# Urgent help needed: Nissan Maxima 1998 SE



## rdhing (Jun 1, 2005)

Hello all Nissan Maxima enthusiast and gurus...my Check Engine Light recently came on. Based on reading from AutoZone, two codes, P0325 & P1448, were displayed on the reading system. P0325 is for Knock Sensor and P1448 is for Emission. The Autozone person told me Knock sensor problem tend to decrease gas mileage and I have seen my gas mileage decrease as well. However for now I have reset the check engine light and hoping for it not to show up again. However if it does, what should the plan of action be? Is it something I can do myself, that is buy a knock sensor and replace or do I have to go to a dealer ( this is worst case scenario). 

However, I would like someone to give me advice. I am on a tight budget and every penny I save based on valuable advice would be helpful.

Thank you,


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## brianw (Feb 25, 2004)

The `98 Factory Service Manual says probable causes for P1448:
- EVAP canister vent control valve
- EVAP control pressure sensor
- Blocked rubber tube to EVAP canister vent control valve
- Water separator
- EVAP canister is saturated with water
- Vacuum cut valve

So, check the EVAP system for damage and blockage.

Fix that, then drive it around and see if the codes comes back. A bad knock sensor or knock sensor wiring harness (generally smart to replace both at the same time) is somewhat common, but I have found that KS codes are often thrown along with other codes, and disappear when the cause of the other code is fixed...

www.motorvate.ca has instructions on KS replacement. Not sure about the EVAP, it's definitely possible to inspect it yourself but I haven't had to troubleshoot it before so I can't say how difficult it is.


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## sapo (Jun 14, 2005)

rdhing said:


> Hello all Nissan Maxima enthusiast and gurus...my Check Engine Light recently came on. Based on reading from AutoZone, two codes, P0325 & P1448, were displayed on the reading system. P0325 is for Knock Sensor and P1448 is for Emission. The Autozone person told me Knock sensor problem tend to decrease gas mileage and I have seen my gas mileage decrease as well. However for now I have reset the check engine light and hoping for it not to show up again. However if it does, what should the plan of action be? Is it something I can do myself, that is buy a knock sensor and replace or do I have to go to a dealer ( this is worst case scenario).
> 
> However, I would like someone to give me advice. I am on a tight budget and every penny I save based on valuable advice would be helpful.
> 
> Thank you,


A Knock sensor code will not turn the check engine light on.

As far as the code for the evap system is concerned, start by making sure your gas cap is on tight /listen for the clikcs/

Furthermore, check for stuck vent control valve. It is located on the carbon canister. unbolt it, and apply b+ to one side and ground to other yyou should hear sharp clunking for on and off.

sapo


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## MDeezy (Aug 7, 2004)

the KS code may show up and may not. Best way to know for sure if to pull codes with an OBD-II reader. I've seen my brothers Max throw a KS code, and I've heard it never shows up until you use a code reader.


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