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I have a 2006 Toyota Sienna with a P0430 error (Catalyst System Efficiency Below Threshold Bank 2) . Using BlueDriver, and checking Mode 6 information, it shows a red X next to “Rich to lean threshold voltage (constant), ID: 01 02 N/A, Acceptable Range: – – 0x-80, VALUE: 0XAO”.
I watched Matt’s P0430 video several times and it was very informative. Using AutoEnginuity PC-based ScanTool (ST06-USB), I tried to look at the voltage of B2S1 vs B2S2. However, the Sienna uses air/fuel wideband sensors upstream vs O2 sensors. This makes it different from diagnosing the CAT compared to the video.
Yesterday, I took a trip to NYC and back (237 miles freeway driving). When I got home, the Check Engine light (CEL) was off. I used the BlueDriver to check. No codes. No pending codes. Also, the red X next to “Rich to lean threshold voltage (constant)” was replaced by a green check mark, and the VALUE was now 0x00.
After doing some local driving this morning, I still didn’t have CEL. I scanned with AutoEnginuity and saw that P0430 was now pending. BlueDriver again showed a red X next to “Rich to lean threshold voltage (constant)” in the Mode 6 data.
On Bank 2, with the upstream air/fuel wideband sensor and the downstream O2 sensor, how to I use AutoEnginuity to test for a bad CAT? If the CAT is bad (with the P0430 code), why would the code disappear after freeway driving?
Thanks
If I recall correctly from the wideband air fuel sensors video (might want to check that one out!) there should be a PID that emulates a narrowband oxygen sensor, but I don’t remember for sure. So far I have not had to deal with them.
I would also try to find out what conditions set a P0420/0430 on Toyotas of that year.
Are there any other conditions that would be contributing to those conditions like an exhaust leak, misfire, or burning oil on that bank? It could be that the cat is working well enough during highway cruising conditions, but not otherwise.
Thanks Apex! Yesterday, I was able to record and pull a report from the AutoEnginuity, for STFT and LTFT (for Bank 1 and 2), along with RPMs and Coolant Temperature. Looking at Short Term Fuel Trim on Bank 2, is starts off at 10.14% @ 815 RPM. As I increase RPMs, the STFT goes to the upper teens and tops out at 20.28% for the 60 seconds at high idle (2,700 RPM) before dropping back down to 7.8% @ 600 RPM.. Could the high STFT @ 20%+ be tripping the P0430? Thanks!
I’m fairly certain the P0430 would be set by what the downstream o2 sensor reads in comparison to the upstream sensor (in this case, a wideband), and would not be based on the fuel trims. However the conditions causing fuel trims could contribute to the problem.
Is the STFT/LTFT better on bank 1, or is it the same? If you have a bank 2 misfire occurring then unburned fuel will not be registered by the o2 sensor, also potentially causing catalytic converter damage. Is there any other drivability issues? What is the downstream o2 sensor reading at cruise vs WOT? I would start by looking into why you have a lean condition at high RPM, if it is bank specific that will narrow your possibilities.
Also, are these total fuel trims, or just STFT? It’s always important to look at both.
Also note, I was mixing up two bits of information on the “emulated” narrowband reading, the voltage readings are different on a wideband sensor and are in fact “made up” as explained in the wideband sensor video. I was thinking of AEM wideband sensors which have the capability of being wired in to an ECU to emulate a narrowband sensor so that you can just replace the factory o2 sensor instead of welding in another bung.
The STFT is better on Bank 1. When it gets to 20% on Bank 2, it’s only 12 or 13% on Bank 1. The P0430 code is the only code. No misfire codes. No drivability issues. The downstream O2 sensor oscillates wildly, instead of being steady.
This weekend, I plan on smoke-testing the vacuum and exhaust systems. It does look like Bank 2 is running leaner than Bank 1. Intake gasket maybe?
There were just STFT. The LTFT on Bank 1 about 8.5% at idle, and < 5% at 2,700 RPM. LTFT is a lower percent on Bank 2 than Bank 1. Bank 2 LTFT goes as low as .78% at 2,700 RPM.
Thanks!
P0420 and P0430 codes are usually pretty accurate. The cat should “consume” remaining oxygen in the exhaust stream, meaning that the downstream o2 sensor should show rich in most conditions. If you’re getting oscillation on your downstream sensor it’s pretty likely your cat is damaged.
If there has been an issue on bank 2 for a long time this could be why you have damage to your bank 2 cat, but not on your bank 1. I would definitely start figuring out why bank 2 caused damage to the catalytic converter before replacing it.
This is probably not a vacuum leak (such as an intake gasket like you suggested) because you’re going leaner at higher RPM, if it was an intake gasket you would expect to see a fuel trim improvement at higher RPM when the engine is making less vacuum (Assuming we’re only dealing with one issue here).
It’s important whenever you are looking at fuel trims that you are looking at them over a range of RPMs and adding the STFT and LTFT numbers together to get total fuel trims.
Thanks Apex! My first inclination after watching Matt’s P0430 video was that the cat needed to be replaced. Since the cat is supposed to last the life of the car, and this 2006 only has 160,000 miles, I figured something contributed to the cat going bad prematurely possibly damaging it.
What threw a wrench into this train of thought was that if the cat was physically damaged, how did the P0430 code clear itself with the highway driving? Wouldn’t it indicate that the cat may not be damaged, but possibly contaminated (oil, coolant, etc.)? Regardless, I need to find out the cause what caused the damage / contamination before replacing the cat. My next emission inspection is not until July 2021, so I have some time.
2006 Toyota Sienna Fuel Trim AutoEnginuity report2006 Toyota Sienna AutoEnginuity Fuel Trim report
The above link contains the AutoEnginuity Fuel Trim report showing STFT & LTFT for both Bank 1 and 2, RPM, and coolant temp.
Thanks for the fuel trim clarification. I appreciate your help.
thanks Apex- you said pretty much what I would have.
truth be told- I don’t really compare the S2 signal with the S1- I just showed that in the video for example.
there should never be an oscillation in the S2 so whether you have a standard ZiO2 oxygen sensor or an A/F sensor as S1, it makes no difference. the rear sensor either oscillates or not and if it does, it’s because their is no catalyst activity. (Remember even though a A/F sensor doesn’t show oscillation, it still occurs. this is evidenced on the STFT in fact).Matt, several days ago, I took the Sienna for a drive, with the AutoEnginuity connected, and viewing the Bank 2 sensors. As I was driving, the Bank 2, Sensor 2 was nice and steady – no oscillation. Does this indicate that sometimes there is catalyst activity and sometimes there isn’t? Since the CEL (with the P0430 error) disappeared after the 237 mile trip to NYC 9 days ago, the CEL has not come back (even though it has been pending for about 7 – 8 days).
Well, it finally happened today. After 120 miles since my 237 mile NYC trip, the P0430 code returned. I was able to connect the AutoEnginuity and get the Freeze Frame for DTC P0430.
Is there any information in the data that would indicate what caused the PENDING P0430 to trip the Check Engine Light?
I would suspect the cat is right on the threshold of how well it’s working for setting the code. As Matt has mentioned in at least one video that P0420 and P0430 codes are usually pretty accurate.
I guess you can only edit for 5 minutes, so I’ll just double post.
As Matt mentioned the rear O2 sensors should never oscillate, if there’s any factor besides a bad cat that is causing the rear sensor(s) to go lean you could run some live data viewing the rear o2 sensor voltages and try to reproduce it.
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