1996 Nissan Maxima - P0325

I've got a 1996 Nissan Maxima with 126K miles. It's been running fine all it's life. My sister has been driving it for the last 2K miles, and just reported the following to me. I've only driven it a few miles since she told me about this, and I haven't been able to recreate the problem. Here's what she told me.

Recently, regardless of whether it's under load (uphill) or just driving in town on the flats, sometimes it won't have enough power, and even if she presses the gas pedal more, it won't get enough power until she floors it, and then the power comes back, and she can back off of the gas. She doesn't hear any knocking.

Like I said, I drove it for about 20 miles today, uphill and on flats, and I couldn't get it to reproduce the problem.

I used a scanner and got code P0325, which is the knock sensor. The Check Engine Light has not been on at all, though. I guess this doesn't always throw a code. The scanner also showed knock sensor circuit malfunction. I don't know if this means the knock sensor is malfunctioning, or if it is functioning correctly, and senses a knocking condition in the car. Can anyone tell me? Again, my sister says she doesn't hear any knocking sound when the power is lacking.

This is my first post here. I hope I've explained myself ok.

Oh, and if it is the knock sensor, is this an easy replacement for me? I am fairly mechanical (oil, brakes, tune-ups, etc.)

Thanks,
Shannon

The knock sensor code is common on the 96 Maxima as well as other years. It will store a code, but it will not turn on the check engine light. If you have the correct tools you could most likely change the part yourself. It's located under the intake manifold and is bolted to the top/center of the engine block. It is visible if you look under the intake manifold from the drivers side of the car. I have NOT run into a problem like yours which was caused by the knock sensor.

One of the common items that I have run into on the 96 Maxima, which could cause the lack of power condition that you described, is a dirty air flow meter sensor wire. There are many other items as well, but the air flow meter is something I've seen on many occasions. In most cases it did not set a code. If you want to try something on speculation you could remove the air flow meter from the car and spray the sensor wire with some air flow sensor cleaner. I use a product made by CRC, it should be available from your local auto parts store. It may not solve the problem, but it won't hurt to try it.

Sometimes the cleaning will solve the problem, but on several occasions I had to install a new airflow meter because the car just didn't run 100% after the cleaning procedure.

Without any other information, that is the best advise I can give you at this time.

Good Luck,
Let us know how you make out.

Hey, thanks for the reply.

I think the first thing I might do is to do the 120K miles tune up. Actually, things like plugs, PCV, ignition wires, fuel filter, etc. have never been changed because it's always run great. What's been done on a regular basis is oil and filter every 4K miles. The air filter has been changed whenever it looked too dirty to clean. I'll then clear the P0325 code, and also drive for a while to see if either the code or the road (lack of power) problem comes back.

If the problem comes back, I'll then try to find the knock sensor, and determine if I'm able to replace it myself. By the way, if I do replace it, is it best to get a dealer part, or is any aftermarket replacent ok?

About the air flow sensor meter wire...first, where is it located? I have no idea. Second, when you say 'wire' could be dirty, do you mean the where the wires plug into the sensor? (I assume it plugs in.)

I will write back with what I've done and the results.

Thanks again.

Shannon

I'll try to keep it as simple as possible. The air flow meter assy. is bolted to the top air cleaner cover and is also connected to the air intake hose.. The wire I'm talking about is in the air flow meter housing not the wiring connector on the outside of the housing. If you look into the opening of the air flow meter housing (after you remove it from the car) you will see the sensor wire that I'm indicating.

I would suggest that you do a google search to help you locate and understand the airflow meter better. There must be a site that will provide that info for you. Check the location of the knock sensor as well.

As far as the tune up goes, make sure you use NGK spark plugs as I have seen problems when using other brands. Your engine does not use spark plug wires because it has a coil on plug system. One ignition coil for each cylinder mounted directly over the spark plug. There is a replaceable fuel filter and PCV.

You may want to consider a 1 year subscription to Alldata which has a wealth of information. I think it is $25 yr for one model of vehicle. Well worth the $$

you can generate knock sensor dtcs if the car is misfiring occasionally which at 120 000 miles with the original plugs it probably is a bit!

I googled and found these informative sites:

http://tinyurl.com/ywffz5

http://tinyurl.com/23tbva

http://www.autozone.com/shopping/repairGuide.htm


I'm off to the parts store for plugs.

Shannon

Jeff.
Never heard of a misfire causing a knock sensor code. If there was a misfire there should be a misfire code, wouldn't you think? I've had lots of cars with a misfire code, but never with a knock sensor code unless the knock sensor or wiring was faulty.

What have you noticed that I'm missing?

Good question, and just to be clear, for all that are reading this thread, I got a P0325 code, no MIL, and no misfire code. I do get a loss of power on occassion.

Shannon

Ok. I've replaced the plugs, using the original NGK platinums that were in there for the last 126K miles and served me well. I was surprised (and happy) to see that all the old plugs were in very good shape. They only had a slight light tan coloring on the tips. All looked exactly the same. The gaps had not enlarged, and no fouling or oil deposits.

BTW, I still haven't experienced the lack of power for myself. Only my sister has reported it to me.

I now am going to clean the knock sensor grounding wires, and the air flow meter sensor wire (per chasr212r), now that I have found where both are located.

Then, I'll use the scanner to erase the P0325 code, and drive the car for a while, and see if the code comes back. I think, but I'm not sure, that if the code comes back, but I haven't experienced a lack of power, this may mean that the knock sensor is bad, or it's connection is bad.

Shannon.

I agree that it's unlikely the Knock sensor is causing a power complaint unless it's telling the pcm to change the timing when it shouldn't be and it's now acting like it's out of time. I know it's a common code for nissans, maybe check for any tsbs for your car and that code.

chasr212r - so, you mean if i have p0325 and p0136 codes that appears. it means the only problem i have is p0136 chasr212r? please do reply to this question

A knock sensor code will not turn on the check engine light on a nissan. If you scan a medium to high mileage nissan 7 of 10 will have a P0325. So just go after the code to correct the light.

thank you for the reply. so, what makes the p0136 appear? and what triggers it? and how will i fix the problem? and if i did fix it will p0325 wont appear anymore?

The code is for the rear O2 voltage high. Most of the time is a bad O2 but you need data from a scan tool to verify, and yes the knock sensor code probably will come back if you do not replace the knock sensor but it will not turn the check engine light on if this is the ONLY code in the pcm.