Help. Catalytic monitor not setting.

Joined
Apr 29, 2017
Messages
138
Location
Orange County CA
2002 Toyota Sienna 229,500 miles, California Cat smog setup. Been trying for 6 months to get the catalytic monitor to set.

OBD Codes = 0. Non-related to emissions or anything else.

Went online and found the official Toyota drive cycle patterns. One that I'm pretty sure is for my car and the other one that may be for my car, so I did both and have repeated them at least three different times in different weeks and months. I actually did more, but I would swear in court to three.

In July and two weeks ago treated the fuel with Cataclean strictly following the instructions. And of course there's been a lot of mixed long and short driving under freeway or service street conditions since then.

I even went on YouTube and tried different suggested "tricks" from the sages there that they swear will force your catalytic monitor to set, but that did not work either.

I have no particular odd sounds coming from my engine or from the exhaust and the exhaust smoke doesn't look any different than from over the last 10 years I've had the car. I use Castrol high mileage oil and try to change the oil every ~5,000 miles.

My spark plugs are Denso iradium long lifes with 26,000 miles on them. I checked the even cylinder front ones and based on pictures of what decent plugs should look like they seem to have no particular wear or fouling on them.

The only thing wrong with the system is my Evap is kind of shot. I do not get the whoosh sound when I undo the fuel cap and of course that monitor is not set. But in California that doesn't matter.

Sorry this is so long, but I tried to anticipate any questions somebody might have. Now I'm looking for any thought as to why it may not be setting and suggestions to get it to.
 
I take it you've found the official toyota pdf.

What's up with your EVAP, is it throwing a pending code? I'm finding it hard to believe it's "shot", but not generating codes.

It might work if you put in a rear 02 spacer, to help it "decide" the marginal cat is actually good. Then take the spacer out again.
 
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Been trying to get past this one on a 2000 Camry for a few weeks now... Been checking it every day that the car is driven... Went to the store a couple of miles away and back in cold weather yesterday and all of a sudden it's now ready. I have no idea why all of a sudden a short trip like that did it, but it did.
 
Have your battery and charging system checked. Proper voltages are critical to the system functioning correctly. A few years ago I had a Tahoe that wouldn't set all of the monitors. It turned out that the battery was bad even though it was only 2 years old, it started/ran fine, and did so for several months (including the day that the battery was replaced).
 
I had a similar issue on my Mazda. My battery negative terminal rotted off and reset the computer a couple weeks before my inspection was due. The shop wouldn’t give me a sticker saying I had “not ready” codes. It took a while to reset and it finally did after a ~300 mile trip for work. How many miles have you put on in those 6 months? Any highway trips?
 
Been trying to get past this one on a 2000 Camry for a few weeks now... Been checking it every day that the car is driven... Went to the store a couple of miles away and back in cold weather yesterday and all of a sudden it's now ready. I have no idea why all of a sudden a short trip like that did it, but it did.

I probably should have mentioned that I have emissions due soon on this vehicle, hence the apparent OCD in daily testing for emissions status.
 
Thanks everyone for your thoughts. I've been waiting a couple of days to let the thread populate before I jumped back on back on.

I average ~800 miles a month of fairly mixed driving. As mentioned did find and use the official Toyota drive cycle patterns, strictly, several times over. Including the secondary one that probably wasn't exactly for my car, but what the heck.
My battery and charging system seems to be fine. Battery holder charge well and alternator has normal output.

Yes, absolutely no DTCs over the last 6 months. The only thing I have related to the Evap is that it, like the Cat monitor, is reading incomplete. But it's actually been like that through for several years. Even replaced the gas cap to see if that was the reason for some leak. Nope.

Well, thanks everybody for your thoughts. I'll check back a little later to see if there's anything new. I guess there's nothing for it except to spend the money to have it diagnosed.
 
If you've gone months without these setting you may have a prerequisite problem like a cold running thermostat.
 
Does Toyota have manufacturer specific codes and does your code reader support them if so...
I'm not sure I understand the question. My code reader is a cheapy one but my mechanic doesn't feel that he is more advanced one would show anything different. Are you saying that it might?
 
I'm not sure I understand the question. My code reader is a cheapy one but my mechanic doesn't feel that he is more advanced one would show anything different. Are you saying that it might?

Some manufacturers have "Manufacturers specific" or "Enhanced" codes. Honda/Acura does I actually think almost all manufacturers do, but i do very little with Toyotas. At least way back in the day cheaper scanners wouldn't always pick these up and i chased a similar problem on an Acura because my cheap scanned wasn't reading a pending Manufacturere code. I think it was an EGR lift code, but it was a long time ago.

Anyway i would start by seeing if the documentation for your hardware mentions anything and also trying to figure out if it was a ting on your make and model.
 
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