Cat drive cycle

[troyboy162]

Ya learn something new every day. I've been preemptively clearing codes prior to getting a smog ever since I had the ability to do that. I figured that even though there were no codes to clear, a clean sweep would be a good idea. What I didnt know is that resets "drive cycles" for the different components on your truck. We all know resetting the computer means the truck will have to learn adjustments again and this is a big part of that.

The truck passes the smog test but fails since this drive cycle isn't finished. Thats right, the truck blows great numbers for smog, but California chooses to fail it as of a recent rule change.

PRO-TIP: Carb approved parts and smog tests arent all about air quality, they are also about money.

The TSB attached below, outlines what needs to be done as far as driving conditions, but does not say what the computer is looking for in particular. With my truck I completed the required driving several times late last night and the drive cycle has still not changed to ready (I read it with a obd2 scanner program)

Has anyone ran into this or knows of a fix?

Ive read all over the internet and i'm not alone with the problem, but without knowing what the computer is looking for its kinda a crap shoot. A couple things that have been said on other forums

-probably not a CAT or 02 sensor problem or it would throw a code
-erratic TPS sensors causing skips have been the cause for others ( I monitor mine)
-some people take months for the drive cycle to finally complete randomly on its own.

[Seanz0rz]

You just need to drive it. No good answer on it. But yes, resetting the codes resets the readiness monitors. Otherwise it would be so easy to circumvent the check engine light check.

Do you know which system is not ready? When I bought my LX, the Evap was not ready but it still passed smog.

[troyboy162]

Its not really a function of the readiness monitors to catch people resting a CEL. I read most cars are done in less then 20 minutes and modern ODB2 systems just use a time from last reset to indicate a freshly reset computer. That's why initially you could have two or maybe even four not ready and still pass smog. Now its down to only one and some cars are only allowed the evap to be that one.

For me its the cat and evap (evap is another story lol). I've never had a CEL for the cat, my O2 sensors pass, and it smogs with good numbers. I wish there was just more info on the parameters its looking at during the drive cycle since its obviously not just better air on the output. You're right about just driving it...Thats all ive got unfortunately. I did order a coil though, since the prices are down on those I figured it was a good time to chase a super rare stumble I've had when its heat soaked. Feels similar to when my wires went bed.

[YotaFun]

Okay, I don't know what that TSB is all about, never followed it in any time I have worked at Toyota.

However, here is the way I have had the monitors to set except the evap (I'll go into that later).

Start the vehicle and let it idle till warm (usually 5-10 min will do).
Then jump in, buckle up and head to the road.
If you can, preferably get to a flat highway, it seems to help since an constant speed for a certain period of time needs to be achieved.
Once on the highway get it up to 55 mph normally (not winding out the rpms, try to keep it below 3500rpm), set the cruise control with the a/c off.
Usually within 2-5 miles the monitors will set sometimes 10-15.

I have been successful in getting monitors to set this way on majority of Toyota/Lexus models, the only one is the Sienna, don't know why, but any gen of the Sienna required over 250 miles of random driving to get to set.
They hybrids are a completely different story and usually have never had to deal with resetting the monitors on them.

Now evap, this is hard for anyone and is easier if your in a more mild climate or have a garage that you can sorta of regulate the temperature in.
Ideally you will want to have the tank at 1/2 full (1/4 or 3/4 will do but completely full or empty will not).
If you can park the truck in a place where the temperature can remain anywhere between 70-90 degrees Fahrenheit, over night the evap system will usually run its cycle and reset.

On new Toyota/Lexus (05+ on majority of the models) can be Reset quickly using Toyota's Techstream, but on the older ones, usually if we left them in the shop overnight they would reset)

Hope this helps a little, as far as the parameters it needs to see I haven't looked too much into it except for the Evap system since that seems to be the most prone issues I have had here in the Northeast.

[toyotech]

OBD 2 vehicles don't even run a sniff test. If the monitors all pass. Or like you said they allow one to not ready yet and still pass. This is all that is done now. Jist smogged my tundra and it took 5 mins

Your just gonna have to drive the vehicle. It has to see two key cycles also. Some evap systems don't actually run till vehicle is off and sat over night with the right conditions which is unknown since its up to the ecu.

[Seanz0rz]

Pre 00 cars still require the dyno test. Or at least my 98 still requires it. Tests also vary depending on location. And on how your vehicle has performed in the past.

[troyboy162]

Yup, we get the whole enchilada being early obd2 vehicles. Lucky us...

[troyboy162]

Avy thats interesting. According to the Tsb your drives shouldn't have worked, but I can honestly say the Tsb isnt telling what's really going on so the details it has are probably, just to get you out driving instead of circles in the parking lot.

[toyotech]

Yup, we get the whole enchilada being early obd2 vehicles. Lucky us...


Pre 00 cars still require the dyno test. Or at least my 98 still requires it. Tests also vary depending on location. And on how your vehicle has performed in the past.


Ah. Both my OBD2 vehicles are newer than 2000.

[4x4mike]

I think that it was Paddlenbike that has brought up drive cycles up in the past. The search can't seem to find it but part of the mushy space in my brain seems to remember he outlined or linked some info. I'll look.

[troyboy162]

I've googled it a bunch. There are some genaric drive cycles on places like ask.com, but when the TSB dosnt work and Avy used his own recipe at work, I think I'm just in for a long stint of driving lol.

[YotaFun]

Troy, have you given my method a shot yet? I mean if it works out should take no more then 20 min to complete :-)

[troyboy162]

Yup every chance I get! I don't have working cruise control, but with these long desert roads I can hold 55 well. Ice gotten 500 miles on the truck since this started.
Couple things I am wondering is maybe my gearing and tires are giving it unexpected rpm for a given speed.

I've driven 55 per the trucks speedo and also GPS corrected 55. I haven't given up, I'm just not optimistic lol

[YotaFun]

And it still won't set the monitor? That is very strange....

[troyboy162]

still hasn't... I wish I knew what it was looking for. Its obviously wanting some combination that mine just wont produce. There is other stories on the internet like this, but I was hoping to get this done this week.

I might have a better chance hooking up my evap and getting that one to pass.

[toyotech]

Which monitor won't pass? I know some monitors won't pass or start if there are emissions issues.

I seen small exhaust leaks keep a monitor from passing.

[4x4mike]

500 miles and still not ready! I assume your truck will do faster than 55 mph? Take it up higher for a bit. I doubt the CC has something to do with it but perhaps the higher speed combined with the increased operating temperatures will help as you've probably turned it off and on enough times.

[Seanz0rz]

I can personally vouch for it being able to do more than 55. Much more.

[troyboy162]

its anyones guess at this point. I'm just driving it every day to work and that includes long sections of 55 and some 70. She's got all the evap set up and headed to the garage for tonight

[Seanz0rz]

What code reader do you have? Mine has the icons at the top for which emission systems are ready or pending.
https://farm8.staticflickr.com/7485/26866761352_102a70cde6_b.jpg (https://flic.kr/p/GW8b8j)

My Bluetooth dongle via Torque App also has a screen that will tell you whats go/waiting/no go

[troyboy162]

I have the scantool.net one. Its really old but still newer then my truck lol.

[Seanz0rz]

Let me know if you want to borrow mine.

[troyboy162]

800 miles and the cat monitor is still not good but I passhed by getting my evap to be ready. 96-99 is any one monitor. 2000 and up is only evap allowed.

[Seanz0rz]

Yay! Glad it passed and good to know about the monitors.

[troyboy162]

yeah that's crazy that they make any distinction between the years like that, but somehow my old, boiling gas flooded, charcoal canister is working enough to give the ECU whatever it needed to see.

I'm still clueless on the cat monitor. The guy mentioned there are three things going on in there and maybe the cat wasn't working well enough on one of them. If that were the case I'd imagine not passing smog or at least throwing a emissions related code. Of course I still really don't know jack about whats going on, or most importantly what the computer needs to see for that monitor. I will check again in a few months and see if its set.

[Seanz0rz]

Post up your numbers from the report. Those give good indications on what may be wrong.

[troyboy162]

They are out in the truck right now but do cats go bad, not throw codes, and still pass smog?

[Seanz0rz]

Mine was on the edge of death for years. I barely passed smog the two or 3 times before I replaced it. After the new cat I passed with flying colors.

[YotaFun]

I have seen where o2 sensors slowly going out will make things act funny, they aren't out enough to throw an emissions code, but are out enough to cause some monitors not to set.
Usually however you will notice a dramatic change in fuel mileage or vehicle performance, in my truck, my gas mileage sunk, where are that point I might as well have said I was driving a hummer, and besides the injectors going out the truck just was all around super sluggish...

The year difference is weird, I will have to double check, I can't remember it it was 99 or 00 where the front o2 sensor changed to an A/f sensor and the tolerances for emissions tightened up a little bit.

[troyboy162]

hmm interesting info Avi. My truck has been a dog ever since I bought it so I haven't noticed any decline. My O2 sensors are certainly in overtime though. A precat 02 sensor would make a nice birthday present for her.

Driving the truck hard the last few days to work did show me I had a issue. The rare stumble I attributed to maybe a coil became easy to reproduce by using lots of throttle in a high gear up a hill. I checked the plugs and they were very warn. After I replaced them ithe stumble is gone. The rare surging I thought was my toque converter appears to be gone as well. I wonder if that was the problem with my readyness monitor since I bet fuel probably wasn't burning that great.

The plugs looked good when I rolled the truck a few years ago, but they were certainly past due now.

[paddlenbike]

The year difference is weird, I will have to double check, I can't remember it it was 99 or 00 where the front o2 sensor changed to an A/f sensor and the tolerances for emissions tightened up a little bit.

It depends on whether its a CA or federal emissions truck. The 99 and 00 CA models use a wideband AFR sensor, however a 00 federal emissions model (like mine) still uses the older style narrowband O2. By 2001, essentially all models were like CA models.

[YotaFun]

It depends on whether its a CA or federal emissions truck. The 99 and 00 CA models use a wideband AFR sensor, however a 00 federal emissions model (like mine) still uses the older style narrowband O2. By 2001, essentially all models were like CA models.

Thank you for the clarification! I am curious now what my 00 4Runner now.

[4x4mike]

The year difference is weird, I will have to double check, I can't remember it it was 99 or 00 where the front o2 sensor changed to an A/f sensor and the tolerances for emissions tightened up a little bit.

FWIW, my California emissioned '99 has an air/fuel sensor up front. When it went out it threw a code. Prior to that I hadn't noticed any change in mileage or performance. Changing the sensor cleared the code and gave me great mileage that eventually tapered back to normal.