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Your Toyota Guy
Your Toyota Guy, Certified Toyota Master Diagnostic Technician
Category: Toyota
Satisfied Customers: 591
Experience:  I have been/am a Toyota technician for 15yrs+.
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I have a similar issue with a 2002 Sienna. Several years

Customer Question

I have a similar issue with a 2002 Sienna. Several years back we were told the engine light was on because of a computer issue and we left it at that since it did not seem worth the $1000 we were quoted since it was out of warranty (over 80K per this thread). However, we then moved to MD where we cannot pass emissions testing with the engine light on. The new mechanic said it was not a computer issue but the oxygen sensors. We went through the expense of replacing the oxygen sensors and the light stayed off a little while (long enough to pass inspection), but is back on and registering a catalytic converter error. I do not know the exact code. I removed the glove box as you said and saw two part numbers, 87010-08040 and 88510-?8050 (? - is rubbed off). The first is off to the left and the second is more straight back when the glove box is out. Is this the old/original part? If we were to look for a used ECM, how could we tell if it is an old or updated one?
JA: Thanks. Can you give me any more details about your issue?
Customer: That is most of it. Mainly trying to avoid another $1500 or more expense on a 14 year old van to pass the next emissions test.
JA: OK got it. Last thing — Toyota Mechanics generally expect a deposit of about $20 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Toyota
Customer: replied 1 year ago.
this was the page I referenced in regard to "original thread" by "Toyotapro"
Customer: replied 1 year ago.
Expert:  Your Toyota Guy replied 1 year ago.

Reading your description tells me definitely tells me that one of your catalytic converters is indeed bad, further more I would say that the cat is bad due to the O2 sensors being bad for a length of time, therefore not regulating the fuel to the engine properly and making the cat burn way too hot and in turn destroying the internal substrate that makes it work. Your ECM isn't bad as your symptoms don't follow the criteria for the failed ECM, not to mention your vehicle has the updated part number already. The cheapest fix would be to visit your local muffler shop and price a cat replacement with an aftermarket one. Let me know if I can help further.

Customer: replied 1 year ago.
Will the codes indicate while catalytic converter is bad? I thought I read that there were 3. When I search the part numbers I found, neither of them seems to match an ECM. It seems like the ones I saw are associated with the cooling system, so I am not sure how you can tell if it was replaced or not. What ECMs are the old/new ones?
Expert:  Your Toyota Guy replied 1 year ago.

Do you have the codes?

Customer: replied 1 year ago.
Not now. The thread I was reading indicated it was right behind the glove box and I did and since the parts numbers were right there I did not think they would be anything other than the ECM (at least one of them). I did not search them until just a few minutes ago. Where else would I look?
Expert:  Your Toyota Guy replied 1 year ago.

Ok you are trying to find the ecm part number, you do not have an ECM problem. Your problem is a bad catalytic converter.

Expert:  Your Toyota Guy replied 1 year ago.

The codes I was referring to would be the actual DTC's that someone pulled from the computer when the van was hooked to a scanner.

Expert:  Your Toyota Guy replied 1 year ago.

In your case the code would have been either p0420 or p0430.

Customer: replied 1 year ago.
I don't have those, but I will find them out. Part of your criteria for it not being the ECM was that I had the updated part number, but I now think I didn't get the right part number when looking behind the glove box.
Expert:  Your Toyota Guy replied 1 year ago.

No you pulled both a/c ecm part numbers. Can you give me your VIN number so I can check something for you?

Customer: replied 1 year ago.
Expert:  Your Toyota Guy replied 1 year ago.

Just to eliminate the ECM problem, when looking at the computers behind the glove box you are looking for one of three part numbers:


Let me know if you find one of those.