p0325 code need help...

[Illicitdream]

I was driving down the highway at 75 mph and my check engine light came on. Got home and pulled the code. p0325 (circuit 1) Knock sensor... Everything I have read and researched people say that most of the time the wiring harness and/or sensor(s) is going or has gone bad. I don't want to just throw money and replace parts if that's not the case. I have read plenty of threads on the p0330 , but not many on p0325 are out there. Should I just replace the sensors and wiring harness? Also I know that need to replace intake gaskets since it seems that I will be pulling the upper intake manifold off in order to access this. Also does anyone have the write up on how to replace these sensors and wiring harness? Any things I should be careful and to watch for while replacing these parts? Thanks in advance.

 

[4Runnermex]

I've done a few and learned to do all while I'm there.
I find it easier to remove all wiring harness just let hang by the firewall.

Let give it a run..
1. Disconnect battery
2. Disconnect all harness from tranny pull it up to engine bay.
3. Remove air intake hose
4. Throttle cable or cables 96-00 3 01-02 1
5. Remove top radiator hose
6. Unbolt timing cover and remove
7. Top air intake 6 bolts
8. Disconnect water lines and harness to the throttle body
9. Disconnect fuel pressure regulator vacuum hose
10.Remove black bracket that hold trans cable with a 12Mm
11. Unbolt fuel lines from intake (2 10MM)
12. Unbolt harnes from back of lower intake 1 ea 10Mm bolt
13. Remove lower air intake 5 bolts
14. Disconnect complete engine harness and set aside by firewall
15. Disconnect heater hoses going into heater core.
15. Remove complete lower intake 4 nuts 6 bolts 12Mm(don't disconnect fuel line pull completely
Also 2 small 12mm bolts towards the front on the engine.
16. Clean area really good from old gasket
17. Remove knock sensor 27mm off set wrench works
18. NEW WRING HARNESS

Repeat all backwards for install. Watch the harness doesn't get pinched. There's a small are on the lower on the where it seats without being pinched.

 

[4Runnermex]

 

[Rock_Rat]

I was driving down the highway at 75 mph and my check engine light came on. Got home and pulled the code. p0325 (circuit 1) Knock sensor... Everything I have read and researched people say that most of the time the wiring harness and/or sensor(s) is going or has gone bad. I don't want to just throw money and replace parts if that's not the case. I have read plenty of threads on the p0330 , but not many on p0325 are out there. Should I just replace the sensors and wiring harness? Also I know that need to replace intake gaskets since it seems that I will be pulling the upper intake manifold off in order to access this. Also does anyone have the write up on how to replace these sensors and wiring harness? Any things I should be careful and to watch for while replacing these parts? Thanks in advance.

A 0325 code is the same as the 0330 code. It's the other bank. ONLY use OEM Sensors. Repeat, ONLY use OEM sensors. You can try to reset it for as long as you can. I went almost a year clearing the code. Four hour job. Do both sensors. You don't want to go back in there again.

Take a ton of pics for reference, tape up ALL possible holes, and like [MENTION=127012]4Runnermex[/MENTION] said there's a very small channel for the sub harness to run through under the manifold. DON'T pinch your harness after it's all together. Felpro gaskets go on dry. Sensors and harness go in dry. Don't use dielecrtic grease. Sensor torque 29ft lbs.

Dont hesitate to ask questions.

http://www.toyota-4runner.org/3rd-gen-t4rs/184979-knock-sensor-0330-everything-replaced-puzzled.html

 

[Rock_Rat]

Just remembered [MENTION=120313]BlackRustBucket[/MENTION] put together some pretty good DIY pics back in April. Check out his thread.

http://www.toyota-4runner.org/3rd-gen-t4rs/194340-knock-sensors-harness-diy.html

 

[Illicitdream]

You guys are awesome thanks. Last question though, what are the part numbers...? I have found 89615-12040 & 12090 that both say the fit the 5vz... And also what about the harness... Is it 82219-34010? And I have learned to always go oem denso on this truck...

 

[Rock_Rat]

You guys are awesome thanks. Last question though, what are the part numbers...? I have found 89615-12040 & 12090 that both say the fit the 5vz... And also what about the harness... Is it 82219-34010? And I have learned to always go oem denso on this truck...

Harness is correct. Sensor is 89615-12090. Both are the same pn. Be careful of ebay and even Amazon touting OEM. Lot of counterfeit stuff going on. Check out my up close pic of the OEM. Bought directly from the dealer. Don't use aftermarket sensors at all. You'll be tearing into it again. Glad to help.

 

[BlackRustBucket]

Just remembered [MENTION=120313]BlackRustBucket[/MENTION] put together some pretty good DIY pics back in April. Check out his thread.

http://www.toyota-4runner.org/3rd-gen-t4rs/194340-knock-sensors-harness-diy.html

Thanks buddy!

 

[z28forlife]

It could have been bad gas, Id try and clear the code for a while and see if it comes back. If it keeps returning then you know you need sensors or harness.

 

[Rock_Rat]

FSM Extraction

Here's an extract on the DTC. It's a very simple wiring circuit consisting of two sensors, wiring harness and ECM. Each sensor has a crystal inside it designed to generate 7.1kHz AC voltage return (electromagnetic (EM) wave frequency) to the ECM. It's called piezoelectricity. If the ECM doesn't see the frequency return then it enters fail-safe mode which is maximum timing retardation and turns on the CEL and generates the DTC for a failed sensor. Bad gas can cause your engine to knock but has nothing to do with the logic behind this DTC.

Also, included a photo of the shallow wiring harness channel.

 

[Illicitdream]

It could have been bad gas, Id try and clear the code for a while and see if it comes back. If it keeps returning then you know you need sensors or harness.

I was wondering the same thing... So I pulled the negative battery cable, cleaned the MAF (which was black and really dirty, gotta love living by dirt roads and having the deckplate mod done), Cleaned washable high flow air filter and cleaned the throttle body. I also seafoamed the truck again through the vacuum hose and put some in the gas tank as well. No code today, but it has only been a day and I live 2 miles from work... So we will find out later on if this has helped since my son goes to school 20 miles away and I'll be picking him up later on...

 

[Illicitdream]

Thanks buddy!

I read over your write up and was thoroughly impressed! Thanks for such a great write up! We will see if this is still an issue here after a week or so. I already have the parts ordered and being shipped (OEM of course). It would just be nice if I can return these items if it ends up not being the sensor or harness that is going out... But this might be a winter project that just needs to be done seeing that the runner now has 264k miles on it...

 

[Illicitdream]

Just an update... It's definitely the knock sensor. Check engine light came back on and threw the code for p0325 again.

 

[BlackRustBucket]

I read over your write up and was thoroughly impressed! Thanks for such a great write up! We will see if this is still an issue here after a week or so. I already have the parts ordered and being shipped (OEM of course). It would just be nice if I can return these items if it ends up not being the sensor or harness that is going out... But this might be a winter project that just needs to be done seeing that the runner now has 264k miles on it...

Thank you man, it's always appreciated to hear good feedback since it is very time consuming to put together. Just a few notes from my experience (not sure if I had them in the write up or not)...

1.) Good time to do spark plugs and valve cover gaskets
-If you decide to do the valve cover gaskets, make sure you also do the half-moon seals and I think there's another cam seal. I didn't do these and mine still leaks bad. IMO if it's not a problem already I would just snug down on the valve cover bolts and leave it be since just doing that works for a lot of people.

2.) If you have to wiggle the fuel rails out of the way and see any damaged o-rings on top of the injectors, or if one pops out of the manifold and seems excessively loose, I would replace the o-rings and/or by an injector seal kit to replace those.
-(Since mine was apart 3 or 4 times, an injector or 2 began to leak and spray fuel when it was running, until I replaced it, from being moved around so much.)

3.) You may want to look at the pages Rock_Rat sent and try to check the harness to ground and back to the ecm with a voltage meter set to ohms to look for a short.

I replaced both sensors and the harness section that connects to the sensors and still had the same code that you have for the same bank. To this day I haven't figured out the cause (probably the other section of wire harness that I didn't replace) but cleared the check engine light by using a wire tap and shorting the bad sensor wire to the good one lol. I don't know if doing that allowed the good signal to be sent to the bad sensors terminal on the ecm or what but that was my last resort (don't do that).

Last thing I'm going to say is when you get your old ones out, if you have access to an oscilloscope you can clip onto the pin coming out of the sensor and tap it on something and see if you see wave forms. If you think they're ok and it was the harness than you could resell them on ebay as used and get some decent money for each one. Good luck and if you have any questions please ask. It's really not a hard fix I am just too detail oriented and make it seem like a lot

 

[Illicitdream]

Thank you man, it's always appreciated to hear good feedback since it is very time consuming to put together. Just a few notes from my experience (not sure if I had them in the write up or not)...

1.) Good time to do spark plugs and valve cover gaskets
-If you decide to do the valve cover gaskets, make sure you also do the half-moon seals and I think there's another cam seal. I didn't do these and mine still leaks bad. IMO if it's not a problem already I would just snug down on the valve cover bolts and leave it be since just doing that works for a lot of people.

2.) If you have to wiggle the fuel rails out of the way and see any damaged o-rings on top of the injectors, or if one pops out of the manifold and seems excessively loose, I would replace the o-rings and/or by an injector seal kit to replace those.
-(Since mine was apart 3 or 4 times, an injector or 2 began to leak and spray fuel when it was running, until I replaced it, from being moved around so much.)

3.) You may want to look at the pages Rock_Rat sent and try to check the harness to ground and back to the ecm with a voltage meter set to ohms to look for a short.

I replaced both sensors and the harness section that connects to the sensors and still had the same code that you have for the same bank. To this day I haven't figured out the cause (probably the other section of wire harness that I didn't replace) but cleared the check engine light by using a wire tap and shorting the bad sensor wire to the good one lol. I don't know if doing that allowed the good signal to be sent to the bad sensors terminal on the ecm or what but that was my last resort (don't do that).

Last thing I'm going to say is when you get your old ones out, if you have access to an oscilloscope you can clip onto the pin coming out of the sensor and tap it on something and see if you see wave forms. If you think they're ok and it was the harness than you could resell them on ebay as used and get some decent money for each one. Good luck and if you have any questions please ask. It's really not a hard fix I am just too detail oriented and make it seem like a lot

Good info to know, thanks. I was thinking the same thing about the gaskets, just because I'm already in there so might as well get those done too. It seems that these sensors are usually an easy fix and the has been pin pointed to either a bad sensor or harness... I'm keeping my fingers crossed in hopes that when I install these parts the problem will be gone... hopefully. In the meantime I will just continue to clear the code with my scanner every day or two. Eventually once I get my Dakota up and running I can park the runner and work on this time consuming project... Thanks again for all the help and guidance.

 

[Illicitdream]

Thank you man, it's always appreciated to hear good feedback since it is very time consuming to put together. Just a few notes from my experience (not sure if I had them in the write up or not)...

1.) Good time to do spark plugs and valve cover gaskets
-If you decide to do the valve cover gaskets, make sure you also do the half-moon seals and I think there's another cam seal. I didn't do these and mine still leaks bad. IMO if it's not a problem already I would just snug down on the valve cover bolts and leave it be since just doing that works for a lot of people.

2.) If you have to wiggle the fuel rails out of the way and see any damaged o-rings on top of the injectors, or if one pops out of the manifold and seems excessively loose, I would replace the o-rings and/or by an injector seal kit to replace those.
-(Since mine was apart 3 or 4 times, an injector or 2 began to leak and spray fuel when it was running, until I replaced it, from being moved around so much.)

3.) You may want to look at the pages Rock_Rat sent and try to check the harness to ground and back to the ecm with a voltage meter set to ohms to look for a short.

I replaced both sensors and the harness section that connects to the sensors and still had the same code that you have for the same bank. To this day I haven't figured out the cause (probably the other section of wire harness that I didn't replace) but cleared the check engine light by using a wire tap and shorting the bad sensor wire to the good one lol. I don't know if doing that allowed the good signal to be sent to the bad sensors terminal on the ecm or what but that was my last resort (don't do that).

Last thing I'm going to say is when you get your old ones out, if you have access to an oscilloscope you can clip onto the pin coming out of the sensor and tap it on something and see if you see wave forms. If you think they're ok and it was the harness than you could resell them on ebay as used and get some decent money for each one. Good luck and if you have any questions please ask. It's really not a hard fix I am just too detail oriented and make it seem like a lot

Will driving around with the check engine light on throwing the P0325 code be bad? Will this do any damage to the engine?

 

[BlackRustBucket]

No, I just left mine on since it would come right back. It just retards the timing electronically to a safer position since it thinks the engine could really be knocking. You might get a little worse gas mileage

 

[Rock_Rat]

No, I just left mine on since it would come right back. It just retards the timing electronically to a safer position since it thinks the engine could really be knocking. You might get a little worse gas mileage

Here's my own opinion on that since I ran mine for almost a year with an intermittent code. Since your sensor is intermittent, I would continue to reset the CEL every time it came on. Let the ECM continue to run through it's cycle of advancing until it knocks and then retarding until it no longer knocks. This way you can continue to maintain a closed loop between the sensor and the ECM until it fails and defaults to a safe value. Personally, if I can get maximum performance out of my engine even for just a short time I'm going to do it.

With these resonant type sensors independently looking at each cylinder, the ECM will continue to reduce knock by utilizing it's spark advance map in the ECM even for just a few miles. When the CEL comes on and throws the code, the ECM will switch to it's regular defaulted map (max retardation) in an effort to do everything it can to protect your engine. When it get's to a point where every time you reset it the light comes back on then you know you have a hard fail and you must change it.

You have to love dynamic spark advance these days. The ECM even has the capability of storing a map based on the fuel you use. Because of this, my buddy feels the only difference you'll feel by using 92 octane fuel in these lower compression engines will be in your wallet.

Again, that's just my opinion.

 

[Rock_Rat]

Keep in mind that if you run any engine with retarded timing for any length of time you're looking at a much hotter engine and the possibility of burning out your valves and unnecessary wear to your cylinder, pistons, and rings.

When I ran mine for a year I was able to reset the code and it would go for days even weeks before it would come back on. Consequently, no potential damage to the engine. I immediately parked it when it would no longer clear for more than few miles.

 

[Illicitdream]

Keep in mind that if you run any engine with retarded timing for any length of time you're looking at a much hotter engine and the possibility of burning out your valves and unnecessary wear to your cylinder, pistons, and rings.

When I ran mine for a year I was able to reset the code and it would go for days even weeks before it would come back on. Consequently, no potential damage to the engine. I immediately parked it when it would no longer clear for more than few miles.

I agree^... The problem is though that I live out in the boonies and travel distance and time is at least 15+ miles of highway speed and 20-45 minutes of drive time one way. I have been resetting the code, but it's becoming more frequent when it comes back on. That means literally pulling off on the highway to reset the code and get back on the highway again to only have to resort doing this process again in 5-10 minutes... Thoughts? Should I just park it and do this project sooner than I had hoped?