Codes P0108 and P1404 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Reply
 
 
 
Thread Tools Search this Thread
Old 05-07-2013, 10:51 AM   #1
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Apr 2013
Posts: 59
Thanked 0 Times in 0 Posts
Wt4Go is on a distinguished road
Default Codes P0108 and P1404

I changed the EGR valve, the Pcv valve and the Map sensor, still throwing the same codes.
2001 Bonneville 3.8
Any ideas?
Jim
Wt4Go is offline   Reply With Quote
Old 05-07-2013, 10:59 AM   #2
Senior Member

True Car Nut
 
2kg4u's Avatar
 
Join Date: Sep 2006
Location: Windsor, Ontario / Detroit, Michigan
Posts: 4,804
Thanked 220 Times in 181 Posts
2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of
Default

https://www.gmforum.com/obd-ii-troub.../p0108-284074/ (follow the link)

P1404 is described as EGR valve pintle stuck open, which in most cases is a false alarm. Possible reason (very likely) for the false P1404 code is that the plastic piston of the EGR valve position instrument (LVDT?) wears over time and starts reading a different position at valve closed than what it was when the EGR valve was first installed. When the car was built and the computer circuits energized for the first time the computer learned the EGR valve closed position signal from the valve position instrument that is built on top of the valve itself. Over time, when the instrument wears, a slightly different signal is sent to the computer and when it differs enough from the 'Valve Closed Signal', that the computer had learned, the trouble code P1404 is set and the 'Service Engine Soon' light comes on.

Replacing the EGR valve with a new one does not necessarily fix this problem because the 'Valve Closed Signal' between valves is slightly different and it is just pure luck if your new valve would give a 'Valve Closed Signal' close enough to your original valve'* signal not to set the trouble code. This is why the new EGR valve 'Valve Closed Signal' must be re-learned by the computer.

So, what this all means is that if the P1404 is a false code meaning that the valve pintle is not stuck open, then new 'Valve Closed Signal' can be re-learned by the computer using the old valve.

The fix goes like this:

1. Disconnect the wire harness from the EGR valve.

2. Turn key ON and erase the trouble code(*) from the car'* computer AND TURN KEY OFF IMMEDIATELY WHEN THE SCANNER SAYS CODES HAVE BEEN ERASED. DO NOT TURN KEY ON BEFORE YOU RE-CONNECT EGR WIRE HARNESS.

3. Re-connect EGR wire harness and your problem should be fixed.

I believe erasing codes with wire harness disconnected and turning the key OFF right after P1404 code has been erased re-sets the 'Valve Close Position' reading in the computer and triggers computer to re-learn position next time the key is turned ON.
2kg4u is offline   Reply With Quote
Old 05-07-2013, 11:17 AM   #3
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Apr 2013
Posts: 59
Thanked 0 Times in 0 Posts
Wt4Go is on a distinguished road
Default

Thank you I will try this when I get home tonight.
Wt4Go is offline   Reply With Quote
Old 05-13-2013, 10:41 AM   #4
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Apr 2013
Posts: 59
Thanked 0 Times in 0 Posts
Wt4Go is on a distinguished road
Default

Thank you 2kg4u. I did as you suggested and reset the computer for the egr valve and it cleared both codes. I have driven over a hundred miles and passed my emission test and no codes have reset. Thank you
Jim
Wt4Go is offline   Reply With Quote
Old 05-13-2013, 12:51 PM   #5
Senior Member

True Car Nut
 
2kg4u's Avatar
 
Join Date: Sep 2006
Location: Windsor, Ontario / Detroit, Michigan
Posts: 4,804
Thanked 220 Times in 181 Posts
2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of2kg4u has much to be proud of
Default

I'm certainly glad it worked for you. My favorite fixes are the free ones.
2kg4u is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
P0404 and P1404 and lots of noise... mdbonnie 2000-2005 5 03-08-2012 08:23 PM
Codes P0107, P0108, P0121 on 1997 Park Avenue dieselyj1 1992-1999 2 12-01-2011 10:30 PM
Code P304 and P1404 Anything4APontiac 1992-1999 5 04-28-2010 06:29 AM
1997 Bonneville with error codes P0121 and P0108 Ws10drf 1992-1999 6 02-05-2009 12:25 AM
P1404 and P0336 even with known good EGR valve Hans 2000-2005 9 01-29-2007 12:40 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 07:21 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.