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PO400 Fault Diagnosis for 2000 Nissan Frontier 2.4L - EGR-Related Solutions

Model: Nissan Frontier Fault Code: P0400 Posted: 2012-06-24 21:57

My hand-held Actron scanner is detecting code PO400 on my 2000 Nissan Frontier 2.4L, but it lists over ten potential fixes—ranging from vacuum line cleaning to EGR cleaning or PCV valve replacement. I'm looking for a more focused and reliable diagnosis to save time, money, and avoid unnecessary frustration. If anyone has successfully resolved this issue on the same model, please share a targeted troubleshooting approach based on actual experience. Thank you, Don.

Related fault codes
P0400
Comments (1)
Anonymous 2012-06-26 08:48

The PO400 code is most commonly related to EGR system issues. 1) Check if the EGR valve is operating properly—ensuring it opens and closes correctly. 2) Inspect EGR flow: verify that the EGR ports and passages are not restricted. There is a known Technical Service Bulletin (TSB) regarding EGR passage restriction, which is mentioned above. However, this issue still requires proper diagnosis to confirm.