2004 Tacoma V6 Catalyst not ready

morning all.
I have a situation with the truck not passing smog here in Socal. California truck, bought it new. I installed new cats with up & downstream Denso sensors. No codes, no pending codes but still can't get the Catalyst Monitor to ready. It's been two weeks now with daily commuting.

I just found the drive cycle for an '02 in a thread. Aside from the difficulty in finding somewhere here to drive 40-55mph for 3 minutes and then 35-45 for 16 minutes without causing a traffic jam, can I do the drive cycle without an OBD scan tool? I have a scangauge II so I can see the temps come up. I live in san diego so the air temp will be above 50. Is there a way to use the scangauge to let me know if it's done correctly?

And the question from ignorance: the instructions say one of the precondition is "MIL is off" what is MIL ?
Thanks.

 

Yea the catalyst monitor typically will not run in stop and go traffic, it takes highway driving at a steady speed for awhile on most vehicles to get it to run.

I don't believe the scangauge can read readiness monitor status.

MIL is malfunction indicator light AKA check engine light.

 

The SCII will tell you if the monitors are clear (ready for inspection):


I have done it a few times, but never remember how- It's in the manual.

 

Thanks! As expected, mine is reading "not ready" after hitting scan. There's a programmable code to get a response on what isn't working:
https://www.scangauge.com/finding-incomplete-obdii-tests/ I am pretty sure my truck is a VPW protocol.
I'll try it and report back. I found a road here I think I can do the drive cycle.

 

The way I use to set the cat monitor is drive it hard at first to get cats good and hot, and then cruise steady.

 

No luck so far. I tried the 67 sticking to the instructions after work the last two days. I'll try getting the cats hot first.

 

Have you made sure your O2 and temperature sensors are all functioning properly?
I have seen skewed or failing sensors prevent monitors from running.

 

DM93: yep, both are brand new, from Denso. Also had them double checked at my mechanic.

 

I had a hell of a time getting mine to set. I did the FSM procedure for setting the catalyst monitors multiple times to no avail. Over 1400 miles later I bought a can of Cataclean (cats are aftermarket and getting old so I suspect they are near done), and then went for a ride in 4lo on a local trail. Within 5 minutes the monitors were green.

Try putting it in 4lo in some dirt somewhere for a bit and see. It was the only thing that finally set mine after months of city/highway driving didn't work.

 

Scangauge can read monitor readiness, but you have to program it in. It's a little tedious but the instructions are in the manual it comes with (also on their website).

 

Try: Disconnect battery for a minute, reconnect battery, then go for a drive. I believe the ECM needs a hard power reset.

Also, maybe try: Pull the 20 Amp EFI fuse for a minute (fuse box under hood) and it's the "same" as disconnecting battery.

My best guess.

 

I'll try 4 lo at Fiesta Island on the way home this evening.
I try the battery unplug next.

 

Be careful about unplugging the battery, that will reset all your emissions monitors and you'll be starting all over. Though if the others achieved readiness easily then it probably won't be a problem. I will be surprised if 4lo doesn't work though. The high rev'ing helps I think.

 

Ohhhh Fiesta island.

I'd only reset the ECU as a last resort. It's essentially starting over. I'd be willing to guess that something else isn't letting that monitor pass.

 

You said you installed new cat converters....are they 50 state legal ones? Asking because they will confirm during the smog test, but also because some of the cheaper aftermarket cats don't have as much of the material in them that filters the exhaust and as such might not satisfy the rear o2 sensor to set the monitors

 

I had no idea '04 changed protocol, my '01 is 9141. I had this problem last smog check. I followed the TSB exactly multiple times, no luck. I tried for a couple of weeks, wasted almost 2 tanks of fuel. I started to think my cats were bad, still running the originals.

The TSB say ECT must be 176°+. I run a 170° tstat. Was in February & that month was colder than usual. My truck was running 175°-180° during that time. Finally I decided to put a stock temp tstat in. The cat monitor set within 10 mins of driving on the fwy.

I've never had that problem before. I put the 170° tstat back in. I've had to clear the ecu since & all the readiness monitors have set fine again. Probably not gonna help you any, just sharing what happened to me.

BTW, I don't worry about resetting the ecu & having to start all over for the monitors. For my '01 (9141) all the other readiness monitors set pretty fast. The cat monitor takes the longest for me.

 

Eon blue; my new cats are the correct ones for California.
I have the standard thermostat, so it should be good. Just replaced 25k ago at 270,000 timing belt change.
Driving around in low didn't work at Fiesta Island. Too many parked cars and large drainage holes to maintain an open throttle.
I'm getting really frustrated. I've only found the protocol for the 02. Does anyone know if the 04 changed?
Thanks again.

 

For the 04, if memory serves....

- gas tank 1/2 to 3/4 full. Shouldn't be too low and shouldn't be completely full.

- open & close gas cap

- start the engine (from 100% cold, let it sit overnight)

- allow it to warm up to 160˚ minimum

- hold 3k RPM for 10 seconds (?) maybe longer


and that's supposed to do it. Don't think I'm missing any steps. It says to repeat procedure if it doesn't work. I did that probably a hundred times and it never worked for me. Can of Cataclean in my gas tank and a trip in 4lo did.

Weird that with brand new cats you're having this much trouble...mine are 50 state legal Magnaflow ones that I had installed about 6 years ago and I think they're on their last legs, which is why the Cataclean helped. Shouldn't need it with new ones.

 

I'll wake up early tomorrow and try that. I also printed out the procedures above. Thanks for the suggestions. I'll report back!