P0400 code
Thread Starter
Launching!
Joined: Jul 2014
Posts: 216
Likes: 0
From: Las Vegas, Nevada
P0400 code I have a 96 Trans Am & I have the SES light for the P0400 for the EGR valve. Prior to posting this that I was reading that if you buy block off plates it will cure the problem. My question is if I buy them & install them is it a really a guaranteed fix just for this code???
More information needed:
Is your engine stock / mostly stock or modified (head work, larger cam with more overlap than stock, etc., can it do without EGR?)
If your engine is stock, with EGR non functional it will have slightly elevated combustion temperatures and oxides of Nitrogen ("NOX" on your emissions) will be higher. This is a concern if you have to pass tailpipe emissions. P0400 indicates "low EGR flow" due to clogging or damage to the vacuum lines or the EGR solenoid no longer working.
If you simply remove the EGR from a stock engine and exhaust and cap it off, the PCM still sees the problem ("low flow" becomes "no flow"). To properly delete EGR, you'll have to cap off the exhaust line to the manifold or header, though most EGR blockoff kits include this piece (but not all). Also, the code will still set unless it is tuned out of the PCM.
Options:
If stock -> diagnose and fix it
If appropriately modded -> delete it and tune it out
Is your engine stock / mostly stock or modified (head work, larger cam with more overlap than stock, etc., can it do without EGR?)
If your engine is stock, with EGR non functional it will have slightly elevated combustion temperatures and oxides of Nitrogen ("NOX" on your emissions) will be higher. This is a concern if you have to pass tailpipe emissions. P0400 indicates "low EGR flow" due to clogging or damage to the vacuum lines or the EGR solenoid no longer working.
If you simply remove the EGR from a stock engine and exhaust and cap it off, the PCM still sees the problem ("low flow" becomes "no flow"). To properly delete EGR, you'll have to cap off the exhaust line to the manifold or header, though most EGR blockoff kits include this piece (but not all). Also, the code will still set unless it is tuned out of the PCM.
Options:
If stock -> diagnose and fix it
If appropriately modded -> delete it and tune it out
TECH Veteran
Joined: Dec 2008
Posts: 4,147
Likes: 62
From: Little Rock, AR
I have a 96 Trans Am & I have the SES light for the P0400 for the EGR valve. Prior to posting this that I was reading that if you buy block off plates it will cure the problem. My question is if I buy them & install them is it a really a guaranteed fix just for this code???
Post #2 has good advice.
Thread Starter
Launching!
Joined: Jul 2014
Posts: 216
Likes: 0
From: Las Vegas, Nevada
My car for the most part stock. Only mods done to it is a CAI & Muffler Delete. I have not noticed any difference in performance nor regular street or highway driving at all what's so ever.
Thread Starter
Launching!
Joined: Jul 2014
Posts: 216
Likes: 0
From: Las Vegas, Nevada
For emissions purposes in Las Vegas of course all they do with my car is run the OBDII into the OBDII port and just wait for all monitors to be checked along with everything else. (It's doing this while it's reaching a 100% on the computer. They don't do a visual emissions test or the sniffer.)
