What might cause codes p0325 , p0304 to turn my check engine light on during smog test on my1998 Nissan Altima 2.4L No kicking No noise except the drive belt which just started after smog test

If the code is p0325, it should be repaired, HOWEVER, on nissan products from 1996 to 2002, a p0325 does NOT illuminate the check-engine lamp. Knock sensor on that vehicle is for PING control not for emissions reduction. On other vehicles (say a chevy with a p0325) it WILL light the check engine lamp which is an automatic smog fail.

Check engine light on ? What happened before the problem happened?

p0171 = fuel system too lean, this means vacuum leak or faulty oxygen sensor

p0303 = cylinder 3 misfire

p0325 = knock sensor malfunction.

p0303 and p0325 - i can see these working together, if a cylinder misfires, it will cause the knock sensor to trip. I would lean towards the coil and or ignition module, along with a faulty oxygen sensor.

Hi Candy,here's a link to the P0171 code.Here's the code P0325. O n the Code P0171.it says it will have a

• detonation (spark knock) which,the first code is causing the second code to go off.

Robert, High emissions usually mean the EGR valve and several hoses and other smog components are clogged up. There is no easy fix, you have to get the shop to check through the smog system on your car if you cannot do it yourself. Type of driving, short runs, high miles, burning oil etc all contribute to the engine giving a dirty reading. It may not be enough to light the lamp but it'll be dirty enough. Of cause, it may be the lamp is bust as well? Does it test light when you start up?

OK THIS A SITUATION. THE P0100 IS A MASS AIR FLOW PROBLEM. THE P0325 IS A KNOCK SENSOR MALFUNCTION. AND THE P0733 IS A TRANSMISSION ISSUE. I DONT KNOW IF U HAVE A TRUST WORTHY MECHANIC BUT FOR THESE THREE FIXES U NEED ONE ESPECIALLY IF U ARE NOT CAPABLE OF THIS WORK. THESE PROBLEMS WILL CAUSE U POOR PERFORMANCE AND A HEADACHE. THESE PROBLEMS DEFINITELY NEED TO BE HANDLED ASAP!

p0304 misfire on cylinder #4
p0325 knock sensor circuit

Could be a bad wire, plug, or coil pack on cylinder #4 (or bad distributor connection).

Knock sensor indicates a knock coming from the engine, perhaps from cylinder #4.

This may lead to a diagnosis if you change parts related to cylinder #4.

Good luck.

p0325 is, ignition system or misfire, could be plugs, wires, or a bad coil. p1126 throttle control motor relay curcuit open.P1126 Power supply for the throttle control motor is provided to the ECM via throttle control motor relay. The throttle control motor relay is ON/OFF controlled by the ECM. When the ignition switch is turned ON, the ECM sends an ON signal to throttle control motor relay and battery voltage is provided to the ECM. When the ignition switch is turned OFF, the ECM sends an OFF signal to throttle control motor relay and battery voltage is not provided to the ECM. possible cause, Harness or connectors (Throttle control motor relay circuit is open Throttle control motor relay.

Nissan code:
P1444 Canister Purge Volume Control Solenoid Valve

Generic OBD II code:
DTC Codes - P0300-P0399 – Ignition System or Misfire
P0325 Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)

I hopes this helps you.
Replace or fix these two items should do the trick.
It's hard to diagnose a car over a computer.

Nita0605 you should have included a little more infomation. Does the car drive any different when the light is on? Most likely you have a trouble code P0325.........Knock sensor fault or O2 sensor problem. I wouldn't worry about it until the light stays on