k on it

#2 98GMC1

98GMC1

    Enthusiast

  • Newbie
  • 4 posts

Posted 30 March 2011 - 08:06 PM

Ok well went out and bought another EGR Valve put it on and its been 4 days with no code now so guess a EGR valve can go bad after a couple months , oh well, this part of it is fixed still have the random vibration of the fuel guage


Hello, Hopefully someone on here can help me out, I have a 1998 GMC Sierra Extended Cab 4x4 Automatic with a 5.7 Ltr V8...I was getting a p0404 code, now first let me say a New EGR valve was put on about 2 months ago and I was getting codes that o2 Sensors needed replaced so I did that this last weekend then the P0404 code popped up so pulled egr valve and cleaned and cleaned and cleaned, replaced gasket and now getting P0405 code so started searching the web found a site that gave me ways to test the egr ....its at http://easyautodiagn...egr_valve_1.php ok so I followed all the steps:
In step 1 it says to check EGR Pintle Position and you should get a reading between .6 to .9 Volts DC I got .04
In step 2 it says to check the Power 12V and you should get 10 to 12 volts I got 11.6 Volts ..so I am good there
In step 3 it says to check 5 Volt Reference Circuit and says it should register 5 volts ...which mine did ...so good there
In step 4 it says to check verify the ground circuit should read 10 to 12 volts ..mine read 11.6 Volts ...so I am good there
In step 5 it says to check verify EGR SIgnal..says egr to be removed and connected to wiring connector, probe the C Circuit with the red lead and ground the black lead, then push the pintle in and watch for a steady increase in the voltage and that maxiable voltage will not exceed 4.5 and as you release the pintle it should return to your original reading from test on which should be between .6 to .9 volts well aboce you see when I did test 1 I got .04 volts well when I did test 5 and pushed the pintle in it did raise to .07 but no higher and according to the above testing this would mean my EGR Valve is bad.
Am I right from these test that the EGR Valve is bad, would there be any reason a EGR Valve would go bad within 2 months?
Like I siad above only other codes was for O2 Sensors and all those have been replaced and those codes do not show up anymore.
The only other thing I have had to do is replace the Fuel Pump in the tank, which of course once that was done now my Gas needle goes back and forth very very very fast whether vehicle is idling or driving, and from what I have read this could be a ground or a problem with the sending unit, seems like as time goes by the replacement parts get more expensive and less reliable.
Any help form anyone would be greatly appreciated
Have I missed anything? I am just sick of this check engine light and messing with the EGR Valve, I do not want to spend anouther 154 dollars for another one, have thought baout just hitting the junk yard buying about 5 EGR Valves, go to the parts store get 5 gaskets since they are only 2 bucks each and trying each EGR Valve in hopes that one will be good, thanks for reading sorry so long but really need some help with this one
One last thing truck has 182k on it



#3 hoochi

hoochi

    Enthusiast

  • Member
  • 17 posts

Posted 30 March 2011 - 08:24 PM

Hello, Hopefully someone on here can help me out, I have a 1998 GMC Sierra Extended Cab 4x4 Automatic with a 5.7 Ltr V8...I was getting a p0404 code, now first let me say a New EGR valve was put on about 2 months ago and I was getting codes that o2 Sensors needed replaced so I did that this last weekend then the P0404 code popped up so pulled egr valve and cleaned and cleaned and cleaned, replaced gasket and now getting P0405 code so started searching the web found a site that gave me ways to test the egr ....its at http://easyautodiagn...egr_valve_1.php ok so I followed all the steps:
In step 1 it says to check EGR Pintle Position and you should get a reading between .6 to .9 Volts DC I got .04
In step 2 it says to check the Power 12V and you should get 10 to 12 volts I got 11.6 Volts ..so I am good there
In step 3 it says to check 5 Volt Reference Circuit and says it should register 5 volts ...which mine did ...so good there
In step 4 it says to check verify the ground circuit should read 10 to 12 volts ..mine read 11.6 Volts ...so I am good there
In step 5 it says to check verify EGR SIgnal..says egr to be removed and connected to wiring connector, probe the C Circuit with the red lead and ground the black lead, then push the pintle in and watch for a steady increase in the voltage and that maxiable voltage will not exceed 4.5 and as you release the pintle it should return to your original reading from test on which should be between .6 to .9 volts well aboce you see when I did test 1 I got .04 volts well when I did test 5 and pushed the pintle in it did raise to .07 but no higher and according to the above testing this would mean my EGR Valve is bad.
Am I right from these test that the EGR Valve is bad, would there be any reason a EGR Valve would go bad within 2 months?
Like I siad above only other codes was for O2 Sensors and all those have been replaced and those codes do not show up anymore.
The only other thing I have had to do is replace the Fuel Pump in the tank, which of course once that was done now my Gas needle goes back and forth very very very fast whether vehicle is idling or driving, and from what I have read this could be a ground or a problem with the sending unit, seems like as time goes by the replacement parts get more expensive and less reliable.
Any help form anyone would be greatly appreciated
Have I missed anything? I am just sick of this check engine light and messing with the EGR Valve, I do not want to spend anouther 154 dollars for another one, have thought baout just hitting the junk yard buying about 5 EGR Valves, go to the parts store get 5 gaskets since they are only 2 bucks each and trying each EGR Valve in hopes that one will be good, thanks for reading sorry so long but really need some help with this one
One last thing truck has 182k on it

I had a buddy remove his and clean it with B-12 or sea foam and it worked fine again.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users