Finally got around to manually checking the CEL codes today, after almost two months.
-P1400 EGRC solenoid valve
-P0325 Knock sensor
-P1447 EVAP purge flow monitoring
I have no clue about a egrc solenoid valve or a knock sensor, I've just never had to work with those things before. I'm gonna assume the evap control system code is from having a cat delete, and possibly an exhaust leak. Any words of advice or suggestions would be appreciated. Thank you

 

You might have a blocked egr system. You need a knock sensor. If you do a search on this forum or on you tube you will find the answers. These are common codes

 

Pull the egrc solenoid, hotwire it to the battery, and stick a piece of hose on it to blow into. It should click, and it should be able to stop air flow. If not, replace it.

Evap purge flow monitoring, IDK, could be blocked or broken Bose or a bad sensor. There is a sensor that measures vacuum back by the charcoal canister, but I don't think that's it.

Also pull the hoses off the charcoal canister and check for loose bits of charcoal. These canisters are none for breaking up will block lines and cause the sloenoids to hang open.

The KS code is probably a ghost, Maximas will throw up a KS code in the presence of any other emissions code. Fix the other two first.

Download the service manual from my signature below, there are descriptions of all the DTCs, and diagnosis procedures for them as well.

 

https://maxima.org/forums/4th-genera...html?styleid=2

That is where it is located. I changed mine out 2 years ago. It was relatively easy, expect some blood though haha. I did not notice a difference in mpg or acceleration. It simply got rid of the code.

If your looking to get rid of a quick code I'd start with this. If your looking to get more performance back/mpg I'd replace the knock sensor first

 

You would be wasting money. The KS code will not go away until all the other codes are fixed and cleared.

 

Replacing the knock sensor first might not clear the code until the other codes are fixed. The car would run better though.

 

At this point a KS code does not necessarily mean the KS is bad. Replacing a good KS with a phoney code will not make him run better. Fix the other stuff first to determine whether the KS code is legit.

 

Asand1, I thought, perhaps incorrectly, that the computer would recognize that it is attached to a functioning knock sensor, then clear the code. Other sensors eventually clear the codes, so why would a knock sensor be any different? I'm just trying to learn and understand.

 

As I already posted, and any other ORGer should know, the 4th gen has a quirk where in the presence any emmisions code the ecu will also post a false KS code. There are endless posts about it. ALWAYS fix the other codes before addressing KS codes.