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.
Guy's got the same problem you do, only it's a 2004 Toyota Highlander 4 cyl with 2AZ-FE.
OKstopped their inspections years ago, with no noticable difference in air quality. However, Texas clings to this as another revenue stream. In urban areas, there may be a reason to have inspections, but in our county, where there are more cows than people, there is NO reason for annual inspections.
And you are getting a pass with all of the sensors you replaced? Reason I ask is my Acura pays hell with aftermarket sensors.
If you'd like, I could examine it myself for good leads.
I just find the good links, myself. Good at it.
Shoz wrote: “Monitor the primary and secondary O2 voltages. The primary one should swing from .005V to .0800v or so. The secondary one with a warm engine and steady driving should stay high, above .600v or so. If the second O2 mimics the first O2 swings it’s a bad cat.”
I did, I appreciate it nonetheless, thank you. I re-read it. There is a thing or two I could try on there. Also posted my Q on the ToyotaNation forum.
If it was a P420, I would have an answer, at least what I did worked on my 2012 Ford Focus.
eljefino wrote: “Toyota (camry) with that motor got a firmware update for the cat, to make the monitor less sensitive.”
Entirely a reasonable question. The replacement of those sensors cleared all the (numeric) codes I had. The OEM sensors are 7-10 times more expensive! They could still be snarking me, for sure.
I’ll tell ya how to fix it...Drive your car over to one of those BS $mog $tations and when the $mog hack sticks his head in the engine area, slam the hood down on his head. If it don’t fix it, you’ll at least feel better.
I HAVE those instructions and even worse, I’ve followed them!
Read the warranty on emissions for your car. Sometimes it is separate from the other warranty manual.
Toyota Motor Co. only issues software updates (Calibration or CAL files) for engine management and other electronic control units (ECU) only when there are specific issues or problems to be resolved. All updates are vehicle, model and model code specific. There are often additional vehicle parameters that need to be considered before selecting the correct update.
To make this process more simple, the download function requires the vehicle identification number (VIN) to be entered first. Add the relevant Bulletin ID and the system will present software updates relevant to the VIN, model & Model code.
Plus, did you check through the TSBs?
Nice! Good post!
I know it’s a Toyota but check with Volkswagen. I hear they are experts at solving emissions testing problems.
Our 2003 has that happen. Just run a small bottle of Lucas in the gas...after no more than 2 tanks the light goes out for several months.
Repeat as needed.
so I had a similar issue, look at the exact pcode. usually with some sleuthing you can determine if its upstream or downstream. if its upstream you may have gotten a defective o2 sensor. if its downstream you could have a leak between the sensors or a defective sensor or if the resistance tests on the sensors show they are likely ok, the wires may be bad, which unless your ready to run new wires to the ECM your probably best junking.
�ODB-II Monitors It's not really the distance you drive it's the way you drive it. The PCM needs to make sure all the emission systems on the vehicle are working and "ready" for operation. So you have to drive in a manner that allows the PCM to run its tests. Depending on the engine there are usually around 6-8 "emission monitors" and in most states they are all required to be "ready" in order to pass SMOG testing. Here is a drive cycle you can try to expedite the process : 1. As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. � OBDII checks oxygen sensor heater circuits, air pump and EVAP purge. 2. Turn the A/C and rear defrost off, and to 55 mph at half throttle. � OBDII checks for ignition misfire, fuel trim and canister purge. 3. Hold at a steady state speed of 55 mph for three minutes. - OBDII monitors EGR, air pump, O2 sensors and canister purge. 4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. � OBDII checks EGR and purge functions. 5. Accelerate back to 55 to 60 mph at half throttle. � OBDII checks misfire, fuel trim and purge again. 6. Hold at a steady speed of 55 to 60 mph for five minutes. � OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions. 7. Decelerate (coast down) to a stop without braking. � OBDII makes a final check of EGR and canister purge.�
Sounds like a bad terminal connection on either end or a broken wire to the downstream O2 sensor. even if the connection breaks momentarily, such as hitting a bump, it will reset the driving requirement sequence again.
Not sure what the voltage to the sensor, and back from it to the computer should be for that toyota, but I would start with checking this circuit to make sure it is sound. The sensor can’t work if the signal is not going through the wires to the computer correctly. :)
I’ll rent you my 125lb Rottweiler. Cat problem solved.
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