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.
I had a 98 Avalon that thru the P0420 code. Catalytic converter blahs blahs. There a vid on you tube on how to cheat that code. I suspect it might help you. Basically take a spark plug extension and thread it int where the sensor is taking the sensor out a quarter inch
Kansas has no inspections either
I have seen some obd2 that will hold the codes for many starts even if you disconnect the battery. Have you gone in with the scanner and cleared codes? For what ever reason dcing the battery will clear some but not all. I about ripped my hair out on that one.
I'm trying to figure out what this means to YOU. This was an Aug 2018 post - not that long ago.
Does some other means of testing apply to you [2000 Avalon]?
I’ve driven at least 350 miles, at various speeds, including 2-3 different “drive cycle” deals (and a few repetitions of each) in an effort to get this handled.
I’m not sure the word “set” is the correct term, but I do not claim to be the expert, just the bruised end user. I believe it is a “learning” process, eg; ECU has to learn how the CAT acts in response to how YOU drive the car. I have not disco’ed the batt in any of that time. I DID disco the batt 350 miles ago, but the smog tester can detect that, so even though it apparently clears any codes, the smog dudes will detect that and fail the car until the ECU relearns all it has to in order to be happy.
Regardless, I have not the slightest idea what is causing the error message. Maybe my car is a “special needs” car and has to go to a special school for problem children.
Link at #18 seems like best info you get here.
Have you tried disconnecting the battery and reattach it after like 5 minutes or so?
I have also seen where a decent sized vacuum leak made all of the O2 sensors show both sensors on both banks lean and seems like it also threw the cat code.
When I replaced the two engine sensors, I disco’ed the battery just as a general precaution against dropping wrenches onto it. That of course cleared codes (invalidly) and then 350+/- mi of subsequent driving did all the voodoo req’d for the ECU to relearn all it needs to learn to establish data for all the numerical codes. Except, apparently, for this CAT NOT READY “condition code”. At present, I have NO codes set.
No, since I have no codes (and my cheapo little scanner says that) As a result, I have not erased them.
I am thinking the touch (the disconnected) neg batt lead to the pos lead as a means of discharging the ECU NOVRAM (or whatever) may be the idea.
I sure had no bloody idea this plea for help would generate 70++ replies!
"Yes, I do know what happens, we have the same smog checks here in Texas where I live, and the vehicle can NOT be registered without passing. I know that it is extremely frustrating, I have gone through this sort of thing myself, that is how I found out about the temperature requirement.
What I ended up having to do in one case was to have the car stored overnight in an air conditioned building for 14 hours with a battery charger on it. I scouted out a route in advance with another car and practiced the drive cycle so I could be reasonably sure that I could do it accurately, then I ran a drive cycle by-the-book and all of the IM monitors went to ready. FYI, on this particular car it was the CAT monitor that stubbornly wouldn't turn ready, just like yours.
I forgot to mention, the battery condition and state of charge (as well as a weak charging system) can also keep the IM monitors from becoming ready because of out-of-range voltages."
Did you check over the alternator output and the battery state, both?
I’d take it to the Toyota dealer and have them read the codes with their fancy OBDII readers and see if they can tell you what the real problem is, even if you have to pay a little.
A wild-a**-guess would be that you need to replace the catalytic converter.
In Texas they age out at 25 years.
What????
See if you can test for one of the new O2 sensors being defective.
A fuse is a LOT cheaper than a cat converter! And I still have time to stop them before they start work tomorrow!!!!
I hope it’s what it is. Cost me $35 to find out I didn’t have enough electrical drawings. Hope you win tomorrow.
Yah, I’m thinking that the batt-alternator investigation will become phase 2. It gets to 45 degrees overnight here, I imagine that should be cold enough.
Maybe I bought & installed bogus sensors.
Thanks!
I think I am ultimately in that boat.
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