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CODES: P0354 Ignition Coil 4 “D” Primary / Secondary Circuit.
The next day, after reaching home, codes P0300-P0306 were also there but marked as 'Pending'. P0354 was marked as 'Confirmed'.
SITUATION: Noticed engine stuttering and check engine and V SC lights on after stopping midway on 200 mile drive home over the Sierras. Elevation change from 4000 up to 8000 down to 800 feet.
Turned off car at ~ 150 miles due to a standstill on the freeway. Turned the enginge off-on 3 times in within ten minutes.
Stopped for gas and food shortly after this at 160 miles.
After stop, drove 1 block, felt a slight stuttering from the engine and noticed check engine light was on.
Opened hood, cleaned up some white powder off the battery. It was around the covers of battery cell refill holes. Removed the covers and cleaned up powder taking care it did not fall into the holes.
Also noticed there was a trail of large water drops, along the arc I took to park and under the front center - passenger side. It looked, felt, smelled like plain water.
Checked codes using a generic Bluetooth OBD2 dongle with the Car Scanner app. Looked up code on the internet, drove 1 block to Walmart service center to inquire fruitlessly, then drove home 35 miles at 55mph. Did not notice any more stuttering.
Next day: Checked and Reset the codes. Idled it for 15 min then drove around the block. Codes did not come back. Replaced air filter and cabin filter.
PLAN: Drive. If the light comes back on again, stop and switch Ignition Coils 4 and 6. If the code location changes, stop at the parts store, to replace the ignition coil.
RX History: Bought 2007 RX in 2020 with ~96k. After 1 year, still under 99k, due to reduced driving. No issues besides battery drain problems. Only driving only on weekends, and not every weekend. I replaced the battery, but it still falls below 12.2V after sitting a few days.
Dealer service up to ~70k. After that just oil and filter changes by local mechanic. Water pump and belts replaced by local mechanic at 95k due to leaking. Significant labor for rear access, but did not replace any spark plugs or coils. Transmission fluid has never been replaced. I intend to have it replaced soon.
Fuel: Original owner sometimes used regular gas. I used premium up until just a month before this trip.
QUESTIONS:
Do I need to reset the codes after switching the coils?
What is the likelihood that other coils will fail after this? Buy 1 coil or a whole pack?
How bad is it to be driving with those codes? I need to drive about 20 miles each way tomorrow. If the code comes back should I stop at parts store and replace it immediately, or can I come home and order?
Is there a separate code for a spark plug malfunction?
If the code location changes after switching, this would seem to rule out the spark plug. Making it most likely the coil is bad. Could it still be a wiring issue? Or a bad coil driver circuit or PCM/ECM? I read those are less common issues.
Could the non-premium fuel have contributed to this problem? Especially given the long steep climb with curves?
What could the water have been coming from?
Could this be related to the white powder/sulfate/acid on the battery?
RELATED INFO FOR FUTURE READERS found in others threads and sites
[Please offer any corrections or clarifications.]
The PCM (control module] commands the ignition coil packs and monitors them for malfunctions. The PCM sets an ignition coil control circuit diagnosis code P0351-P0356 when it detects a problem with the ignition coil circuit.
The ignition coil pack is used to convert the low primary circuit voltage to high secondary voltage needed to fire the plugs. The PCM triggers the primary circuit of each coil. If the PCM doesn’t see the primary voltage spike that indicates the coil fired, it diagnoses a problem with the coil pack. If the secondary part of the ignition coil is shorted out, the primary spike will be weak as a result. That’s when it typically sets a P035x code.
Resolving P035x code will typically clear P030x as well. Misfiring can lead to a lack of power, and/or engine hesitation. It can also harm the catalytic converter. You vehicle may idle rough if a cylinder isn’t getting enough spark. You may smell raw fuel.
The last digit of these codes references the cylinder where the issue is occurring.
The letter coincides with the cylinder, i.e., A = #1, B = #2, C = #3, etc.
Diagram of the cylinders:
1 3 5 rear
2 4 6 front
The front cylinders are easy to access.
The rear is complicated and labor intensive to access.
P0351-P0356 codes occur when the coil for that cylinder fails to send a feedback pulse to the ECM signaling a successful ignition spark.
Most common causes of a P035x code: Wiring Issues (short, open, or bad ground). Loose connection at the coil. Bad Coil Pack. There is a 10 digit number on the coil itself, which you can use to find a replacement. Least likely: Bad PCM.
Troubleshooting a P035x code
I. Inspect the electrical connector and wire harness for any loose, broken or damaged wires. Try wiggling and testing the wiring at the diagnosed coil and along the wiring harness to the PCM. Check that the contact in the coil connector is secure. Make sure the wire bundle is not rubbing against anything. Look anywhere that the harness bends or touches anything sharp. Look to see if it looks burnt anywhere. Check for damage and repair the wiring accordingly. If no problems are found, most commonly, the ignition coil will need to be replaced.II. Optional/advanced: Voltage tests and spark plug inspection
III. Swap Test the fault location coil pack by swapping it with another coil pack. If the misfire moves to the cylinder with the swapped coil, then it appears the coil pack is the problem, not the control circuit. If however, the misfire remains on the same cylinder, you know the control circuit is to blame. If the code failed to move, then it is likely you either have an issue with the wiring going from the coil pack to the PCM. If the misfire is intermittent, jiggle the wiring harness and see if it has an impact on the way the engine is running.
How to remove a coil:
You need a 10mm socket.
Pop hood and remove engine cover. Pull it up gently and it pops off.
Unclip the wiring connection to the coil. If the clip is stuck, you may need a clamp or pliers. Be careful not to break it. Allegedly, once you put enough pressure on it, it releases and slides off easily.
Use the 10mm socket to remove the bolt on the coil.
You pretty much nailed it.
Also you asked a lot of questions so I'll take a couple and leave some for others who want to jump in.
#4 from above: "Is there a separate code for a spark plug malfunction?": No,
As you have already figured out the P000 to P0306 are generic cylinder misfire codes that can be caused by a variety of things like listed below(and more).
A bad spark plug could cause these codes but so can many other things and there is no specific code for a spark plug unfortunately.
From my long saga from failing coils I recommend doing a visual check on all coil packs on the front bank where you are having problems.
Looking for hairline cracks and signs of arcing from carbon tracking- carbon tracking looks like white powder on the coil's rubber end where it sits onto the plug and it causes arcing on the engine and this may throw a generic cylinder code.
Thank you for the picture Margate. Mine looks nothing like that. No cracks, signs or arcing, nor any white powder on the coil pack.
In the previous episode, after reaching home, I had merely reset the codes and changed the air filter, and made sure I had a 10mm socket and pliers in the car.
The light did come back, but not until after about 40 miles of driving, mainly freeway. Made a few short stops for shopping. After starting the 5th time and driving a few miles, the light come back on.
Same codes as before: P0354 and P0300 - P0306. After finding a parking lot, waited for engine to cool a little, and switched ignition coils in cylinders 4 and 6. Number 6 looks like a newer model coil. I did not look at the coil in cylinder 2 yet. Then cleared the codes again. Drove another 15 miles home on a mix of surface streets and freeway. The light has not yet come back on. I expect it will, just waiting to see if the code location changes.
Tip: The clips were difficult to release. The pliers were helpful to apply enough downward pressure on the clip lock, so that it does not break the clip when you slide it out.
There were water drops again under the car, in the same location, under the front passenger side. Unfortunately, I did not think to look for this on the previous stops. I only checked after pulling over after the light came on to swap the coils.
My Car Scanner app says "Reseting codes is not a method of troubleshooting." I thought I needed to reset the code after making a change, such as swapping coil packs. Or will they reset themselves?
What is the likelihood that other coils will fail after this? Buy 1 coil or a whole pack?
How bad is it to be driving with those codes? If the code has not yet returned but almost certainly will could I still be doing damage?
There is no separate code for a spark plug malfunction. After swapping the coil pack with the error code with another pack, if the code also swaps location, then I can conclude the coil pack is faulty. If the location does not change, then it is likely a wiring or connection issue. Alternatively, could it also be a bad spark plug?
If the code location changes after switching, this would seem to rule out the spark plug. Making it most likely the coil is bad. IMU, it is not likely to be a wiring or PCM/ECM issue in this case.
Could the non-premium fuel have contributed to this problem? Especially given the long steep climb with curves?
What could the water on the front passenger side be coming from?
Could this be related to the white powder/sulfate/acid on the battery?
Any answers or other advice welcome.
Last edited by Luv07RX350; Dec 5, 2021 at 04:38 PM.
Reason: clarification
The P0354 is a cylinder $4 specific coil code as you aleardy know.
Swapping it to cylinder #6 should hopefully change the code to P0356- if so, it is usually safe to say you have a coil problem and replacing it should hopefully clear the other generic cylinder codes too.
These coils can fail in ways that can throw off other cylinders and throw generic codes too that can move around to other cylinders inconsistently and intermittently.
Your using the air compresser w/ the defroster/heater being on which causes the water. Also Being near 100k, I swap out the plugs as well as the bank 1 coils, as well as the rear diff oil & transfer case oil as well as the trans fluid & filter which gives the mechanic to clean the two magnets in the pan. You also should be running premuim fuel as well.....FYI when you need brakes next= A great cost effective upgrade is to do a gen3 upgrade.....A set of gen 3 pads, rotors & a pr of reman calipers, which is a direct bolt on for better longer lasting stopping power. I used the Wagner oex 1324 pads w/ a pr of Bosch rotors & a pr of reman '12 rx calipers. I also swapped out the oem brake hoses for a set of SS hoses as well as flush out the old brake fluid for new dot 3 fluid. You'll find the pedal is slightly firmer w/ less travel.
Thank you both. I'll try to run some errands soon with "hope" of triggering a code.
I was concerned about the water, but it's not like I ever looked before this. I do trust my mechanic but it never feels good going in with mystery problems. Small things I prefer to do myself rather than the time and hassle of getting back and forth.
I'll try leaving the climate control off. I didn't turn on heat or defrost the other day, but the climate control may have been on. I dislike the controls on that. You have to use the touchscreen to get it to just use the fan without A/C.
I want to keep the car as long as possible, so I do intend to have all that work you mentioned done. As we only drove a couple thousand miles last year, it seemed better to wait on the fluids until we'd be driving more. Maybe that is the wrong logic? We mostly go nearby, but wouldn't want to be stranded on one of our longer trips. I hadn't heard of the gen3 brake upgrade. I am due for brakes soonish. I will definitely look into it. I don't know if my indy mechanic will work with remanufactured parts; maybe if I provide them, but then no warranty on the work, I think.
If I go ahead and have all the the spark plugs replaced, then would it be prudent to also have the 3 rear coils replaced? [Edit: oops, I see you did suggest doing the rear coils with the plugs!] My mechanic only does OEM parts and the prices are a little inflated so I guess the coils would be an extra $200-300. Of course the labor to get back there is more than that, so better not to pay that again.
After buying the car, I called the previous mechanic who replaced the water pump at 92K, to find out what had been done. He said had to remove the engine! I wish he had suggested new plugs etc. I suppose he didn't want to be seen as inflating the work.
Last edited by Luv07RX350; Dec 5, 2021 at 09:46 PM.
Interesting similarity with my 07 RX. Bought the car with 95.9K miles and headed out on a road trip 3 days later. Got to Denver and one of my ignition coils decided to fail... uncanny.
Thank you both. I'll try to run some errands soon with "hope" of triggering a code.
I was concerned about the water, but it's not like I ever looked before this. I do trust my mechanic but it never feels good going in with mystery problems. Small things I prefer to do myself rather than the time and hassle of getting back and forth.
I'll try leaving the climate control off. I didn't turn on heat or defrost the other day, but the climate control may have been on. I dislike the controls on that. You have to use the touchscreen to get it to just use the fan without A/C.
>>>When its on the cooler side, you'll find it dehumitafies/defrosts the windows
I want to keep the car as long as possible, so I do intend to have all that work you mentioned done. As we only drove a couple thousand miles last year, it seemed better to wait on the fluids until we'd be driving more. Maybe that is the wrong logic? We mostly go nearby, but wouldn't want to be stranded on one of our longer trips. I hadn't heard of the gen3 brake upgrade. I am due for brakes soonish. I will definitely look into it. I don't know if my indy mechanic will work with remanufactured parts; maybe if I provide them, but then no warranty on the work, I think.
>>>All the shops, including dealers use reman calipers. Its one thing if its a new vehicle under warranty. Also a good possiblity your shop has no idea about about other years vehicle upgrades that'll work on your car. I used Wagner oex1324 pads,Bosch #50011479 rotors w/ Brake best reman calipers from oreillys #19b6274 for the lest & #19b6275 for the right. You also use #19b3352 left caliper & #19b3353 for the right caliper. Either set will work. Basically its whether its a Japanese or Candian bbuilt vehicle which doesn't matter. Since your there you could also replace the oem brake hoses if needed, for sure have the old fluid flushed out. btw this is a direct bolt on & also the B iis for the caliper brackets which you'll need. Have the shop put your old calipers in the box to get your caliper cores back.
If I go ahead and have all the the spark plugs replaced, then would it be prudent to also have the 3 rear coils replaced? [Edit: oops, I see you did suggest doing the rear coils with the plugs!] My mechanic only does OEM parts and the prices are a little inflated so I guess the coils would be an extra $200-300. Of course the labor to get back there is more than that, so better not to pay that again.
After buying the car, I called the previous mechanic who replaced the water pump at 92K, to find out what had been done. He said had to remove the engine! I wish he had suggested new plugs etc. I suppose he didn't want to be seen as inflating the work.
Some drop the cradle w/ the engine to get to the w/p & some don't. Wow, it would have been super easy to just replace the coils/plugs, oh well some only do what you ask & don't seem to mention, by the way since your here, we can do this or that. Wonder if the previous mechanic replaced the t-stat? Since he replaced the w/p...Sounds like you need a shecanic, which I've worked w/ a few strong women techs before........
The light came back on. The code did move to P0356, so it appears the coil is at fault. I may just replace it myself for now. I will get some estimates on the other work. Never ever seen a she-canic here, but I do have a few choices who started out at Lexus or Toyota.
I don't remember any mention of replacing the thermostat.. is it usual to do that along with the water pump?
More questions..
1. Is NGX better than Denso?
2. Is it also recommended to replace the VVTi and oil cooler lines with metal lines? Is this covered by a recall? If so, do I have to go to a dealer for this? I emailed the nearest dealer to ask this a few months ago, but they never responded.
3. Will upgrading to the gen3 brake system have any impact on the ability to make small modifications in tires or struts in the future for off-road / forest-road driving?
For the 07 RX, NGK ignition coil seems to be out of stock most places, so seems DENSO is the standard choice. DENSO 6731309 is $51.79 Rockauto. Ebay $33-39 well-rated seller vsl-auto. $26.86 ebay seller ken7735, but a few reviewers not receiving product.
NGK 48726 $123ea AdvancedAutoParts -25% with four. $68 Summitracing special order
Last edited by Luv07RX350; Dec 17, 2021 at 10:11 PM.
Reason: adding link to another seller
[QUOTE=Luv07RX350;11183980]The light came back on. The code did move to P0356, so it appears the coil is at fault. I may just replace it myself for now. I will get some estimates on the other work. Never ever seen a she-canic here, but I do have a few choices who started out at Lexus or Toyota.
I don't remember any mention of replacing the thermostat.. is it usual to do that along with the water pump? Yea since the coolant is drained, good time to change out the T-stat as well......
More questions..
1. Is NGX better than Denso?>>> No, Just another good product, similar to AC Delco & Motorcraft....
2. Is it also recommended to replace the VVTi and oil cooler lines with metal lines?>>> I recommed do it, as you don't have to worrry about when a hose is going to rupure. Is this covered by a recall? If so, do I have to go to a dealer for this? I emailed the nearest dealer to ask this a few months ago, but they never responded.>>> I really wouldn't hold your breath on getting back to you about this......
3. Will upgrading to the gen3 brake system have any impact on the ability to make small modifications in tires or struts in the future for off-road / forest-road driving? >>> Yea, You'll have impoved braking.....
Is there any harm in just replacing the front spark plugs and coil for now? I will do the rest at my next oil change after I get answers and estimates on all that needs doing. I'm hardly driving right now. I called the previous dealer about service history on the oil cooler lines, but no call back from technician yet. Same thing happened when I tried to call earlier in the year.
I def want to replace the ignition coil before driving anywhere. I should have mentioned that after switching the coils, it took several miles before the check engine light, came back on, but once it did, it flashed briefly. I read flashing can indicate fuel overflow which can damage the catalytic converter.
At 60k in 2016, the power steering and brake fluid were flushed and the rear diff oil & transfer case oil were serviced. It has not done any towing since then. Now < 99k. Would the rear diff & transfer case service likely be needed again now?
P0354 Ignition coil
I do trust my mechanic but it never feels good going in with mystery problems. Small things I prefer to do myself rather than the time and hassle of getting back and forth.
