Knock Sensor - CEL P0325 - SC430
09-09-16, 06:20 AM
#1
Instructor
Thread Starter
Knock Sensor - CEL P0325 - SC430
Friends,
My high-mileage 2002 Lexus SC430 threw a "check engine light" on a particularly hot and muggy day, and the engine lost most of it's power.
When this happened, the V8 in the SC430 felt more like a V4... flooring the accelerator pedal would introduce a 5 second lag before the car started to speed up.
After shutting off and restarting the engine, the engine acceleration lag disappeared (but the CEL stayed on).
I checked the code with an ODBII tool, and it showed "P0325" (Knock Sensor Circuit Malfunction).
I reset the CEL, and drove for 15 miles with no issues... thus far.
I'm wondering if any has experienced this Knock Sensor code ("P0325") on the SC430, or the very significant acceleration lag.
(I have been using 93 octane gasoline exclusively for the past five years on this SC430).
Any thoughts would be welcome.
Thank you
My high-mileage 2002 Lexus SC430 threw a "check engine light" on a particularly hot and muggy day, and the engine lost most of it's power.
When this happened, the V8 in the SC430 felt more like a V4... flooring the accelerator pedal would introduce a 5 second lag before the car started to speed up.
After shutting off and restarting the engine, the engine acceleration lag disappeared (but the CEL stayed on).
I checked the code with an ODBII tool, and it showed "P0325" (Knock Sensor Circuit Malfunction).
I reset the CEL, and drove for 15 miles with no issues... thus far.
I'm wondering if any has experienced this Knock Sensor code ("P0325") on the SC430, or the very significant acceleration lag.
(I have been using 93 octane gasoline exclusively for the past five years on this SC430).
Any thoughts would be welcome.
Thank you
09-15-16, 08:11 AM
#3
Instructor
Thread Starter
This happened again today 
It's a strange feeling loosing most of the engine's power while driving. Luckily, a quick engine restart remedied the immediate loss-of-power issue.
Interestingly, I also got a very strong smell in the cabin of the car when the CEL came on and I lost most of the power... like rotten eggs or something.
Based on what I've seen in other threads, to remedy it's 3.5 hours of labor plus the cost of the sensors.
Will have to consider my options... has anyone else battled the knock sensor issue lately?
It's a strange feeling loosing most of the engine's power while driving. Luckily, a quick engine restart remedied the immediate loss-of-power issue.
Interestingly, I also got a very strong smell in the cabin of the car when the CEL came on and I lost most of the power... like rotten eggs or something.
Based on what I've seen in other threads, to remedy it's 3.5 hours of labor plus the cost of the sensors.
Will have to consider my options... has anyone else battled the knock sensor issue lately?
09-15-16, 08:26 AM
#4
This happened again today
It's a strange feeling loosing most of the engine's power while driving. Luckily, a quick engine restart remedied the immediate loss-of-power issue.
Interestingly, I also got a very strong smell in the cabin of the car when the CEL came on and I lost most of the power... like rotten eggs or something.
Based on what I've seen in other threads, to remedy it's 3.5 hours of labor plus the cost of the sensors.
Will have to consider my options... has anyone else battled the knock sensor issue lately?
It's a strange feeling loosing most of the engine's power while driving. Luckily, a quick engine restart remedied the immediate loss-of-power issue.
Interestingly, I also got a very strong smell in the cabin of the car when the CEL came on and I lost most of the power... like rotten eggs or something.
Based on what I've seen in other threads, to remedy it's 3.5 hours of labor plus the cost of the sensors.
Will have to consider my options... has anyone else battled the knock sensor issue lately?
the sulfur smell comes from the immediate rich fuel mixture. This is the computers response to the knock sensor fault. Here is an explanation of the chemistry of it.
Here this will explain why you have the smell. As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.this is something I wrote in an old discussion on catalytic converter thread.
09-15-16, 08:49 AM
#5
Instructor
Thread Starter
Great insight, Coleroad!
the sulfur smell comes from the immediate rich fuel mixture. This is the computers response to the knock sensor fault. Here is an explanation of the chemistry of it. Here this will explain why you have the smell. As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
this is something I wrote in an old discussion on catalytic converter thread.
Here this will explain why you have the smell. As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.this is something I wrote in an old discussion on catalytic converter thread.
09-15-16, 11:24 AM
#6
Pole Position
Since the plugs are much easier to get to than the sensor, it maybe worth your time.
Just a guess though.
I did read somewhere that when you change your knock sensor, you should also change the harness.
09-16-16, 06:48 AM
#7
Instructor
Thread Starter
DashingDar, that's a good point. Will have to take a look at that.
The spark plugs were replaced 5 years ago, about 35,000 miles ago.
Thank you for the input.
The spark plugs were replaced 5 years ago, about 35,000 miles ago.
Thank you for the input.
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09-21-16, 06:53 AM
#8
Instructor
Thread Starter
I've been living with this issue for several weeks now. It's quite annoying.
Some folks have suggested adding a "Fuel Injection Cleaner" to attempt to address the issue... I'm wondering if anyone has used a "Fuel Injection Cleaner" on an SC430?
Some folks have suggested adding a "Fuel Injection Cleaner" to attempt to address the issue... I'm wondering if anyone has used a "Fuel Injection Cleaner" on an SC430?
09-21-16, 07:52 AM
#9
Jasone, the p0325 code is because the sensor reading is outside parameters. It is not because of pre-detonation happing. You have a problem with that circuit, either the harness, or sensor(s). When the fault happens the computer goes into limp mode to protect the engine.
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shalomhome (05-27-24)
08-15-19, 03:00 AM
#10
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2002 sc430
I'm going through a very similar thing. I had it on ECT power and was driving at pretty high performance and suddenly it through a check engine light at me and lost most of its horsepower.
a quick code read shows a fault in the knock sensor. I've gotten several quotes and everything is between 700 and $1,000.
I've thrown so much money into this car over the last two years, I swear to God if it wasn't my favorite car I've ever owned....
a quick code read shows a fault in the knock sensor. I've gotten several quotes and everything is between 700 and $1,000.
I've thrown so much money into this car over the last two years, I swear to God if it wasn't my favorite car I've ever owned....
This happened again today
It's a strange feeling loosing most of the engine's power while driving. Luckily, a quick engine restart remedied the immediate loss-of-power issue.
Interestingly, I also got a very strong smell in the cabin of the car when the CEL came on and I lost most of the power... like rotten eggs or something.
Based on what I've seen in other threads, to remedy it's 3.5 hours of labor plus the cost of the sensors.
Will have to consider my options... has anyone else battled the knock sensor issue lately?
It's a strange feeling loosing most of the engine's power while driving. Luckily, a quick engine restart remedied the immediate loss-of-power issue.
Interestingly, I also got a very strong smell in the cabin of the car when the CEL came on and I lost most of the power... like rotten eggs or something.
Based on what I've seen in other threads, to remedy it's 3.5 hours of labor plus the cost of the sensors.
Will have to consider my options... has anyone else battled the knock sensor issue lately?
08-15-19, 04:22 PM
#11
Pole Position
If it is your knock sensor, my heart goes out to you. The sensors are located under your manifold near your starter.
I think SIXONEMALE did a write up about it.
Here is a video from our sister car, the LS430. It isn't a how to, but it will give you an idea of the scope of the problem
I think SIXONEMALE did a write up about it.
Here is a video from our sister car, the LS430. It isn't a how to, but it will give you an idea of the scope of the problem
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