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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
Satisfied Customers: 4682
Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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2005 Toyota Sienna: Van..warning lights..check engine, vsc and TRAC

Resolved Question:

I have a 2005 Toyota Sienna Van. Three warning lights on the dash are on together from time-to-time: check engine, VSC and TRAC OFF. The Toyota Dealer first said I needed two catalytic converters, then one. I spoke with a guy at a national auto parts store and he said he doubts it's the catalytic converter since the lights come-and-go. What should I do?
Submitted: 5 years ago.
Category: Toyota
Expert:  Toyota Service replied 5 years ago.

Toyota Service : Hello. Welcome to Just Answer. Please allow me to assist you. Do you have the results of a recent diagnostic scan available? Thanks
Customer:

no

Toyota Service : Then why did the dealer tell you you needed cats?
Toyota Service : What did he base his decision on?
Customer:

not sure. they checked it out and said so. might have done scans but I don't know exactly what they did.

Toyota Service : Ok.
Customer:

I keep all the paper work in the glove compartment. I can go check and see if they gave me scan results but I doubt it.

Toyota Service : For some reason, toyota lights up those three lights when there is a problem in the system, all 3 lights is normal, it indicates you have an issue.
Customer:

does it necessarily mean cats?

Toyota Service : A print out would be great, the DTCs specifically
Toyota Service : Not necessarily
Customer:

I'll check and be back in a few minutes. Can you hang on?

Toyota Service : Sure
Customer:

be right back

Toyota Service : Ok. Take your time.
Customer:

All I found was an invoice that said: "PO430 Tested EEC System. Cat Converters need to be replaced. E." They quote me some outrageous price - more than $2,000 if I remember correctly. I said I couldn't do that, then they started back-peddaling and said something about only needing one and the cost being less than $1,000. Didn't instill a lot of confidence.

Toyota Service : I agree. You don't tell a customer you need a 2 grand worth of cats, then change your tune when the customer balks at the prices.
Toyota Service : There are a few things that can trick the sensors into thinking the cats are compromised.
Toyota Service : When was the last time you had a good tuneup?
Customer:

It has 145K miles on it and I have taken it in pretty faithfully for 5K mile maintenance until they pulled this stunt. That was probably 10-15K miles ago, so I've done most everything recommened up until that time.

Toyota Service : You using genuine Toyota spark plugs?
Customer:

I've just been taking it into Valvoline for the 10 minute oil changes the past couple of times.

Customer:

Since the Toyota dealer did all the work up until recently I assume they are Toyota plugs.

Toyota Service : Ok
Toyota Service : Since the lights are intermittent, I would have to see more proof that the cats are bad. Bad cats don't get better. Bad cats get worse.
Customer:

So the lights would come on and stay on if the cats were bad?

Toyota Service : I just had a customer with a similar problem here an hour ago on a Tundra.
Toyota Service : Yes. On and stay on
Toyota Service : Before I even thought about cats, I would want to see the response of the sensors. If you have a faulty sensor, the cat code can be set. The lights blinking might be the beginnings of a bad sensor. To be certain, I would need to see some real time readouts.
Toyota Service : What I would do if I were you: see if you can find a fuel additive called "BG-44K". Fill the tank, pour the entire can into the tank, and drive it, run the fuel out as fast as you can. Then take it and get it rescanned. I use the BG product, it seems to improve cat performance by cleaning out the system. Def worth a try before I spent a grand on a unsupported guess.
Customer:

OK...I'll try that and if it doesn't help there's another Toyota dealer not too far from here and I can take it to them, not tell them about the earlier diagnosis and just see what they say. thanks for your time.

Toyota Service : Ok. You are welcome
Toyota Service : Thanks for choosing Just Answer today. I trust my input will be found to be beneficial. If so, please choose to accept my answer via the accept button on your screen. Thanks again.
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