So I picked the car up knowing there was an "intermittent" EML showing, plugged it in and it's the apparently all too common P0420, I've done some trawling and apparently the common culprits are main cat, main cat 02 sensor or air leak.
The car has just had a new main cat (PO had it done to get through recent MOT due to emissions fail) and I've done the vac trick to check for air leaks but all seems good so am I safe to go ahead and buy a new post main cat O2 sensor or is there something else I may be missing?
What sort of cat did he have fitted?
OEM equivalent or a sports cat?
If its a less restricted 100 or 200 cel cat could still give you the same code.
Also quite often the sensors do go kaput when messed with.
Is it a stock denso sensor? In the past other makes have caused issues.
Probably you'll have to suck it and see unfortunately.
What ^^^^ said.
Assuming new cat is upto the job. And no leaks. Only leaves the sensor.
And if same sensor removed out old cat and put in new cat. More than enough to upset it.
Sparkplugs.co.uk I find are reasonable. Amazon if your timing is good.
Dox0602 (double check)
Just had this fault code ping along with P0410 – Secondary air injection (AIR) system -malfunction after jet washing the car, weird.
Deleted them via torque pro and they haven't returned as of yet.
It's a cats2u cat so stock setup, the sensor is denso but it looks old so maybe the swap has upset it. I'll pop a new one on and see how we go.
It does take a good 20 odd miles (30-60 mins) of driving before it comes back on after clearing it.
It does take a good 20 odd miles (30-60 mins) of driving before it comes back on after clearing it.
Yep.
Quote from: JB21 on April 6, 2021, 17:54Just had this fault code ping along with P0410 – Secondary air injection (AIR) system -malfunction after jet washing the car, weird.
Deleted them via torque pro and they haven't returned as of yet.
Just checking. It is a 1zz engine you have?
Quote from: Ardent on April 6, 2021, 18:46Quote from: JB21 on April 6, 2021, 17:54Just had this fault code ping along with P0410 – Secondary air injection (AIR) system -malfunction after jet washing the car, weird.
Deleted them via torque pro and they haven't returned as of yet.
Just checking. It is a 1zz engine you have?
Sorry yeah, 2zz in mine.
I freely admit to a bit air fist pumping for sussing that out.
Had chance to explore the rev range?
Quote from: Ardent on April 6, 2021, 19:06I freely admit to a bit air fist pumping for sussing that out.
Had chance to explore the rev range?
Note to myself, must pay more attention. Only looked at what was posted. Not by whom. Thought was original poster. Fist pump seems a bit deflated now. Back in my box.
Change sensor. Monitor. Go from there.
On the right path.
@JB21 wrong error code mate :) Yours will likely pop up from time to time. Part/parcel of 2zz conversion
Great cheers I'll pop a new one on, where is the best place to get a new denso? Cheapest I've found is £85
Quote from: McSmallface on April 7, 2021, 06:38Great cheers I'll pop a new one on, where is the best place to get a new denso? Cheapest I've found is £85
As per above it's a Denso DOX-0206
https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0206
Alternatively https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0109 if you're OK with crimping (not soldering!) wires.
Quote from: JB21 on April 6, 2021, 17:54Just had this fault code ping along with P0410 – Secondary air injection (AIR) system -malfunction after jet washing the car, weird.
Deleted them via torque pro and they haven't returned as of yet.
Did you start the engine from cold, then shut it off again relatively quickly?
Quote from: shnazzle on April 7, 2021, 07:10Quote from: McSmallface on April 7, 2021, 06:38Great cheers I'll pop a new one on, where is the best place to get a new denso? Cheapest I've found is £85
As per above it's a Denso DOX-0206
https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0206
Alternatively https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0109 if you're OK with crimping (not soldering!) wires.
Why no to soldering?
Quote from: McSmallface on April 7, 2021, 08:45Quote from: shnazzle on April 7, 2021, 07:10Quote from: McSmallface on April 7, 2021, 06:38Great cheers I'll pop a new one on, where is the best place to get a new denso? Cheapest I've found is £85
As per above it's a Denso DOX-0206
https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0206
Alternatively https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0109 if you're OK with crimping (not soldering!) wires.
Why no to soldering?
The wires on these are coated and don't like solder. It doesn't take properly.
Quote from: Alex Knight on April 7, 2021, 07:11Quote from: JB21 on April 6, 2021, 17:54Just had this fault code ping along with P0410 – Secondary air injection (AIR) system -malfunction after jet washing the car, weird.
Deleted them via torque pro and they haven't returned as of yet.
Did you start the engine from cold, then shut it off again relatively quickly?
Indeed I did mate
Quote from: Carolyn on April 7, 2021, 08:49Quote from: McSmallface on April 7, 2021, 08:45Quote from: shnazzle on April 7, 2021, 07:10Quote from: McSmallface on April 7, 2021, 06:38Great cheers I'll pop a new one on, where is the best place to get a new denso? Cheapest I've found is £85
As per above it's a Denso DOX-0206
https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0206
Alternatively https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0109 if you're OK with crimping (not soldering!) wires.
Why no to soldering?
The wires on these are coated and don't like solder. It doesn't take properly.
Thanks for the heads up as I always solder all my connection so I'll buy one with the connector instead
Are the manifold o2s the same as the cat o2?
Quote from: McSmallface on April 7, 2021, 13:06Are the manifold o2s the same as the cat o2?
Sensors are all the same but the cat sensor has a longer lead
Ah right, I was going to suggest swapping one of the manifold o2s over to see if it throws up a code on the manifold instead of the cat to diagnose if the cat sensor was gone but if they tend to die when messed about with I won't tempt fate and remove the manifold o2
Quote from: JB21 on April 7, 2021, 10:04Quote from: Alex Knight on April 7, 2021, 07:11Quote from: JB21 on April 6, 2021, 17:54Just had this fault code ping along with P0410 – Secondary air injection (AIR) system -malfunction after jet washing the car, weird.
Deleted them via torque pro and they haven't returned as of yet.
Did you start the engine from cold, then shut it off again relatively quickly?
Indeed I did mate
Happens to me also.
The Celica ECU is looking for the secondary air pump which doesn't exist.
You can just clear the code and carry on.
Quote from: McSmallface on April 7, 2021, 13:00Quote from: Carolyn on April 7, 2021, 08:49Quote from: McSmallface on April 7, 2021, 08:45Quote from: shnazzle on April 7, 2021, 07:10Quote from: McSmallface on April 7, 2021, 06:38Great cheers I'll pop a new one on, where is the best place to get a new denso? Cheapest I've found is £85
As per above it's a Denso DOX-0206
https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0206
Alternatively https://www.sparkplugs.co.uk/denso-lambda-sensor-dox-0109 if you're OK with crimping (not soldering!) wires.
Why no to soldering?
The wires on these are coated and don't like solder. It doesn't take properly.
Thanks for the heads up as I always solder all my connection so I'll buy one with the connector instead
I know people that have soldered their 02 wires without any issues however automotive or any mobile applications are generally not soldered because it isn't vibration resistant and they can fail over time due to fatigue.
Most automotive wiring is done by using high quality crimp connectors because they are more reliable.
The crimp connectors supplied in those kits collapse making an oxygen free connection.
I've known someone who has tried soldering the wires on a Denso O2sensor: Me!
It doesn't work.
It might be the composition of the solder being used as to why it did not work for you. I have some free time and have three Denso 02 sensors. I will see if there is something about the Denso wires that doesn't take to solder.
My old Denso 02 has no issues taking to solder.
On the fist picture you can see the kind of crimp connector that comes with the Denso kit. Probably one of the best crimp connectors I have used for wiring that I bought something similar for other general purpose wiring. The heat shrink they give you are also quality.
IMG_0094.jpeg
I stripped the wires on one blue wire and one white wire and twisted them together. The wires were plenty stiff and accepted solder without any issues and I tried to pull the wires apart to test the strength, the joint is strong.
IMG_0097.jpeg
The solder I use is pretty good being lead free with good wetting properties.
However you should never solder your 02 sensor wires or any wires used for automotive use especially in high heat areas like the engine bay. Use high quality crimp connectors and heat shrink tubing to give the joint some relief.
Anyone else have strain relief/supports going to their sensor wires?
Quote from: SV-3 on April 7, 2021, 19:10Anyone else have strain relief/supports going to their sensor wires?
I add a few zip ties along the path for strain relief particularly for the the long 02 sensor running from my cat to the connector at the dipstick tube for my 2ZZ. The OEM uses those gray push in grommets along the path but they often go bad with heat and age.
Quote from: Dev on April 7, 2021, 19:30Quote from: SV-3 on April 7, 2021, 19:10Anyone else have strain relief/supports going to their sensor wires?
I add a few zip ties along the path for strain relief particularly for the the long 02 sensor running from my cat to the connector at the dipstick tube for my 2ZZ. The OEM uses those gray push in grommets along the path but they often go bad with heat and age.
The ones I have appear OEM?
They are a sort of rigid wire and attach to the 'unused' holes left and right of the engine cam cover.
Quote from: SV-3 on April 7, 2021, 19:50Quote from: Dev on April 7, 2021, 19:30Quote from: SV-3 on April 7, 2021, 19:10Anyone else have strain relief/supports going to their sensor wires?
I add a few zip ties along the path for strain relief particularly for the the long 02 sensor running from my cat to the connector at the dipstick tube for my 2ZZ. The OEM uses those gray push in grommets along the path but they often go bad with heat and age.
The ones I have appear OEM?
They are a sort of rigid wire and attach to the 'unused' holes left and right of the engine cam cover.
They probably are. I know the one behind what would be your passenger side tail light uses a grommet that goes up and over to give it relief and that is why the length of the 02 wires are long. As long as you have enough slack and no tension points I think it should be just fine. Those sensor wires are very strong.
Do the new sensors come with the aforementioned clips as all the ones on my current one are broken or hanging off
If it's vehicle specific they do from the best of recollection or the actual OEM part. If it's the universal they don't. You can use very small clear or gray zip ties as they do good job and are easy.
So the DOX-0206 just turned up and it does indeed have all the clips attached to the wire.
One question though, what type of grease do I use for the thread of the sensor? There is a little diagram in the box saying to grease the thread but the diagram only shows a tube labelled 'denso'.
Quote from: Carolyn on April 7, 2021, 17:49I've known someone who has tried soldering the wires on a Denso O2sensor: Me!
It doesn't work.
+1 ...... was right baffled at the time....
Quote from: McSmallface on April 8, 2021, 10:32So the DOX-0206 just turned up and it does indeed have all the clips attached to the wire.
One question though, what type of grease do I use for the thread of the sensor? There is a little diagram in the box saying to grease the thread but the diagram only shows a tube labelled 'denso'.
Copaslip, a very sparing amount on the male thread of the sensor.
Quote from: McSmallface on April 8, 2021, 10:32So the DOX-0206 just turned up and it does indeed have all the clips attached to the wire.
One question though, what type of grease do I use for the thread of the sensor? There is a little diagram in the box saying to grease the thread but the diagram only shows a tube labelled 'denso'.
You use anti seize on the threads as Joesson pointed out sparingly but your kit should have included a tube.
This is so when it comes time to remove its a little easier but that wasn't the case with what I dealt with last weekend helping a local member remove his which was only installed about a year ago where the owner said he used plenty of anti seize. It was so bad that even a torch didn't work and my impact gun was jamming the the 02 sensor tool and stripping the bolt. It had to be taken to a local mechanic with a lift and was an hours work with an acetylene torch.
What I am going to say next will probably be highly debatable but I will say it anyway because it is relevant. The 02 sensor post cat is different than the ones on the header even though you can substitute the one on the header which is what many owners have done including myself without any issue.
What is different about it visually is the body of the 02 sensor has a thicker bolt. This is probably done for more grabbing power because Toyota knows this needs to be heavy duty for removal. It could also be that the way it threads in and locks has enough of a tapered gap to make it easier to be undone but that is just a guess.
This is one of those instances where the devil is in the details and there is a rational for everything.
Well you're not wrong about it being a nightmare, the cat has only just been replaced a couple of months ago so the sensor must have been removed but I can't get it out for the life of me, I sprayed it with WD40 a couple of hours ago and I've heated it til it's glowing and using a proper socket but the fecking thing won't budge ...
It doesn't help that no matter what socket/extension combo you use you just simply can't get my leverage due to stuff being in the way.
Get the car up on Jack stands, as high as you can. If you have access to an angle-grinder, cut the end off the sensor, so a normal six-point socket can fit over it. Heat with a blowtorch and then use a breaker bar.
That's pretty much what you've done, I guess, but getting the car high enough should allow for a breaker bar?
I've done it this sway a couple of times.
Failing that, it will be: Get the cat off the car and attack it on the bench.
They really can be a bugger. >:(
Quote from: Carolyn on April 8, 2021, 14:47Get the car up on Jack stands, as high as you can. If you have access to an angle-grinder, cut the end off the sensor, so a normal six-point socket can fit over it. Heat with a blowtorch and then use a breaker bar.
That's pretty much what you've done, I guess, but getting the car high enough should allow for a breaker bar?
I've done it this sway a couple of times.
Failing that, it will be: Get the cat off the car and attack it on the bench.
They really can be a bugger. >:(
It's off!, I ended up taking the shroud that's above it off from inside the engine bay then cut the sensor off and put a normal socket on it with a scaffold pole on it out the top of the car then torched the hell out of it and gave it some welly and it finally went!
Then came back on here and found that's exactly what you were suggesting!
Carolyn's advice is always right. ;D
Quote from: Chilli Girl on April 8, 2021, 15:03Carolyn's advice is always right. ;D
Not always....
All back together now so I'm going to take it for a nice long run and see if we get any more codes thrown up. Cheers for all the assistance ladies and gents it's much appreciated!
So took her out for over an hour and no repeat code so I feel pretty safe in saying that the issue has been rectified.
Also on a side note the Denso (DOX-0206) came pre greasey up so didn't require any additional lubrication (it was a sticky grey coloured grease)
Was just reading the posts and was going to write that the densos come pre-greased. But you beat me to it.
I do add a bit more to the cat sensor. For reasons you now know :)
Ok so took it for a longer drive this morning and I now have 3 codes 🤣.
The original P0420 and P0172 and P0175 (which is bank 1 and 2 running too rich).
MAF sensor clean?
Quote from: McSmallface on April 10, 2021, 10:48Ok so took it for a longer drive this morning and I now have 3 codes 🤣.
The original P0420 and P0172 and P0175 (which is bank 1 and 2 running too rich).
MAF sensor clean?
Check your air filter and any constrictions in the intake system first.
Your P0420 is probably a genuine cat below efficiency which means that it could be restricted causing the system to have a constriction, this can make the car run rich. You will be looking at a new catalytic converter.
The cat and post cat O2 sensor are both brand new.
You're on the right track with cleaning the MAF, I think. Take the O ring off before you spray it - they swell up and go floppy with stuff like carb cleaner.
It is also worth taking a peek at the air filter.
Quote from: McSmallface on April 10, 2021, 13:51The cat and post cat O2 sensor are both brand new.
From my experience a P0420 is 90% always a cat below efficiency which means its not doing its job usually because of a constriction if it is the OEM ceramic cat or something up steam causing a rich condition. A constriction along the path of the air intake to the end of the exhaust can cause the engine to run rich. Less air for the amount of fuel being injected which causes the ECU to pull fuel.
You can clean your MAF or even replace it as a process of elimination but generally the MAF never gets so bad to cause this condition but anything is possible.
The other thing that can cause a rich condition is if you have a faulty fuel regulator and to diagnosis it you will have to have the pressure tested. Usually this is unlikely but it can trip the codes you are getting.
I've cleaned the maf and it's drying out in the kitchen so I'll pop out tomorrow and refit and inspect the intake and filter etc and see how we get on.
Quote from: McSmallface on April 10, 2021, 16:27I've cleaned the maf and it's drying out in the kitchen so I'll pop out tomorrow and refit and inspect the intake and filter etc and see how we get on.
Just in case....hopefully you know it's not the blob at the bottom...
Or at least not all of it.
Ok now I'm confused?
Quote from: McSmallface on April 10, 2021, 20:12Ok now I'm confused?
As was I until I found out. I believe the obvious blob is a temperature sensor. Hold the housing inverted & shine a light down inside it....the bit in there is the maf sensor.
Ahhh I get you! Yeah I cleaned the external bulb and the two little internal bits
So took the car out for 3 hours today and no codes present or pending so looks like it was the O2 throwing the original P0420 code and the MAF throwing the P0172/P0175.
Car feels miles better too since cleaning the MAF as it was filthy when it came off so I doubt it's ever been cleaned. Car feels quicker and more responsive now.
What a difference a spray makes.
Yep. Ecu now being fed better more truthful info to base its calcs on.