Hi there guys of mazdaforum.com. Long time reader, first time poster. I post alot over at mazdaworld.org as well, but figured I would put this one to your brains as well

Got in the Millenia again yesterday, started her up, got about a mile down the road and the CEL came on. I didn't notice any loss of power, anything out of the ordinary, no smoking, no knocking, no "chugging" or hesistation. This morning I took it to AutoZone and they hooked up the ODB II reader and pulled code: P0325 "Bank 1 of Sensor 1 - Knock Sensor" was the error. I confirmed it was the same error as posted here in the ODB II code list after doing a search. All of the other threads I searched for with P0325 in it never had a resolution or other suggestion what could have been wrong other than replacing the knock sensor in the 2.5L engine. Too bad I have the 2.3L Miller engine in my 96 S.

I popped the hood when I got back and let the engine run for awhile and noticed a soft clicking noise that I had not heard before which seemed to be coming from the first bank of spark plugs underneath the front intercooler. Could the knock sensor be telling me there is another problem possibly? Like bad spark plugs, coil pack, etc.? I just got both serpentine belts replaced last week and so far it had been fine. It was also time for an oil change ( which I did myself ) and I added a bottle of Chevron Techron to the gas tank and filled her up. I just mention those since they were the most recent thigns I did to the car.

I'm not looking for a definitive answer as I am no mechanic or wrench myself. Just looking to see if anyone else has had a problem like this and what their fix was (my search results for similar problems didnt seem to yeild much). As always guys thanks in advance!!! Sorry for always asking questions.

-Hadrien

 

Code and faulty sensor is common on 2.5l as you said but not on the 2.3l. Sensor signal voltage is checked by the engine computer when turning the key to 'run'. Does the code return after being cleared from memory. If so there is a fairly easy way to test the sensor itself and will only require removing the plastic upper engine cover and using a digital ohmmeter available from radio shack for $10.

 

The sensor is definately bad I was told. Taking it Monday to get repaired as well as have them most likely replace the spark plugs, and timing belt since they will be that far in anyway. Thanks for the tips though!

 

Hope you check this again before you take the car in. The spark plugs would be a very good idea during the knock sensor replacement but there is very little ( talking 4 timing cover bolts)that over lap for replacing the timing belt. Instead of the timing belt I would consider having the valve clearance adjustment checked. The shop will be right there with the entire intake off already and will save you a lot more now then doing it down the road when they will have to pull it all off again. Give it a thought and talk to the shop first.
I also found this which related to install of you knock sensor. Make sure the shop reads it and gets the appropriate sensor.
Check Engine Light may illuminate with code P0325 stored in memory. Thisconcern may be the result of water entry into the knock sensor causing abnormal electrical resistance. To prevent this concern, the sealing process of the sensor was improved on September 2, 1998. We also suggest that the knock sensor harness is disconnected from the bracket before removing the intake manifold N lysholm compressor to avoid possible damage. NOTE: When removing the knock sensor, use SST 49 H018 001. 1. Verify customer concern. 2. If the knock sensor is found damaged, replace with new part. Refer to Workshop Manual for removal/installation procedures. 3. Verify new part is modified by checking production code. 1st digit = YR. (i.e. 8=98, 9=99, etc.) 2nd digit = MO. (i.e. A=Jan, B=Feb, etc.) 3rd N 4th digits = day of the month Note: Modified parts have code of 8H28 and later. PARTS INFORMATION: Knock Sensor - KJ01-18-921A Note: Remember to order and install a new intake manifold gasket during knock sensor replacement.

 

Wow thanks for the awesome info babyhuey! I will most certainly mention this to the mechanic. Oddly enough , the CEL came on a few hours after I had given the old Millenia a good detailing and washing. I cant really imagine but maybe the spray washer some how forced water into the knock sensor area and helped caused the CEL? It most likely a coincidence but ya never know. Thanks again though!

EDIT: I forgot to mention that since the CEL came on last Saturday, 3 times now I have been leaving work and the car bucked a little and didn't seem to want to shift. Once she was on the road for a few minutes, all was well, but power also seems to be lacking a little overall. I have had a friend follow me home the last few days and at varying speeds and levels of throttle he has not seen any smoke or anything coming from the tailpipes at any time. I mention this since I know the superchargers are a problem on the 2.3Miller Cycle engines with the Supercharger, which many times seems to be a cause of smoke (according to many over at mazdaworld.org)

 

Heard back from the mechanics today. Looks like the knock sensor is totally dead, the resistance check on it failed. Quoted me $930 for a new knock sensor, all new seals for the intake manifold, all around the supercharger, etc. (Basically every seal that you ahve to take off to get to the knock sensor) , and new spark plugs.

Also had them check to make sure it did not need a Valve Adjustment while they were in there, he said it looked good but will double check. When I asked if they saw any oil in the intercoolers and supercharger he said not that he could see and will inspect further to make sure. It sounds like alot of cash I guess, but I know its ALOT of service time. Just wanted to update the thread.

 

Well here is the finally total for my knock sensor replacement + a few other things. I mentioned the Valve Adjustments to the mechanic but he didnt seem to think it needed it. Now that I think about it should have insisted due to the fact that just checking means they would have replaced the valve cover gaskets as well. I told them if they found any oil in the spark plug wells or supercharger to PLEASE let me know and they said they didn't see oil in either which made me feel a little better. Anywho here is the part list and prices for everything.

Qty Part Number Description Each Price (total)
------------------------------------------------------------------
6 ZFR5F11 Spark Plug 4.15 24.90
2 KJ01-13-111 Intake Gasket 14.00 28.00
1 KJ01-13-203 Seal 14.00 14.00
2 KJ01-13-234 Air Intake Gasket 6.92 13.84
2 KJ01-13-555 Seal 12.03 24.06
1 KJ01-13-A66 Gasket 26.42 26.42
1 KJ01-13-S02 Air Intake Gasket 8.92 8.92
1 KJ01-13-VJ8 O-Ring 4.92 4.92
1 KJ01-18-921A Knock Sensor 159.48 159.48
1 KJ01-20-255 Gasket 7.08 7.08
1 KJ01-20-306A Gasket 8.33 8.33
1 KJ01-20-849 Air Intake Gasket 8.50 8.50
1 KJ01-20-859 Air Intake Gasket 8.50 8.50
2 KJ02-13-234 Air Intake Gasket 9.00 9.00
.5 ANT Antifreeze 8.50 8.50
1 LOF Oil Change & Filt 27.99 27.99
1 EPA Environmental Fee 3.00 3.00
LABOR LABOR 532.00

---------------------------------------------------------------------------
TOTAL: 922.19
TAX: 23.23
GRAND TOTAL: 945.42


So there you have it, I am sure I added stuff you guys dont care about in there, but I just copied my bill as it was to show all the parts they used. Hope it can help someone in the future with a Knock Sensor replacement on the Millenia S. Thanks again for all the help.

EDIT: DOH IT DIDNT KEEP MY SPACING, SORRY!

 

Well it looks like the mechanics put the wrong spark plugs in. They put the NKG plugs in for the Millenia L with the 2.5L engine and not for my 96 Millenia S with the 2.3L engine. The car seemed fine until last night and today. I could barely get her down the road today and the CEL came on and then started to blink. I pulled over and shut the car off since I have heard a blinking CEL is bad news. Let the car sit a minute and started her back up, the CEL came back on but was solid. The car ran a "little" better so I was at least able to get it home.

I am going to try to limp her to the mechanics tomorrow so I can get the right plugs. I found out the put the wrong plugs in before I started to have problems and was apprehensive to take the car back, but now I have ZERO problems taking the car back for service. I don't mind paying the price difference for the better plugs but I hope they don't want me to pay for service as well. Thanks again to babyhuey for all the awesome info. I will keep the thread updated here as well as mazdaworld.org.

 

Well it looks like I had a misfire on cylinder #2. They had the car for most of the day and insisted on the fact that those were the right plugs after much discussion with all of the mechanics and the owner. They said to drive it a few days and if I want to put the Platinum plugs in that they would do it for me.

Today I went to Advance Auto Parts and ordered 6 of these:

http://www.partsamerica.com/ProductD...pe=960&ptset=A

NOTE: You may have to input your ZIP to see the complete link

According to everything babyhuey said and what the manual said , these should be the right plugs. I am going to call the mechanic back tomorrow, tell them the car still doesn't feel right and that I will be bringing the plugs to put in. If the plugs I ordered are STILL the wrong ones , send me a PM, email, or post here and I am sure Advance Auto Parts will take them back. I just like giving the part I know is good to the mechanic.

They were trying to tell me that the reason the gap is different on the plugs they put in versus the one Mazda has in the manual was because the one Mazda specs for the S is a Platinum plug and the gap has to be different because of the fact that it is platinum. Sounded a little fishy to me and my friend that went along as backup.

I have been in the Computer service industry for a few years and dont like it when people tell me how to do my job, esp when I think I am right, so I dont want to be that "*******" that doesnt know TONS about cars but insists that he is right when I go in asking them to change the plugs again. If they want to charge me to do the work I guess I will be taking my first attempt with my friends at changing the plugs in my 96 Millenia S. Thanks again for all the tips guys.

 

Thanks for the info post - this forum has been extremely helpful. My Millenia has the P0325 code as well. Will check the resistance on the sensor in the morning. The mention of water is funny - I had powerwashed (1500psi - electric version) the outside of the engine to clean off the goo left over from an engine overhaul and the CEL came on - wonder if the water had something to do with it as well... Hoping not to have to replace the sensor as it means removing the intake manifold.......