2002 RX300 is Throwing Multiple Codes... P0300, P0302, P0304, P0306
01-26-22, 03:01 PM
#1
Driver School Candidate
Thread Starter
2002 RX300 is Throwing Multiple Codes... P0300, P0302, P0304, P0306
2002 RX300
Mileage Approx 277k
Timing Belt Replaced 2021 at 211k Miles
Summary: have replaced right and left solenoids, air fuel ratio sensor, and plugs on 2nd, 4th, and 6th cylinders
Two days ago as I was driving home my Check Engine, VSC, and Trac Off lights all came on. In addition, the idle became very heavy and almost seemed like the car was going to stall out. I immediately drove home (less than 5 miles) and came to this site to check the forums (all of which have been very helpful for DIY repairs in the past). Prior to this the car was operating completely normal... this came out of nowhere.
Everything I could find online seemed to indicate that the solenoids were bad and would need to be replaced. The vast majority of threads I could find said this would fix the issue. I went to the parts store, bought a code reader which sure enough, gave me code P1349, so I went ahead and replaced both the right and left solenoids. This did not fix the problem so I called my mechanic.
The mechanic showed up today and spent a few hours diagnosing. His reader did not throw code P1349, but it did throw P0300, P0302, P0304, and P0306. He took out the filter for the solenoids and cleaned them but said they weren't filthy to begin with. He seemed to think spark plugs and coils were fine. The air fuel ratio sensor was not performing as it should, so he pulled that and told me to replace it, which I did. He was confident that would be the fix. It was not. My code reader now showed the same codes... P0300, P0302, P0304, and P0306.
I went back to the parts store and got new spark plugs, because at this point, why not? Replaced plugs on the 2nd, 4th, and 6th cylinders. I reset the codes after replacing the air fuel sensor. When I fired up the engine after replacing the plugs, the check engine light does not come back on (and consequently, no codes are being thrown), but I am still getting the heavy idle at stop signs (took her around the block to test idle, see if I could get the check engine light to come back on, etc) although it does not seem quite as pronounced as before.
I am at my wits end and I don't want to just keep cascading down the parts line, because they're getting increasingly expensive. Any and all advice is welcome. Thanks in advance!
Also, I am a self taught mechanic (ha ha) so I am doing my best to use the correct terminology here, but I am happy to clarify what I am talking about with pics if needed.
Mileage Approx 277k
Timing Belt Replaced 2021 at 211k Miles
Summary: have replaced right and left solenoids, air fuel ratio sensor, and plugs on 2nd, 4th, and 6th cylinders
Two days ago as I was driving home my Check Engine, VSC, and Trac Off lights all came on. In addition, the idle became very heavy and almost seemed like the car was going to stall out. I immediately drove home (less than 5 miles) and came to this site to check the forums (all of which have been very helpful for DIY repairs in the past). Prior to this the car was operating completely normal... this came out of nowhere.
Everything I could find online seemed to indicate that the solenoids were bad and would need to be replaced. The vast majority of threads I could find said this would fix the issue. I went to the parts store, bought a code reader which sure enough, gave me code P1349, so I went ahead and replaced both the right and left solenoids. This did not fix the problem so I called my mechanic.
The mechanic showed up today and spent a few hours diagnosing. His reader did not throw code P1349, but it did throw P0300, P0302, P0304, and P0306. He took out the filter for the solenoids and cleaned them but said they weren't filthy to begin with. He seemed to think spark plugs and coils were fine. The air fuel ratio sensor was not performing as it should, so he pulled that and told me to replace it, which I did. He was confident that would be the fix. It was not. My code reader now showed the same codes... P0300, P0302, P0304, and P0306.
I went back to the parts store and got new spark plugs, because at this point, why not? Replaced plugs on the 2nd, 4th, and 6th cylinders. I reset the codes after replacing the air fuel sensor. When I fired up the engine after replacing the plugs, the check engine light does not come back on (and consequently, no codes are being thrown), but I am still getting the heavy idle at stop signs (took her around the block to test idle, see if I could get the check engine light to come back on, etc) although it does not seem quite as pronounced as before.
I am at my wits end and I don't want to just keep cascading down the parts line, because they're getting increasingly expensive. Any and all advice is welcome. Thanks in advance!
Also, I am a self taught mechanic (ha ha) so I am doing my best to use the correct terminology here, but I am happy to clarify what I am talking about with pics if needed.
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Margate330 (01-26-22)
01-26-22, 04:14 PM
#2
Moderator
I would suggest swapping ignition coils from the good side to the failing cylinders. Also do not reach for any plugs instead stick with OEMs.
Salim
Salim
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Fit1too (01-26-22)
01-26-22, 08:10 PM
#3
Lexus Test Driver
2002 RX300
Mileage Approx 277k
Timing Belt Replaced 2021 at 211k Miles
Summary: have replaced right and left solenoids, air fuel ratio sensor, and plugs on 2nd, 4th, and 6th cylinders
Two days ago as I was driving home my Check Engine, VSC, and Trac Off lights all came on. In addition, the idle became very heavy and almost seemed like the car was going to stall out. I immediately drove home (less than 5 miles) and came to this site to check the forums (all of which have been very helpful for DIY repairs in the past). Prior to this the car was operating completely normal... this came out of nowhere.
Everything I could find online seemed to indicate that the solenoids were bad and would need to be replaced. The vast majority of threads I could find said this would fix the issue. I went to the parts store, bought a code reader which sure enough, gave me code P1349, so I went ahead and replaced both the right and left solenoids. This did not fix the problem so I called my mechanic.
The mechanic showed up today and spent a few hours diagnosing. His reader did not throw code P1349, but it did throw P0300, P0302, P0304, and P0306. He took out the filter for the solenoids and cleaned them but said they weren't filthy to begin with. He seemed to think spark plugs and coils were fine. The air fuel ratio sensor was not performing as it should, so he pulled that and told me to replace it, which I did. He was confident that would be the fix. It was not. My code reader now showed the same codes... P0300, P0302, P0304, and P0306.
I went back to the parts store and got new spark plugs, because at this point, why not? Replaced plugs on the 2nd, 4th, and 6th cylinders. I reset the codes after replacing the air fuel sensor. When I fired up the engine after replacing the plugs, the check engine light does not come back on (and consequently, no codes are being thrown), but I am still getting the heavy idle at stop signs (took her around the block to test idle, see if I could get the check engine light to come back on, etc) although it does not seem quite as pronounced as before.
I am at my wits end and I don't want to just keep cascading down the parts line, because they're getting increasingly expensive. Any and all advice is welcome. Thanks in advance!
Also, I am a self taught mechanic (ha ha) so I am doing my best to use the correct terminology here, but I am happy to clarify what I am talking about with pics if needed.
Mileage Approx 277k
Timing Belt Replaced 2021 at 211k Miles
Summary: have replaced right and left solenoids, air fuel ratio sensor, and plugs on 2nd, 4th, and 6th cylinders
Two days ago as I was driving home my Check Engine, VSC, and Trac Off lights all came on. In addition, the idle became very heavy and almost seemed like the car was going to stall out. I immediately drove home (less than 5 miles) and came to this site to check the forums (all of which have been very helpful for DIY repairs in the past). Prior to this the car was operating completely normal... this came out of nowhere.
Everything I could find online seemed to indicate that the solenoids were bad and would need to be replaced. The vast majority of threads I could find said this would fix the issue. I went to the parts store, bought a code reader which sure enough, gave me code P1349, so I went ahead and replaced both the right and left solenoids. This did not fix the problem so I called my mechanic.
The mechanic showed up today and spent a few hours diagnosing. His reader did not throw code P1349, but it did throw P0300, P0302, P0304, and P0306. He took out the filter for the solenoids and cleaned them but said they weren't filthy to begin with. He seemed to think spark plugs and coils were fine. The air fuel ratio sensor was not performing as it should, so he pulled that and told me to replace it, which I did. He was confident that would be the fix. It was not. My code reader now showed the same codes... P0300, P0302, P0304, and P0306.
I went back to the parts store and got new spark plugs, because at this point, why not? Replaced plugs on the 2nd, 4th, and 6th cylinders. I reset the codes after replacing the air fuel sensor. When I fired up the engine after replacing the plugs, the check engine light does not come back on (and consequently, no codes are being thrown), but I am still getting the heavy idle at stop signs (took her around the block to test idle, see if I could get the check engine light to come back on, etc) although it does not seem quite as pronounced as before.
I am at my wits end and I don't want to just keep cascading down the parts line, because they're getting increasingly expensive. Any and all advice is welcome. Thanks in advance!
Also, I am a self taught mechanic (ha ha) so I am doing my best to use the correct terminology here, but I am happy to clarify what I am talking about with pics if needed.
Thank you for introducing your car and what is going on.
Like posted above , I agree with Salim swapping ignition coils is a good place to start and see if the codes change to the other cylinder.
I'd even go a step further and pull all the coils one by one for a visual inspection for hairline cracks and carbon tracking(looks like white powder on the rubber tips).
Might be tight but most ignition coils can be removed without pulling the manifold again and making sure the plastic coil plugs are pushed on all the way can help becuase loose plugs will misfire and idle poorly.
Highly recommend getting a scanner you can keep in the car at all times that will pull codes both current and pending -and- will also show live data like fuel trims.
Will save you money taking it to a shop for diagnosis and is very helpful because as the codes come up and see what driving conditions they are thrown.
01-27-22, 05:12 AM
#4
If the only issue he has at the moment is a "heavy idle" maybe he should clean the IACV. It's cheap and easy and certainly can't hurt.
01-27-22, 08:27 AM
#6
Driver School Candidate
Thread Starter
Oh nevermind. My mechanic cleaned the whole throttle body yesterday as well. After reading more into this, since the heavy idle is the only symptom and I don't have any issues accelerating or at speed,I am wondering if there is an air leak somewhere.
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01-27-22, 11:50 AM
#8
Driver School Candidate
Thread Starter
I am just so frustrated with all of this.
$150 in solenoids
$175 in mechanic diagnostics (which diagnosed failing AF sensor)
$200 new AF sensor which didn't solve the issue
new spark plugs
countless hours trying to research and see what the heck this could be
I don't want to keep throwing more money away on this... trying to decide if I should take it to the dealer and get their diagnostics done.
As a side note, this all happened the day after I filled my tank... could bad gas be the issue here??? I use only BP gas in the appropriate grade per the owners manual and I NEVER fill up with crappy gas. This last fill up was at BP.
Also, if the PCV was bad would I get a code specific to that or just the general misfire / cylinder codes?
$150 in solenoids
$175 in mechanic diagnostics (which diagnosed failing AF sensor)
$200 new AF sensor which didn't solve the issue
new spark plugs
countless hours trying to research and see what the heck this could be
I don't want to keep throwing more money away on this... trying to decide if I should take it to the dealer and get their diagnostics done.
As a side note, this all happened the day after I filled my tank... could bad gas be the issue here??? I use only BP gas in the appropriate grade per the owners manual and I NEVER fill up with crappy gas. This last fill up was at BP.
Also, if the PCV was bad would I get a code specific to that or just the general misfire / cylinder codes?
01-27-22, 02:50 PM
#9
Driver School Candidate
Thread Starter
Further updates. Haven't heard back from mechanic so I tried one more thing... replaced the camshaft sensor on the front bank as well... still having the same issue and the same codes (P0300, P0302, P0304, and P0306).
01-27-22, 08:10 PM
#10
Moderator
Assuming are still getting misfire on bank 2:
Misfire is spark and timing.
Since RX has VVT (oil driven advance), getting failure in one bank only points to VVT.
There can be other problems too like multiple plugs/coils failing. Timing belt getting off by a tooth or two on the cam of the failing bank. Scope on the cam sensors and crank sensor, super imposed on each other can give you lot of information and you can visually see the advance in timing as the rpm is bumped high.
Regrettably parts have been thrown [it could be that you needed regular plug replacement too, so some items may have been needed.
Put the thing away for a day, rethink the situation and if needed find a mechanic who can diagnose based on tools and techniques. Apparently your situation needs more than just read the codes and react.
Salim
Misfire is spark and timing.
Since RX has VVT (oil driven advance), getting failure in one bank only points to VVT.
There can be other problems too like multiple plugs/coils failing. Timing belt getting off by a tooth or two on the cam of the failing bank. Scope on the cam sensors and crank sensor, super imposed on each other can give you lot of information and you can visually see the advance in timing as the rpm is bumped high.
Regrettably parts have been thrown [it could be that you needed regular plug replacement too, so some items may have been needed.
Put the thing away for a day, rethink the situation and if needed find a mechanic who can diagnose based on tools and techniques. Apparently your situation needs more than just read the codes and react.
Salim
Last edited by salimshah; 01-27-22 at 08:14 PM.
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AeonFluxDl (02-03-22)
01-27-22, 08:49 PM
#11
The procedure for cleaning the IACV (Idle Air Control Valve) is in the DIY sticky:
https://www.clublexus.com/forums/rx-...ml#post3856090
But I see in a later post you are getting codes again that this wont fix.
It will often fix idle problems though.
https://www.clublexus.com/forums/rx-...ml#post3856090
But I see in a later post you are getting codes again that this wont fix.
It will often fix idle problems though.
02-02-22, 09:05 PM
#12
Driver School Candidate
02-03-22, 03:38 PM
#13
Driver School Candidate
Thread Starter
Update...
It's not the coils. I was able to swap coils 2 and 5 and am still only getting the error code on 2, 4, and 6. Also did the thing where you remove and replace the clip for the coil while the engine is running and coil 5 (after I swapped the original coil 2 into it) has a marked engine drop / rev when you remove / reinstall the clip and none of the bank 2 coils do that (not even when I swapped coils 2 and 5). So... not the coils.
Any further ideas?
It's not the coils. I was able to swap coils 2 and 5 and am still only getting the error code on 2, 4, and 6. Also did the thing where you remove and replace the clip for the coil while the engine is running and coil 5 (after I swapped the original coil 2 into it) has a marked engine drop / rev when you remove / reinstall the clip and none of the bank 2 coils do that (not even when I swapped coils 2 and 5). So... not the coils.
Any further ideas?
02-03-22, 03:40 PM
#14
Driver School Candidate
Thread Starter
02-03-22, 03:43 PM
#15
Driver School Candidate
Update...
It's not the coils. I was able to swap coils 2 and 5 and am still only getting the error code on 2, 4, and 6. Also did the thing where you remove and replace the clip for the coil while the engine is running and coil 5 (after I swapped the original coil 2 into it) has a marked engine drop / rev when you remove / reinstall the clip and none of the bank 2 coils do that (not even when I swapped coils 2 and 5). So... not the coils.
Any further ideas?
It's not the coils. I was able to swap coils 2 and 5 and am still only getting the error code on 2, 4, and 6. Also did the thing where you remove and replace the clip for the coil while the engine is running and coil 5 (after I swapped the original coil 2 into it) has a marked engine drop / rev when you remove / reinstall the clip and none of the bank 2 coils do that (not even when I swapped coils 2 and 5). So... not the coils.
Any further ideas?
DIrty, clogged fuel injector rail