Catalytic Converter Tick and P0420/P0430 Codes (1 Viewer)

[bucktownturtle]

Hola friends!

I bought my cruiser about 2 months ago and consistently after shutting off the engine, there is a ticking sound from underneath the vehicle which I assume is the catalytic converters. I have also been gifted in those 2 months (3) separate P0420 and P0430 codes for either one or both sides. I have replaced both upstream O2 sensors as I got a code for one of them shortly after I bought the truck. The down stream have not been replaced. For some reason my Torque app does not show the A/F ratio so I don't see if I am running rich.

I guess what I am wondering is if the ticking noise after the engine shut off is common? I searched and didn't see anything. Do I need techstream to check the A/F? If I am running rich causing the cats to get hot and tick, any suggestions on what could be causing that? MAF has been cleaned and plugs have been changed.

 

[Spike555]

Yes the ticking noise is normal, it is the exhaust cooling off and the metal contracting from being hot. No worries there.
Replace your down stream O2 sensors and gaskets. Those sensors do not screw into the exhaust, the sit on top of it and there is a gasket and studs and nuts that hold them in place.
If you watch the voltage on the rear O2's and they are slow to warm up and slow to react they are bad.
You can go super cheap on the rears as they do nothing other than monitor the cats, I bought two brand new off ebay for $40 with gaskets.

 

[2001LC]

Hola friends!

I bought my cruiser about 2 months ago and consistently after shutting off the engine, there is a ticking sound from underneath the vehicle which I assume is the catalytic converters. I have also been gifted in those 2 months (3) separate P0420 and P0430 codes for either one or both sides. I have replaced both upstream O2 sensors as I got a code for one of them shortly after I bought the truck. The down stream have not been replaced. For some reason my Torque app does not show the A/F ratio so I don't see if I am running rich.

I guess what I am wondering is if the ticking noise after the engine shut off is common? I searched and didn't see anything. Do I need techstream to check the A/F? If I am running rich causing the cats to get hot and tick, any suggestions on what could be causing that? MAF has been cleaned and plugs have been changed.

What is the year & mileage of your rig?

 

[vipergrhd]

Before you replace both downstream O2 sensor you can check the resistance of the sensor if you have no way to check the voltage on the sensor.
I believe it no more than 16 ohms when cold, very unlikely both downstream go bad.

 

[bucktownturtle]

What the year & mileage of you rig?

its a 2000 LX with 153k

 

[Julian Stead]

It is a good idea to invest in techstream if you are going down the route of wanting to do your own repairs. It isn’t expensive and very handy piece of kit if ever needed. Your fuel trims is a good indication to how your engine is running so being able to keep checking these is a good idea. if you are prepared to spend the money on new Cats then I would put new down stream oxy sensors in. Have a look at them first though as there is a chance the PO had these issues and went down this route themselves and replaced them.

I bit the bullet and bought a pair of CATs, lucky that I managed to buy them from a vehicle that had been donated to a college and never used on the road so they are used but good.

Check to see if the ones installed are genuine Toyota one’s, my PO had aftermarket cheap replacements put in and just didn’t last, now if you know how CATS are made then you know that they use precious metals which is why they are so expensive. I am talking Uk money here, OEM are £1200 each cheap ones are £200, this isn’t all down to Toyota greed as they make them to last, they are stainless steel and use more precious metals so there efficiency is greater.

Now you do get what you pay for, if you buy the cheapest then expect them to pass your smog tests but that is all, I wouldn’t expect them to last much longer. Some might be OE quality and are constructed in the same way in that the genuine OEM are, these would be more expensive and carry a longer warranty but might require being welding in, then you get the OEM ones that should last you another 15 years+ if your engine is running good and your not losing coolant.

Now these are the photo’s of the OEM(left) vs cheap aftermarket(right). The first thing you would notice is the weight difference, OEM is heavy compared to the other as the aftermarket one is made out if a much thinner steel, they are 3 years old and look at the flanges and how thin and corroded they are. Also there is only one CAT where the OEM one uses two. When I looked inside, the cheap one it isn’t using much of the space available at all, so even though it looks big, the insides(CAT) is small.

If you don’t have Smog Tests then I would get rid of them as they serve no real function other than to clean up the air. If you think global warming is real and is a bad thing then maybe you wouldn’t want to delete them.

 

[OffRoadRanger]

For the P0420 error code you should check for leaks in the exhaust system first, them try catalytic converter cleaner if that doesn’t solve it.

 

[bucktownturtle]

I replaced both of the rear sensors and haven't had a code since then. I started to get the code about every 100 miles on a recent trip to Baja and figured I would try replacing the rears. Seems to have fixed the problem.

 

[Spike555]

Thank you for reporting back and closing out the thread.
Now when others search and find your thread they will not just find a dead end with no solution.

 

[Burch1]

For the P0420 error code you should check for leaks in the exhaust system first, them try catalytic converter cleaner if that doesn’t solve it.

Which cleaner is good?

 

[bucktownturtle]

Well The light stayed off for a while be recently has popped back on every few weeks. I just bought a bottle of Cataclean from Amazon. I am going to try that out.

It seems I have the exhaust manifold ticking from a small leak, think that could cause the code? I never really even thought about that, and I would rather not pull the manifolds.

This guy on amazon says to try lacquer thinner to clean the catalytic converter, but I honestly would rather not pour a bunch of that in my gas tank.

 

[Burch1]

Don't forget to try a new OEM gas cap - solved my P0420 code problem

 

[nissanh]

I used scottys method and the check engine light went off for 550 miles. May be I need yo go with another gallon. Nothinh wrong with lacquer thinner as that is also made out of petrolium distillates. Its like several fule injector cleaners at once. I also bought Eastern Catalytic converter as it was 195 shipped. To my suprice, it is heavy and very well built. Flanges are thick so does the pipe. Going to give a try. Previous owner replaced driver side with an aftermarket and it is holding well for past 20K miles.

 

[nissanh]

Attached pictures are the Eastern Catalytics CAT . Flange is 9 mm and tube is 2 mm thick.

 

[2001LC]

Well The light stayed off for a while be recently has popped back on every few weeks. I just bought a bottle of Cataclean from Amazon. I am going to try that out.

It seems I have the exhaust manifold ticking from a small leak, think that could cause the code? I never really even thought about that, and I would rather not pull the manifolds.

This guy on amazon says to try lacquer thinner to clean the catalytic converter, but I honestly would rather not pour a bunch of that in my gas tank.

Tick + CAT code = check spark plug torque Spark plugs Alert Alert Alert! you may get lucky!
Exhaust leak that does not stop once engine at operating temp needs repairing or issues with CATs may arise!

 

[bucktownturtle]

So, I put the Cataclean 20 miles after the gas light went on and then drove another 20 rather aggressively before filling up 23.5 gallons. I will let the forum know if the light pops back on. I'll check the plugs, possibly this weekend. I just replaced them last year though.

 

[bucktownturtle]

I don't daily drive the car, but so far no check engine light. So far it seems like the Cataclean worked.

 

[bucktownturtle]

Little update - I took a trip from San Diego to Death Valley and put about 1000 miles on the truck and no CEL. Seems like the Cataclean works. I passed smog inspections after using this product as well.

 

[1toy]

I checked the resistance on the downstream O2 sensors. One reads in ohms 13.3 driver. And 13.1 pass. Someone said they should have 16 ohms resistance? Is this right? I am about to check the spark plug torque next. Ordered some cataclean so that will be third. Any help?

 

[VirginiaSlim]

I had a P0420 for couple months with CEL and VSC lights on. Changed engine air filter, cleaned MAF and throttle body. Did not do anything, code still showing.

Finally got a new Denso downstream O2 sensor, let it sit overnight for gasket seal, then drove around some. Codes still showing.

Finally driving today the codes are off and have remained off. Just waiting for the OBD EVAP monitor to read so I can pass emissions.

TL; DR: had P0420; changed post-cat o2 in bank 1 sensor and codes resolved.