Diagnostic code P0400

DWRIGHT956

MEMBER
1997 NISSAN TRUCK
4 CYL
2WD
MANUAL
178,000 MILES

"Exhaust gas recirculation flow malfunction". What causes it and how can you fix it.

Wednesday, December 2nd, 2009 AT 1:18 AM

4 Replies

BLUELIGHTNIN6

MECHANIC
16,542 POSTS

Hello,

This happens when the EGR valve fails or the passages get clogged up and need to be cleaned out here is a video that shows how to check the valve and the location of the valve below.

https://youtu.be/DqUCbbKdWf4

Check out the diagrams (Below). Please let us know what happens.

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Wednesday, December 2nd, 2009 AT 1:23 AM

ENESHAD

MEMBER
1 POST

I had this problem got a new EGR for $98.00 all fixed I love this site.

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Thursday, July 18th, 2019 AT 12:38 PM

MSANN

MEMBER
1 POST
1996 NISSAN TRUCK
6 CYL
FWD
AUTOMATIC
127,677 MILES

Po400/po446 problems what does this means and can I make the reparts myself. Or how costly will it be.

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Thursday, July 18th, 2019 AT 12:38 PM (Merged)

KHLOW2008

MECHANIC
41,815 POSTS

Hi MSANN,

P0400 = Exhaust Gas Recirculation flow. Most probably the EGR passage is clogged. You need to clear it of carbon deposits.

P0446 = Evaporative Emission Control System vent control.

Not easy to handle yourself and the cost depends on any replacement parts needed.

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Thursday, July 18th, 2019 AT 12:38 PM (Merged)