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.