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David.C, Nissan Technician
Category: Nissan
Satisfied Customers: 83
Experience:  ASE master technician,nissan factory certified master technician,hybrid cetified,GTR certified
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1997 Nissan Altima: pass smog..OBD II Codes showing P0325 and p100

Customer Question

1997 Nissan Altima GXE. Didn't pass smog due to engine light. OBD II Codes showing P0325 and P1400. Replaced the knock sensor and egr valve and took it to smog test site. They cleared the engine light and was told to drive for 15-20 miles. Drove for 20 miles both on street and freeway, and engine light never came on. Went back to smog test site and checked the coding, and was told that knock sensor still giving out code, and was told to drive some more. As soon as I left the site, the engine light came on again. Is there anything else I can do, without spending any more money?
Submitted: 8 years ago.
Category: Nissan
Expert:  David.C replied 8 years ago.

hi brand

can i what engine and which codes remained

Customer: replied 8 years ago.

Engine: 4cyl 2.4L FI

the guy who checked the codes said "the knock sensor is still showing, and the engine light might turn on again, so drive it some more".

as soon as I drove it off, the engine light came back on.


Expert:  David.C replied 8 years ago.


see if i can give you enough info to do this yourself

well first p1400 isnt egr valve itself its the soleniod and you can basically test it with acar battery to see if its operating,see illustration (all illustrations will be at the end)

also for the knock sensorcheck for frayed wiring and make sure both grounds(F17 and F31 see illustrations)


when you test egr soleniod -powered up you will here and or feel a click


ok do this first and hopefully you will find your issue easily



David.C and 3 other Nissan Specialists are ready to help you
Customer: replied 8 years ago.

oh man, does that mean that egr valve may not have needed replacement?

when i initially checked online for what the code P1400, it showed EGRC Solenoid Valve, but when i went to Kragen, the sold me the egr valve and stated it's basically the same thing.

also, i'm curious as to when the guy checked the coding again, it only showed the knock sensor as still being an issue.

should i just take it to a mechanic?

Expert:  David.C replied 8 years ago.

sorry to say its not the same thing

and may require more than i drive cycle to set

and on the knock sensor alot of times you will find its a bad ground or wiring

check the soleniod like i said if its bad you can probably find one in a salvage yard

let me know how it goes