Posted on 01/22/2020 5:27:02 PM PST by Attention Surplus Disorder
I'm about to have to abandon my 2000 Toyota Avalon v6 3.0 (all Avalons have this and only this engine) with 78K miles because I can't get rid of a diagnostic "Cat not ready" message. Everything else passes fine. Car runs fine, rather better after changing the sensors. If I can't pass CA smog, I can't register the car and thus can't legally drive it.
I have: changed both upstream 02 sensors. Changed downstream post-CAT) sensor. I have gone through the following reco'ed drive cycle.
1. Make Sure the Engine Light is Off 2. Check if your Vehicle has a Coolant Temperature The drive cycle starts with a cold start. 3. Let the Engine be Idle for 2 Minutes The next step is to start the engine and keep it idle for two and half minutes, keeping >>rear defroster and AC on.<< 4. Drive the vehicle at a Steady Speed of 55 MPH Now, switch the rear defroster and ac off and keep the speed of your vehicle at 90 km/hr (55MPH) nearly for 3 minutes. During this period, the purge and Fuel monitor diagnostics will take place. 5. Decelerate your Vehicle’s Speed at 20 MPH Make the speed of your vehicle fall gradually up to 32 km/hr (20 MPH). Avoid touching/shifting of clutch or brake. 6. Again Speed Up Drive your vehicle back to 55MPH (90 km/hr) at 3/4 throttle for nearly five minutes. The catalyst monitor diagnostics will take place during this period. If the battery is detached or the catalyst is not ready, it might take five complete driving cycles to decide the status of the catalyst. 7. Stop the Vehicle Now, make your vehicle slow down and allow it to sit idle for 2 minutes.
Have done all of this. I have researched the drive cycle (and there are about four different versions all over the 'net) and done most of them several times.
Really at the end of my frickin rope.
Anyone? Yeah, I know it's a 20 damn year old car.
A small piece of electrical tape will keep it conveniently out of sight ;-)
could try an additive to clean ?
worth a shot.
https://autofella.com/how-to-clean-and-unclog-catalytic-converter/
Yeah, I had a 1988 Ford F250 truck with a constant engine light on and just covered it up so I wouldn't see it. Dealer never could figure out why it was on.
I actually do not think my cat converter is the issue, though it *could* be. The car only has 78K on it, 20 years old, the vast majority of that is in-town short hops. Maybe!
Yeah, maybe. That will be be phase 4.
1: What I’m doing, with sensors
2: elec system check
3: consider re-doing ALL replaced sensors with Denso-branded ones (*#&$^%@
4: Additives
At least that’s my current thinking, subject to change. I’ve disco’ed the batt to discharge the RAM in the ECU so now I have to drive a bunch anyway to set all the normal goobers.
Pull the fuses.
Let the car set for a few hours.
Put the fuses back in.
Have you looked in the hat?
Florida’s richest county!
Really? I did not know that, but it is a very nice area to live.
Locate and clean all (wire brush) of the cable grounding points. A bad ground can cause chaos. Nothing will make sense if something is bad.
Take that car out and run it as hard as possible.
Get the exhaust as hot as you can..
Those short runs around town are not getting the cat hot enough to burn the carbon off.
The cat monitor can take a long.. long.. time to complete and go ready.
They have no extension? They won’t allow one “not ready” monitor?
I’ve located the fuse for the O2 sensors (didn’t know the sensors were fused) and will check them in the morning when I have light. Thanks!
This. Try what Romans Nine said. Also:
https://www.youtube.com/watch?v=psIFUZaLLaM
It may be time for a new cat. They do “wear out”.
“no extension?” Naaah. Only a de facto one eg; drive around until I get a no-reg ticket. They will allow an “EVAP not ready” but nothing else and nothing else is “tradable”.
Yeah, I am getting that idea that the CAT can take a long time to go ready. Still, in my net research, I have stumbled upon half a dozen guys with 2-3 methods of getting the CAT settled in. None of those (so far) has worked, though sometimes they can take multiple attempts to work. In the meantime, FReepers have suggested half a dozen various things I can try and I shall. It’s also entirely possible that the cheap aftermarket sensors I bought are caca.
No shortage of variables here.
A, monitor “not ready” is not a failure of the cat.
It’s the computer still learning the way they work.
A p0420 or p0430 can be a failure.
Clearing codes now or unhooking the battery will put the car back to the beginging of the learning process
https://www.dropbox.com/s/4w510jbyrc5gm2n/avaloncatready.pdf?dl=0
this is from aldata for a 2000 avalon 3.0.
it’s the process to get it to run the monitor.
Good luck.
Thanks, I believe I have that from a real Toyota service bulletin.
In the meantime, I’ve removed the neg batt cable and discharged any residual NOVRAM charge, but that of course kills all the stored codes/non codes, so, back to school I (and my POS car) go!
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