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Posted

Hello everyone,

I just spent the last week going crazy trying to fix a "knock sensor" code P0330 on my RX300. So to save the next guy a little aggravation here is what I found out.

The dealer was trying to charge an "arm and a leg" to fix this problem (parts & labor). :cries:

Parts you are going to need:

1. Knock sensor

2. Knock sensor wiring harness

3. Intake gaskets

4. By-pass hose

5. Antifreeze

Lexus quoted me a price of $198.00 per sensor. (The car has 2 sensors, if you’re going to go through the trouble of changing them, change them both!)

After several hours of bothering the hell out of the parts guy at Lexus he told me that the part number for the knock sensor I needed was 896145-12040. I was able to order these from partsquick.com for $97.94 each. These are Genuine Toyota parts and were at my door in two days.

I ordered the intake gasket kit from rockauto.com for $56.79 this was a FEL-PRO part number MS92766 it came with all 3 gaskets.

I did order the wiring harness and by-pass hose from Lexus because I didn't have the energy to go through the whole mess again. They charged me $42.00 for the harness and $18.00 for the hose. When I got them I peeled back the Lexus sticker to reveal a Genuine Toyota sticker underneath! The Toyota part number for the wiring harness is 82219-07010 and the Toyota part number for the by-pass hose is 16261-20010. I’m sure with a little searching you can find this cheaper as well. Definitely order the by-pass hose because the hose is almost impossible to remove and I had to cut it off.

It took me 9 hours to change the knock sensors. It is not an easy job. You have to remove the whole top half of the engine.

I guess my best advice for anyone that’s going to tackle this project is to get a small 1/4" ratchet with a swivel head. I used this to get to the intake bracket mount bolts (2), as well as the ground bolt and fuel line bracket bolt that are located behind the intake, there’s not much room back there but this saved me tons of time.

Oh! and you might as well change the spark plugs cause they are breeze to change with half the engine missing.

Here are some pics of the whole ordeal. Hope this helps. Good Luck

Jason

knck sensor part number

wiring harness

by-pass hose

wiring harness part number

parts i had to remove!

engine with all parts out of the way

sensors and wiring harness with by-pass hose removed

Posted

Hey thank you, great post, I saved it for reference....

Posted

So, a little over $300 plus 9 hours of labor.

What did Lexus want to replace them?

  • 2 weeks later...
Posted

Hi everyone,

I want 1st to thank this article. It give me some idea of how to replace both knock sensors. It did take me about 8 hr to perform this task. It was also helpful to replace the spark plugs at the sametime (if has high mileages).

This is my story on 00 RX 300, FWD with 69000 miles: I have code P0330 and P0171 codes on. I was not able to get into over drive on my tranny. Took my car into 3 shops and all indicasted needed tranny overhaul, eventhough there were no tranny codes from the CEL. After did few researches, I came acorss w/ an artical that fited my problem and decided to tackled these knock sensors first. I did the work last Monday and the tranny is working fine SO FAR. The P0330 code was gone. Last nite, I removed and cleaned the mass flow sensor and now do not have this P0171 code anymore (knock on the woods so far). Hopfully, someone will do more research, and eliminate the codes 1 by 1, before replace/repair the tranny. It sure saved me approx. $4500.00.

One thing that I would add is that the by-pass hose: it does not have to be removed to replace the sensors, just have to move it side by side to get to the sensors. I was able to remove it w/o damaging it.

The common socket sizes are 10mm, 12mm and 14 mm and a 1 1/1" wrench (to remove the sensors - they were not very tight so they were very easily removed w/o breaking any knockles). One more item to remember, you only have to remove a single bolt, on both the air intake chamber bracket and the other bracket - only at the engine block, then the air intake chamber/throttle body can be lifted up and out at an angle. THis will save you alot of headaches as other two bots are in very tight spots and almost impossible to get the tool on them. If possible, purchase a service manual or get a copy of the air chamber/intake manifold instruction. It was a big help.

Good luck if anyone is trying to work on it themselves.

Hello everyone,

I just spent the last week going crazy trying to fix a "knock sensor" code P0330 on my RX300. So to save the next guy a little aggravation here is what I found out.

The dealer was trying to charge an "arm and a leg" to fix this problem (parts & labor). :cries:

Parts you are going to need:

1. Knock sensor

2. Knock sensor wiring harness

3. Intake gaskets

4. By-pass hose

5. Antifreeze

Lexus quoted me a price of $198.00 per sensor. (The car has 2 sensors, if you’re going to go through the trouble of changing them, change them both!)

After several hours of bothering the hell out of the parts guy at Lexus he told me that the part number for the knock sensor I needed was 896145-12040. I was able to order these from partsquick.com for $97.94 each. These are Genuine Toyota parts and were at my door in two days.

I ordered the intake gasket kit from rockauto.com for $56.79 this was a FEL-PRO part number MS92766 it came with all 3 gaskets.

I did order the wiring harness and by-pass hose from Lexus because I didn't have the energy to go through the whole mess again. They charged me $42.00 for the harness and $18.00 for the hose. When I got them I peeled back the Lexus sticker to reveal a Genuine Toyota sticker underneath! The Toyota part number for the wiring harness is 82219-07010 and the Toyota part number for the by-pass hose is 16261-20010. I’m sure with a little searching you can find this cheaper as well. Definitely order the by-pass hose because the hose is almost impossible to remove and I had to cut it off.

It took me 9 hours to change the knock sensors. It is not an easy job. You have to remove the whole top half of the engine.

I guess my best advice for anyone that’s going to tackle this project is to get a small 1/4" ratchet with a swivel head. I used this to get to the intake bracket mount bolts (2), as well as the ground bolt and fuel line bracket bolt that are located behind the intake, there’s not much room back there but this saved me tons of time.

Oh! and you might as well change the spark plugs cause they are breeze to change with half the engine missing.

Here are some pics of the whole ordeal. Hope this helps. Good Luck

Jason

knck sensor part number

wiring harness

by-pass hose

wiring harness part number

parts i had to remove!

engine with all parts out of the way

sensors and wiring harness with by-pass hose removed

Posted

Just a copule correction on my last post. My RX300 was a AWD and not a FWD. The wrench for the sensor is 1 1/16" (it just got cut off accidently). As far as the by-pass hose goes, I would strongly recommendated to replace it it it is a high mileage vehicle, at the time of the service.

Again, good luck to everyone.

Hi everyone,

I want 1st to thank this article. It give me some idea of how to replace both knock sensors. It did take me about 8 hr to perform this task. It was also helpful to replace the spark plugs at the sametime (if has high mileages).

This is my story on 00 RX 300, FWD with 69000 miles: I have code P0330 and P0171 codes on. I was not able to get into over drive on my tranny. Took my car into 3 shops and all indicasted needed tranny overhaul, eventhough there were no tranny codes from the CEL. After did few researches, I came acorss w/ an artical that fited my problem and decided to tackled these knock sensors first. I did the work last Monday and the tranny is working fine SO FAR. The P0330 code was gone. Last nite, I removed and cleaned the mass flow sensor and now do not have this P0171 code anymore (knock on the woods so far). Hopfully, someone will do more research, and eliminate the codes 1 by 1, before replace/repair the tranny. It sure saved me approx. $4500.00.

One thing that I would add is that the by-pass hose: it does not have to be removed to replace the sensors, just have to move it side by side to get to the sensors. I was able to remove it w/o damaging it.

The common socket sizes are 10mm, 12mm and 14 mm and a 1 1/1" wrench (to remove the sensors - they were not very tight so they were very easily removed w/o breaking any knockles). One more item to remember, you only have to remove a single bolt, on both the air intake chamber bracket and the other bracket - only at the engine block, then the air intake chamber/throttle body can be lifted up and out at an angle. THis will save you alot of headaches as other two bots are in very tight spots and almost impossible to get the tool on them. If possible, purchase a service manual or get a copy of the air chamber/intake manifold instruction. It was a big help.

Good luck if anyone is trying to work on it themselves.

Hello everyone,

I just spent the last week going crazy trying to fix a "knock sensor" code P0330 on my RX300. So to save the next guy a little aggravation here is what I found out.

The dealer was trying to charge an "arm and a leg" to fix this problem (parts & labor).:cries:

Parts you are going to need:

1. Knock sensor

2. Knock sensor wiring harness

3. Intake gaskets

4. By-pass hose

5. Antifreeze

Lexus quoted me a price of $198.00 per sensor. (The car has 2 sensors, if you’re going to go through the trouble of changing them, change them both!)

After several hours of bothering the hell out of the parts guy at Lexus he told me that the part number for the knock sensor I needed was 896145-12040. I was able to order these from partsquick.com for $97.94 each. These are Genuine Toyota parts and were at my door in two days.

I ordered the intake gasket kit from rockauto.com for $56.79 this was a FEL-PRO part number MS92766 it came with all 3 gaskets.

I did order the wiring harness and by-pass hose from Lexus because I didn't have the energy to go through the whole mess again. They charged me $42.00 for the harness and $18.00 for the hose. When I got them I peeled back the Lexus sticker to reveal a Genuine Toyota sticker underneath! The Toyota part number for the wiring harness is 82219-07010 and the Toyota part number for the by-pass hose is 16261-20010. I’m sure with a little searching you can find this cheaper as well. Definitely order the by-pass hose because the hose is almost impossible to remove and I had to cut it off.

It took me 9 hours to change the knock sensors. It is not an easy job. You have to remove the whole top half of the engine.

I guess my best advice for anyone that’s going to tackle this project is to get a small 1/4" ratchet with a swivel head. I used this to get to the intake bracket mount bolts (2), as well as the ground bolt and fuel line bracket bolt that are located behind the intake, there’s not much room back there but this saved me tons of time.

Oh! and you might as well change the spark plugs cause they are breeze to change with half the engine missing.

Here are some pics of the whole ordeal. Hope this helps. Good Luck

Jason

knck sensor part number

wiring harness

by-pass hose

wiring harness part number

parts i had to remove!

engine with all parts out of the way

sensors and wiring harness with by-pass hose removed

Posted

Great job, thanks for the very informative info....

  • 5 months later...
Posted
Hi,

Can you tell me what the story is with the "by pass hose"? What is it for?

Thanks

It is a water hose that is impossible to change without removing the intake manifold, while you are in there it would be cheap preventative maintenance to replace it.

  • 2 weeks later...
Posted

Hi all,

I am having the same issue with my RX300 but the only difference is that mine is a 2000. Would these part numbers be the same or are they different between 99 and 00. Please advise so that I can order these parts.

Thanks,

Just a copule correction on my last post. My RX300 was a AWD and not a FWD. The wrench for the sensor is 1 1/16" (it just got cut off accidently). As far as the by-pass hose goes, I would strongly recommendated to replace it it it is a high mileage vehicle, at the time of the service.

Again, good luck to everyone.

Hi everyone,

I want 1st to thank this article. It give me some idea of how to replace both knock sensors. It did take me about 8 hr to perform this task. It was also helpful to replace the spark plugs at the sametime (if has high mileages).

This is my story on 00 RX 300, FWD with 69000 miles: I have code P0330 and P0171 codes on. I was not able to get into over drive on my tranny. Took my car into 3 shops and all indicasted needed tranny overhaul, eventhough there were no tranny codes from the CEL. After did few researches, I came acorss w/ an artical that fited my problem and decided to tackled these knock sensors first. I did the work last Monday and the tranny is working fine SO FAR. The P0330 code was gone. Last nite, I removed and cleaned the mass flow sensor and now do not have this P0171 code anymore (knock on the woods so far). Hopfully, someone will do more research, and eliminate the codes 1 by 1, before replace/repair the tranny. It sure saved me approx. $4500.00.

One thing that I would add is that the by-pass hose: it does not have to be removed to replace the sensors, just have to move it side by side to get to the sensors. I was able to remove it w/o damaging it.

The common socket sizes are 10mm, 12mm and 14 mm and a 1 1/1" wrench (to remove the sensors - they were not very tight so they were very easily removed w/o breaking any knockles). One more item to remember, you only have to remove a single bolt, on both the air intake chamber bracket and the other bracket - only at the engine block, then the air intake chamber/throttle body can be lifted up and out at an angle. THis will save you alot of headaches as other two bots are in very tight spots and almost impossible to get the tool on them. If possible, purchase a service manual or get a copy of the air chamber/intake manifold instruction. It was a big help.

Good luck if anyone is trying to work on it themselves.

Hello everyone,

I just spent the last week going crazy trying to fix a "knock sensor" code P0330 on my RX300. So to save the next guy a little aggravation here is what I found out.

The dealer was trying to charge an "arm and a leg" to fix this problem (parts & labor).:cries:

Parts you are going to need:

1. Knock sensor

2. Knock sensor wiring harness

3. Intake gaskets

4. By-pass hose

5. Antifreeze

Lexus quoted me a price of $198.00 per sensor. (The car has 2 sensors, if you’re going to go through the trouble of changing them, change them both!)

After several hours of bothering the hell out of the parts guy at Lexus he told me that the part number for the knock sensor I needed was 896145-12040. I was able to order these from partsquick.com for $97.94 each. These are Genuine Toyota parts and were at my door in two days.

I ordered the intake gasket kit from rockauto.com for $56.79 this was a FEL-PRO part number MS92766 it came with all 3 gaskets.

I did order the wiring harness and by-pass hose from Lexus because I didn't have the energy to go through the whole mess again. They charged me $42.00 for the harness and $18.00 for the hose. When I got them I peeled back the Lexus sticker to reveal a Genuine Toyota sticker underneath! The Toyota part number for the wiring harness is 82219-07010 and the Toyota part number for the by-pass hose is 16261-20010. I’m sure with a little searching you can find this cheaper as well. Definitely order the by-pass hose because the hose is almost impossible to remove and I had to cut it off.

It took me 9 hours to change the knock sensors. It is not an easy job. You have to remove the whole top half of the engine.

I guess my best advice for anyone that’s going to tackle this project is to get a small 1/4" ratchet with a swivel head. I used this to get to the intake bracket mount bolts (2), as well as the ground bolt and fuel line bracket bolt that are located behind the intake, there’s not much room back there but this saved me tons of time.

Oh! and you might as well change the spark plugs cause they are breeze to change with half the engine missing.

Here are some pics of the whole ordeal. Hope this helps. Good Luck

Jason

knck sensor part number

wiring harness

by-pass hose

wiring harness part number

parts i had to remove!

engine with all parts out of the way

sensors and wiring harness with by-pass hose removed

  • 3 months later...
Posted

Hey, can anyone tell me where i can find the repair manual for my lexus rx 300? I've been searching around and I can't seem to find it anymore.

thanks

  • 2 weeks later...
  • 3 weeks later...
Posted

Hi Everyone,

I have a 2000 rx300 and also had the P0330 code which came with bad performance, lots of knocking and not being able to go into overdrive after about 20 minutes of driving.

After reading the above "incredible" posts, I successfully replaced both Knock sensors and harness as well as the water transfer hose and spark plugs (because I was there).

I just wanted to contribute areas I thought were the most difficult and got stuck and had to go looking for a better tool etc.

The upper intake manifold was the biggest problem. There are three bolts at the back, so close to the firewall you can't see and will have a problem reaching with your finger let along a tool.

The first is a 14mm bolt on "your" far left side. It screws the Upper intake manifold to a bracket to stabilize it. The bracket has sides that make it difficult to reach the bolt. You can feel it with your finger however (if you work hard to get your hand back there). I couldn't use my standard socket wrench as it was to fat to clear that area. I had to go out and get a "gearWrench" pass-thru socket set. It has half the height and was able to do it. I had a 3/8 wrench. Maybe a 1/4 inch wrench would have been easier.

The second hardest was what appears to be a fuel line that bolts to the back of the Upper intake manifold to the far right (your right) close to the throttle body assembly. I think that was a 10mm. I used one of those 10mm open end wrench with a closed wratcheting end to do that (I guess you can tell that I'm a real grease monkey with these tool descriptions :).

The third was a ground wire that was behind the upper intake manifold. That can be last. I think also 10mm. When you get the two above off, you'll be able to move the upper intake manifold enough to simplify this one since the wire has a bit of play (and I mean a "bit").

Once you got the above off, front bolts, and the throttle body bolts, you could slide the Upper intake manifold to the left to move it. Keep in mind their are two bolts on the front two sides of the manifold that need removing after you take their nuts off. That requires a torx socket. Don't know the size, I improvised by forcing a 3/8 socket. Don't do that!

The other things I needed was a large enough hex socket for the front of the upper intake manifold (forgot the size). A torx socket for the lower intake manifold.

Getting the above off was the hardest part. I've seen posts of guys who felt they had to move the motors off it's mounts or getting through the engine firewall to get the upper intake manifold off. YOU DON'T HAVE TO DO THAT. After this, it was all pretty much connect the dots.

This is probably not recommended for safety reasons, but I didn't depressurize the fuel system and lost only about 8 to 16 oz of coolant during the process. If I had the right tools and did it before, I probably would have gotten done in 4 hours. Instead, because I had only one car and had to put it back together to go out and buy tools, it took me two days :(.

Oh... by the way. Don't let coolant get into the intakes. This can happen (1) when removing the lower intake manifold (hard to help this) and (2) removing the water transfer hose to replace (I recommend this, you don't want to have to go back in for anything in the near future so change what you can). If you do get coolant in their, use paper towels ad dab it all up. Some guy on some forum claimed to have engine problems after doing this job he attributes to letting to much coolant spill into the intakes.

Putting those bolts back on, good tools or not, won't be fun.

My car is now purring like a kitten!! :cheers:

Hope this helps!!!

  • 9 months later...
Posted

I had the same problem: Check Engine Light ON, Code: BAD KNOCK SENSOR

I solved the problem by adding 5 cans of "Fuel system cleaner" to my gas tank, during 5 gas fillups.

PROBLEM SOLVED!!!

Cost: About $20.00 (2 cans of GUMOUT were free after the rebates at AutoZone)

After I started having this problem, my 1999 RX300 would not shift into OD. I had to STOP, disconnect the Battery for 10 seconds, and then go.

After reading many posts on the web on the cost to replace the knock sensors (and the transmission) I decided to try ANYTHING! After adding three cans of Fuel system cleaner, the Check engine light quit comming on. I added 2 more anyway. My car has about 120,000 miles and I figured the inside of the engine (where the knock sensors are) is probobly filled with carbon deposits, these carbon deposits might be affecting how the knock sesnors work. Fuel system Cleaners claim to "Remove Carbon deposits inside the engine".

Lesson: If you ever get the Knock Sensor Code: P0330 (I think), FIRST try solving the problem with 4 or 5 cans of FUEL SYSTEM CLEANER. I also noticed that now, my transmission shifts into OD normally when the engine is cold. Before, it would take the car about 5 minutes to warm up enough for the tranny to shift into Overdrive.

TRY IT!!!! And let me know if it worked for you at mijangos1@gmail.com

Good luck,

Adrian Mijangos :)

Posted
So, a little over $300 plus 9 hours of labor.

What did Lexus want to replace them?

They quoted me a price of $1250.00 parts and labor.

Gulp! Woah, that's a lot of dough. Excellent write-up. This should be stickied as "Knock Sensors".

  • 10 months later...
Posted

Jason,

The information you've provided is very helpful. I am begiinning to perform the same job but I have one problem, how do you remove the cowling the firewall?

Hello everyone,

I just spent the last week going crazy trying to fix a "knock sensor" code P0330 on my RX300. So to save the next guy a little aggravation here is what I found out.

The dealer was trying to charge an "arm and a leg" to fix this problem (parts & labor). :cries:

Parts you are going to need:

1. Knock sensor

2. Knock sensor wiring harness

3. Intake gaskets

4. By-pass hose

5. Antifreeze

Lexus quoted me a price of $198.00 per sensor. (The car has 2 sensors, if you’re going to go through the trouble of changing them, change them both!)

After several hours of bothering the hell out of the parts guy at Lexus he told me that the part number for the knock sensor I needed was 896145-12040. I was able to order these from partsquick.com for $97.94 each. These are Genuine Toyota parts and were at my door in two days.

I ordered the intake gasket kit from rockauto.com for $56.79 this was a FEL-PRO part number MS92766 it came with all 3 gaskets.

I did order the wiring harness and by-pass hose from Lexus because I didn't have the energy to go through the whole mess again. They charged me $42.00 for the harness and $18.00 for the hose. When I got them I peeled back the Lexus sticker to reveal a Genuine Toyota sticker underneath! The Toyota part number for the wiring harness is 82219-07010 and the Toyota part number for the by-pass hose is 16261-20010. I’m sure with a little searching you can find this cheaper as well. Definitely order the by-pass hose because the hose is almost impossible to remove and I had to cut it off.

It took me 9 hours to change the knock sensors. It is not an easy job. You have to remove the whole top half of the engine.

I guess my best advice for anyone that’s going to tackle this project is to get a small 1/4" ratchet with a swivel head. I used this to get to the intake bracket mount bolts (2), as well as the ground bolt and fuel line bracket bolt that are located behind the intake, there’s not much room back there but this saved me tons of time.

Oh! and you might as well change the spark plugs cause they are breeze to change with half the engine missing.

Here are some pics of the whole ordeal. Hope this helps. Good Luck

Jason

knck sensor part number

wiring harness

by-pass hose

wiring harness part number

parts i had to remove!

engine with all parts out of the way

sensors and wiring harness with by-pass hose removed


  • 1 month later...
Posted

I have a 99 RX300 seams to be having the same problem, has anybody else tried changing the sensors? How difficult is it? Am fairly mechanically inclined and have the tools. Are there step by step instructions in print anywhere?

Thanks.

  • 5 months later...
Posted

Jason,

The information you've provided is very helpful. I am begiinning to perform the same job but I have one problem, how do you remove the cowling the firewall?

Hello everyone,

I just spent the last week going crazy trying to fix a "knock sensor" code P0330 on my RX300. So to save the next guy a little aggravation here is what I found out.

The dealer was trying to charge an "arm and a leg" to fix this problem (parts & labor). :cries:

Parts you are going to need:

1. Knock sensor

2. Knock sensor wiring harness

3. Intake gaskets

4. By-pass hose

5. Antifreeze

Lexus quoted me a price of $198.00 per sensor. (The car has 2 sensors, if you're going to go through the trouble of changing them, change them both!)

After several hours of bothering the hell out of the parts guy at Lexus he told me that the part number for the knock sensor I needed was 896145-12040. I was able to order these from partsquick.com for $97.94 each. These are Genuine Toyota parts and were at my door in two days.

I ordered the intake gasket kit from rockauto.com for $56.79 this was a FEL-PRO part number MS92766 it came with all 3 gaskets.

I did order the wiring harness and by-pass hose from Lexus because I didn't have the energy to go through the whole mess again. They charged me $42.00 for the harness and $18.00 for the hose. When I got them I peeled back the Lexus sticker to reveal a Genuine Toyota sticker underneath! The Toyota part number for the wiring harness is 82219-07010 and the Toyota part number for the by-pass hose is 16261-20010. I'm sure with a little searching you can find this cheaper as well. Definitely order the by-pass hose because the hose is almost impossible to remove and I had to cut it off.

It took me 9 hours to change the knock sensors. It is not an easy job. You have to remove the whole top half of the engine.

I guess my best advice for anyone that's going to tackle this project is to get a small 1/4" ratchet with a swivel head. I used this to get to the intake bracket mount bolts (2), as well as the ground bolt and fuel line bracket bolt that are located behind the intake, there's not much room back there but this saved me tons of time.

Oh! and you might as well change the spark plugs cause they are breeze to change with half the engine missing.

Here are some pics of the whole ordeal. Hope this helps. Good Luck

Jason

knck sensor part number

wiring harness

by-pass hose

wiring harness part number

parts i had to remove!

engine with all parts out of the way

sensors and wiring harness with by-pass hose removed

Posted

I can't begin to tell you the frustration and aggravation I have gone through to get the information you have provided. This problem has plagued me for a long time and I've already spent thousands getting the top end rebuilt due to sludge. I believe the mechanic left me a little present with the left bank knock sensor. I have decided, though to jumper the right bank to the left bank to the ecm. Hope it works. The other end of the wiring harness should be male to female and I also have been told to jumper the black wire to the white wire of the other plug. Does this sound correct?

Thanks again!

Mike Garner (RET Navy)

Posted

Well. I finally got to the Knock Sensor cable by removing the air filter assy. Can you tell me what color wire goes to each sensor? I believe there is a brown and a black. The white wires are en't used unless they are grounds.

By the way, when I looked into the intake after removing the air filter assy, there is oil in the left side puddled. Have you seen this before?

Thanks,

Mike Garner

Posted

Just an FYI, I had the same problem with my 99 RX 300. I anticipated having to replace the knock sensors and other parts.

Instead, after a little testing (moving the coils around and seeing which cylinder was misfiring) I was able to narrow it down and I replaced a SINGLE ignition coil pack and all the problems went away. Ilding became smooth, and the overdrive started to work again.

It seems the RX300 can have a coil pack fail, which then causes that cylinder to miss. The resultant vibration sets off the knock sensor (and corresponding code). The activation of the knock sensor then sets off the Lexus "limp home mode", which prevents overdrive from engaging.

You could chase knock sensors or other repairs, but in my case I was able to determine it was just one failed coil pack. Once that was replaced, the codes were cleared, and the car now runs fine 100%. Be double sure that before you go replacing knock sensors that you first deliberately rule out that you don't just have a failed coil pack causing the failure and somehow triggering the ultra sensitive knock sensor. If you don't get to the source of the problem, then just replacing the knock sensor won't solve your problem.

I said be DOUBLE SURE that you don't just have a failed coil pack and here's why: I initially had the coils individually tested, and the (voltage) test showed they were fine. But the test itself was faulty. Had I listened to that mechanic, I would have replaced a whole bunch of parts rather than just the one coil. Instead of accepting his diagnosis, I asked him to move the coils around one at a time. Each time, I would check the codes to see if it was, say, cylinder no.1 or no.3 or whatever. Within a few tries I narrowed it down to the exact cylinder no., and then replaced just that one coil. Started it back up and it was smooth as butter again. So don't just rely on a voltage/amp test. Actually physically move the coil to another cylinder, and see if that cylinder acts up.

And also:

You can get very low prices at CarQuest, lower than just about any other place I've found including Advance Auto and other places. I think I got mine for like $49, after getting initial prices of over $75 on Amazon and Advance Auto Parts.

  • 1 year later...
Posted

Hi,

I got this code p0330, hired a mechanic to get both knock sensor replaced (also the wire, and 3 gadgets). However, the check engine light still came back with same error code (I erased it twice with my check engine reader). What should I do next?

Please help!

P.S.

Don't ask me why not to talk to the mechanic, he's a friend of mine, cheap but honest. he has no clue at all, didn't charge me anything so far.

  • 6 months later...
Posted

Just an FYI, I had the same problem with my 99 RX 300. I anticipated having to replace the knock sensors and other parts.

Instead, after a little testing (moving the coils around and seeing which cylinder was misfiring) I was able to narrow it down and I replaced a SINGLE ignition coil pack and all the problems went away. Ilding became smooth, and the overdrive started to work again.

It seems the RX300 can have a coil pack fail, which then causes that cylinder to miss. The resultant vibration sets off the knock sensor (and corresponding code). The activation of the knock sensor then sets off the Lexus "limp home mode", which prevents overdrive from engaging.

You could chase knock sensors or other repairs, but in my case I was able to determine it was just one failed coil pack. Once that was replaced, the codes were cleared, and the car now runs fine 100%. Be double sure that before you go replacing knock sensors that you first deliberately rule out that you don't just have a failed coil pack causing the failure and somehow triggering the ultra sensitive knock sensor. If you don't get to the source of the problem, then just replacing the knock sensor won't solve your problem.

I said be DOUBLE SURE that you don't just have a failed coil pack and here's why: I initially had the coils individually tested, and the (voltage) test showed they were fine. But the test itself was faulty. Had I listened to that mechanic, I would have replaced a whole bunch of parts rather than just the one coil. Instead of accepting his diagnosis, I asked him to move the coils around one at a time. Each time, I would check the codes to see if it was, say, cylinder no.1 or no.3 or whatever. Within a few tries I narrowed it down to the exact cylinder no., and then replaced just that one coil. Started it back up and it was smooth as butter again. So don't just rely on a voltage/amp test. Actually physically move the coil to another cylinder, and see if that cylinder acts up.

And also:

You can get very low prices at CarQuest, lower than just about any other place I've found including Advance Auto and other places. I think I got mine for like $49, after getting initial prices of over $75 on Amazon and Advance Auto Parts.

I have a 1999 rx300 and I have a problem: When putting everything back together (after replacing valve cover gaskets), I mixed up the purge hose with the water by-pass hose. Now I have coolant in all cylinders (engine won't start).

So I had to remove all spark plugs and used small plastic hose, connected to a vacuum cleaner, to suck coolant out.

My question is: What else should I do next, before reinstalling spark plugs and everything else..... and try to start engine again?

All inputs are appreciated.

Don

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