2001 Ls430 P0325 Knock Sensor

[Zett123]

Ok, The check light came on my 2001 LS430 and the OBD2 is showing a... P0325 Knock Sensor 1 (Generic), Circuit (Bank1) error. Where exactly is this sensor located and how hard of a job is it to tackle? I don't have a shop but been working on cars for a long time. Also, how much is this part? Is it bad on the car to drive when it is like this?

[jaswood]

The knock sensor may only be the messenger...fuel injector not fully opening, etc.

[curiousB]

Ok, The check light came on my 2001 LS430 and the OBD2 is showing a... P0325 Knock Sensor 1 (Generic), Circuit (Bank1) error. Where exactly is this sensor located and how hard of a job is it to tackle? I don't have a shop but been working on cars for a long time. Also, how much is this part? Is it bad on the car to drive when it is like this?

There are two of them. Part is 89615 on diagram. If you are inclined you could swap them and see if the problem moves with the sensor or stays with the same bank. If it stays it might be something as suggested by jaswood.

[steve2006]

Also are you using premium gas?

[Zett123]

Yes, I always use Premium gas.. How hard of job is this and oes the intake manifold have to come off?

[Zett123]

Update.. I doubt it is an injector.. If I start the car and then the check light comes on, it runs rough. However, when the check light is on and I restart the car, it runs smooth. Maybe not 100% but no too noticeable.

Anyone replace the knock sensors on a 2001-2003 LS430?

[jaswood]

Back in the days of carburetion running rough would always mean carburetor or ignition problems. Modern ignition system problems rarely result in knock/ping. You most likely have an intermitently STUCK fuel injector, mayb even a failing fuel pump(filter?). But first be sure and clean the MAF/IAT sensors, just on the chance.

[maniek_LS]

Update.. I doubt it is an injector.. If I start the car and then the check light comes on, it runs rough. However, when the check light is on and I restart the car, it runs smooth. Maybe not 100% but no too noticeable.

Anyone replace the knock sensors on a 2001-2003 LS430?

Hi,

I own 2001 LS430 and have the same issue - exact the same error (my colleague also has in LS430 error P0325). I replaced knock sensor to used one and error comes again, my colleague replaced both knock sensors (also used) and P0325 appears again. Job is not so easy - you have to remove intake (see attached doc m_10_0010.pdf).

Also it is not easy to switch RH with LH sensors - you have to remove intake two times (some gaskets are non-reusable - costs goes high.

During weekend I'm going to connect oscilloscope and check sensor readings and cabling - maybe something is on wires? In service manual (m_di_0079.pdf) there is method to swap pins in plug and if error will remain on the same bank - problem will be in cable from connector to knock sensor or in a sensor.

I can not believe that only knock sensor can throw this code - few people has problem only with the same P0325 (bank 1) no one is talking that bank 2 sensor was wrong. What do you thing ?

Do somebody know - maybe knock sensors aren't re-usable ?

I use petrol 95 or 98, MAF cleaned, air filter new OEM. In my opinion if something will be wrong with air error will also appear on bank2 not only bank1.

Waiting for your answers.

Thank you,

Regards

m_10_0010.pdf

m_di_0079.pdf

[jaswood]

Update.. I doubt it is an injector.. If I start the car and then the check light comes on, it runs rough. However, when the check light is on and I restart the car, it runs smooth. Maybe not 100% but no too noticeable.

Anyone replace the knock sensors on a 2001-2003 LS430?

Hi,

I own 2001 LS430 and have the same issue - exact the same error (my colleague also has in LS430 error P0325). I replaced knock sensor to used one and error comes again, my colleague replaced both knock sensors (also used) and P0325 appears again. Job is not so easy - you have to remove intake (see attached doc m_10_0010.pdf).

Also it is not easy to switch RH with LH sensors - you have to remove intake two times (some gaskets are non-reusable - costs goes high.

During weekend I'm going to connect oscilloscope and check sensor readings and cabling - maybe something is on wires? In service manual (m_di_0079.pdf) there is method to swap pins in plug and if error will remain on the same bank - problem will be in cable from connector to knock sensor or in a sensor.

I can not believe that only knock sensor can throw this code - few people has problem only with the same P0325 (bank 1) no one is talking that bank 2 sensor was wrong. What do you thing ?

Do somebody know - maybe knock sensors aren't re-usable ?

I use petrol 95 or 98, MAF cleaned, air filter new OEM. In my opinion if something will be wrong with air error will also appear on bank2 not only bank1.

Waiting for your answers.

Our '95 LS was recently giving a code indicating bank 1 was running too lean. The LS400 factory shop/repair manual suggested the MAF/IAT might be at fault. That was hard for me to believe but cleaning the MAF was a much easier job than anything else I might tackle.

Amazingly enough that did clear the problem.

And....

For more than a year we have been getting intermittent EGR faults. Cleaned the EGR, replaced misc parts, no help. I could reset the fault but it would come back on within 2-3 weeks.

Since I cleaned the MAF no more EGR faults...

Only the shadow knows....

[Zett123]

First off, thanks for the replies to this P0325 knock sensor problem and possible causes. My question is, why would anyone go through all the trouble of replacing a knock sensor(s)on an LS430 with 'used' sensors. If one of the used sensors is defective, it opens up a can of worms for trying to diagnose the problem. They are $133.00 new from Pembroke Pines FL Lexus. If it is a MAF or injector problem, wouldn't both sensors be showing a problem other than just one. I should of pointed out, that I have 139K miles on the car and I just had the timing belt replaced about a month ago. (Just a tad pass the 90K recommendation). My guy (great mechanic) also replaced the plugs, air filter, hydraulic adjuster, tensioner and pulleys at the same time. ($980.00 parts and labor)

I can't wait until "maniek_LS" works on his P0325 this weekend to see what he comes up with. Until then, I will clean the MAF sensor per chance it might be a problem. This is the 21st century, seems like they should have a better way of diagnosing these codes without a lot of guess work.

On a side note, in the last 40 years, I have owned about 40 Auto's, new and used. This LS430 is the best car I have ever owned and my next car will be no doubt, a LS460. Other than the POC ML stereo system, this car is the bomb!!

Thanks in advance!!

JZ

[maniek_LS]

I can't wait until "maniek_LS" works on his P0325 this weekend to see what he comes up with. Until then, I will clean the MAF sensor per chance it might be a problem.

Cleaning MAF took me 15 minutes. I did this when I changed air filter to new one - no changes with P0325. Used knock sensor - $50, new - $300. In repair manual there is method to check if sensor hasn't shorts etc. I'm bad on myself that I'm not checked it before send car to mechanic - I had no time to replace knock sensor by myself. During weekend I'll find what is wrong.

On the internet I found solution to connect ECU wire of wrong sensor to sensor which is working properly - it make sens because both sensors are close each other, and no power is applied to them. ECU just receive signal generated by KS.

I'll post update here.

[landar]

This LS329 is the best car I have ever owned and my next car will be no doubt, a LS460. Other than the POC ML stereo system, this car is the bomb!!

Interesting. Where can I get one of these LS329's? ;)

Do you happen to know what brand of T-belt was used in your recent change? If the belt were to be off by a tooth or sloppy.....I wonder if maniek recently had his T-belt changed?

[maniek_LS]

Timing belt could throw P0325 code ? I understand that ODB2 is created to stop with probes in car diagnostic and repair and to show what exactly wrong is in the car ?

BTW. I don't know history of my car - I bought it on September 2011 (with Check Engine ON), but I taken into consideration that some repairs will be required.

[curiousB]

On the internet I found solution to connect ECU wire of wrong sensor to sensor which is working properly - it make sens because both sensors are close each other, and no power is applied to them. ECU just receive signal generated by KS.

I'll post update here.

I've seen similar recommendations for spoofing secondary O2 sensors by driving the ECU from one good sensor and just disconnecting the faulty one (the signal line only, since there is error trap on current draw of heater element as well). The issue you have with the knock sensor is it has a purpose that you will be defeating. The sensor is to alert the ecu of improper firing in a cylinder and the ECU will adjust timing and perhaps fuel to trim out the problem and avoid damage. If you connect the wrong sensor to the other bank ECU input the ECU will see knock pulses that it thinks relate to the bank it is controlling and will take incorrect action to trim. Similarly it won't hear the ones it should hear. If you are trying to just keep the car alive for a few weeks or months until it goes to the scrap heap this might be an acceptable compromise. If you intend to keep it a while or possibly sell it to someone later you should fix this. Lexus didn't put in these sensors, extra electronics and ECU software just for the fun of it.

[curiousB]

I understand that ODB2 is created to stop with probes in car diagnostic and repair and to show what exactly wrong is in the car ?

Modern EFI engines are complicated Closed Loop systems. Closed loop means that inputs (throttle position, pedal position, engine temp, air temp, O2 sensors, ...) are fed into the ECU to make decisions on how to control the engine (timing, fuel/air). Since they are closed loop everything interacts with each other. This makes diagnosis tricky. If you want an example of closed loop in action, crack open a sizable air leak in the air duct after the MAF on the intake. You'll hear the engine labor and try to adjust to this inrush of unmetered air. LT fuel trim will go up by 10-20% depending on size of leak. That is the feedback loop trying to correct the (lean condition seen by the O2 sensors) condition.

So while the cars have a lot more self diagnostic capability some diagnostic issues are subtle and not as simple as "P0xyz= change this part"...

[maniek_LS]

On the internet I found solution to connect ECU wire of wrong sensor to sensor which is working properly - it make sens ......

I've seen similar recommendations for spoofing secondary O2 sensors by driving the ECU from one good sensor and just disconnecting the faulty one (the signal line only, since there is error trap on current draw of heater element as well). The issue you have with the knock sensor is it has a purpose that you will be defeating. The sensor is to alert the ecu of improper firing in a cylinder and the ECU will adjust timing and perhaps fuel to trim out the problem and avoid damage. If you connect the wrong sensor to the other bank ECU input the ECU will see knock pulses that it thinks relate to the bank it is controlling and will take incorrect action to trim. Similarly it won't hear the ones it should hear. If you are trying to just keep the car alive for a few weeks or months until it goes to the scrap heap this might be an acceptable compromise. If you intend to keep it a while or possibly sell it to someone later you should fix this. Lexus didn't put in these sensors, extra electronics and ECU software just for the fun of it.

My every car is/was in very good condition. I don't like to use workarounds instead of problem diagnose and repair.

I say that find this solution - but I'm not going to do this in my car. Repair Manual recommend to exchange KS cables which comes from E1 to ECU - I'll try find KS issue as described in manual. What do you think - can leaked injector throw this problem ?

My ideas for weekend are:

1. measure wiring(s)

2. measure KS as possible

3. exchange KS outputs to ECU (and go back with them after error will appear)

4. change all injectors from RH to LH

5. remove KS and replace with new one (next weekend if steps 1-4 say that KS bank 1 is faulty).

Thank you for answers,

[maniek_LS]

My repair plans were moved to Monday... In the meantime I have two questions - both surprising me:

1. bank 1 - my car is LHD - if I'm at front of Lexus and then steering wheel is on my right - bank 1 is on my right or left side ? Till today I thought that on my left side (driver side) is it correct ? (from DI-79 - DTC P0325/52 is for the left bank knock sensor circuit)

2. Engine ECU in LS430 models is under hood (in my also) - then why in Repair Manual "DI-79" part "when not using hand-held tester" author wrote:

PREPARATION:

a Remove the instrument panel under cover.

b Disconnect the E4 connector of engine ECU.

Thanks,

Mariusz

[Zett123]

I am taking my LS430 to my guy (mechanic) next Tuesday or Wednesday. He is going to run some diagnostics on the sensor(s) and check to see if the output is what it should be. For me, it would be nice to have some test points (TP's) with voltage outputs and ranges and I would check them with an oscilloscope.

Bank one (1) is drivers side.

jz

[maniek_LS]

..For me, it would be nice to have some test points (TP's) with voltage outputs and ranges and I would check them with an oscilloscope.

Bank one (1) is drivers side.

jz

I posted document (m_di_0079.pdf) where you can find waveforms of KS. Thank you for bank1 - driver side clarification.

[curiousB]

If you think it may be a stuck open fuel injector (too much fuel to one cylinder) causing knock then it might be easier to try one of those fuel system cleaners first. A lot easier than pulling 8 injectors. Also cheaper as you'll need all new o-Rings for each injector you pull. I've read the injector plastic body and cable connector shell get brittle with age so proceed with caution.

[maniek_LS]

If you think it may be a stuck open fuel injector (too much fuel to one cylinder) causing knock then it might be easier to try one of those fuel system cleaners first. A lot easier than pulling 8 injectors. Also cheaper as you'll need all new o-Rings for each injector you pull. I've read the injector plastic body and cable connector shell get brittle with age so proceed with caution.

curiousB thank you for suggestion about injectors, but in my case they were out and checked by mechanic when he changed KS three weeks ago. Of course all o-rings were replaced to OEM. I also used STP (fuel system cleaner) few times - no positive changes. Sparks OEM - replaced with o-rings too.

[maniek_LS]

Good news !

Last Tuesday I changed knock sensor in bank1 (P0325) in meantime cleaned throttle body and my LS430 is now running with no ML light ! :D

Until I did repair (about two weeks) - I used my car with workaround (I cut black wire close to engine ECU connector E7 pin 1 and connected input of engine ECU KS bank1 to proper working ECU KS bank2 connector E7 pin 2. ML also not appear, engine worked with no problems.

Attached photo of workaround on engine ECU.

By maniek_ls400 at 2011-12-18

By maniek_ls400 at 2011-12-18

[Zett123]

UPDATE on error code P0325: I purchased 2 new knock sensors from Lexus of Pembroke Pines, Florida. Price $297.00 including shipping to Maryland. (Their shipping price is based on a percentage of the item) Still best price for OEM Toyota parts I found anywhere, Ebay included. I had my independent mechanic install them for a price of $270.00 labor. After he put everything back together, he got a 1/2 dozen error codes. The problem? The pins, connectors and wiring were brittle so he spent hours repairing them. He has the Lexus schematics and voltage information to get accurate readings on whatever needed to be repaired.

When I took the car home from his shop, I couldn't believe how much power this car has. It has not run this well since I brought it. The total bill was $413.00 including the extra hours of repair and gasket set. I thought was a bargain for all the extra work he had to do and I am glad I didn't try to tackle this job myself. So if you are going to try to replace the knock sensors yourself, please be careful of the wiring and pins on the ignition circuit.

JZ

[curiousB]

good stuff. I think the repair bill for that was reasonable given the effort required to get at these sensors. Happy motoring...

[evil2]

Just replaced my knock sensor for 96 ls400 for error code p0330. The sensor was the passenger side one and i found a new one on ebay for $70. I looked down the driver side of the intake manifold and the sensors are right there. I got the sensor out without removing any engine parts and it took about ten minutes to get out and same to replace. i did have to use a pair of laparoscopic graspers and a flexible ratcheting tbar from harbor freight. You also need a 1 1/16 socket.