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’d be curious to know what you found out. Also, there are some “Check Engine” light problems that the only thing needed is a new OEM gas cap. Even fairly low-end OBD2 testers can test for it, but I forgot the name.
LOL (and awww)
I am at a point where I have replaced the two sensors on the exh manifolds (aka “upstream”) and the one post-CAT converter. (aka downstream) On one hand, those cleared up my numeric faults, eg; “Pxxxx”. However, I can not know if the aftermarket sensors are possibly bad out of the box. This is something that can happen with parts you buy from an ebay seller. On one hand, they must work because they fixed the numeric codes. On the other hand, they ain’t getting Mr. CAT NOT READY no matter how many drive cycles I do.
Ergo, I have decided to find a smog repair joint where I can pay 1 hour of diagnostic time (that they will no doubt complete in 10-15 mins) with the more comprehensive scanner in the hopes that the more sensitive readings (that have the actual analog voltages) will point to a more succinct problem.
I believe I have to throw limited, judicious money at it at this point, but as the car has only 78K on it, I’m skeptical that it needs a new cat converter. It drives quite noticeably better since I re-sensored but if it can’t pass smog (every other parameter passes fine) it can’t be registered. It may only be worth $3K, much less if it can’t be smogged, but it’s a perfectly comfortable and otherwise all-working car.
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