2005 Prius - replacing catalytic converter at 85,000 miles

["toto princess"]

Am just past 85,000 miles on my 2005 Prius (I have a long commute...)

I bought my car in April 2005, absolutely LOVE it and have had no problems with it whatsoever until now.

I took it in today for routine service and inspection. Over the past couple of weeks, the "check engine" light has been coming on for short periods of time. It never stayed on and I knew it was time for service, so I figured I would get it checked when I went in. It came back on today before I went to the dealer.

They ran the computer and said that there were several "bugs" but that the real problem was the catalytic converter and that it needed to be replaced. The cost was approx $1,500. I have had all of my service done at this dealer, so they ended up offering to pay half of the total, so that I would pay approx $750 total for parts and labor. They are ordering the part so the work can be done next week. Of course my warranty for the catalytic converter is 8yrs/80,000, so no help there.

Is this a common problem? Is this a reasonable price? Any thoughts or suggestions?

The helpful folks at Prius Online suggested that the real problem might be a failing 12 v battery.

Can you suggest anything else I need to think about before I go back to the dealer?

I live in a small town where people aren't very comfortable with the Prius, so I have always taken it to the nearest dealer so a certified Prius technician could work on it. They have always been pleasant and helpful, but I have always paid for all of the extra service, etc., so they had no reason not to be! Perhaps they are being straight with me, but I don't feel very confident in their assessment and feel totally at their mercy...

Thanks for your help!

[dogfriend]

Do you know the actual codes that they pulled from your car? That might help with the assessment of whether the catalytic converter is actually bad or not.

I think it is unusual for a car with 85,000 to have a worn out converter, but it isn't out of the realm of possibility. When replacing the converter, they should check to make sure the engine control system is working properly and won't cause the next converter to fail too.

$1500 is a lot, but the Prius converter is different than a standard converter in shape and location, so part of the cost is due to the uniqueness of the part.

[Mouth]

$1500, no wonder people are stealing them out from under parked cars. Yikes! Hopefully the wizards on this site can save you some money and figure out what those expensive "bugs" are.

[galaxee]

i see you posted they did a fuel injector cleaning at 75k- that is probably too far in the past to be causative. well... it's a tough call, and you can't really prove it at this point. definitely not a failing 12v battery causing that code.

ask if they'll pick up the cost of the part if you'll pick up the rest of the cost (labor, shop fees, etc.) cats burning out in a prius are rare- they usually go because they're overworked or inundated with oil. the prius does neither.

ask for the old cat back from them and we'll give ya $20 for it. heck, we might even be able to pick it up since you're also in central nc.

["toto princess"]

Thanks for your input!

So could someone explain to me how the check-engine light works? I don't understand why it keeps going on and off. (It's off again today.)

I guess I would have thought if the catalytic converter was bad, the light would stay on. And I don't understand why the other codes don't matter. ("throttle actuator control sys - stuck open", "immobilizer malfunction", "solar sensor circuit (pass side)", "body ECU communication stop", "smart key ECU communication stop", and "combination meter ECU communication stop")

I think I am just frustrated with the dealership because I don't understand the situation. They are so into the "customer service" deal that I always feel "handled". I certainly understand why the technicians can't spend their day talking to the owners, but the customer service guys don't seem to know anything about my car, and i don't have any way of knowing if the technician does. I got the impression that the "head" of the shop was Prius certified, and that he would do the catalytic converter replacement, but does that mean he hasn't been doing all of my other work? and does that matter?

It seemed like they were so quick to decide it was the catalytic converter and then very quick to say they would pay half. It made me wonder. I feel like either I don't really need the catalytic converter replaced or else they looked at my records and saw what a good "sucker" I was to pay for all of the extra service and were afraid that might disappear. I guess it is sad that I am that suspicious, and can't trust that they might be trying to help me out...

Galaxee - if they replace the converter I will be happy to save the old one for you. I live down towards Charlotte (and go to the dealer in Concord)...

[dogfriend]

Originally Posted by "toto princess"

Thanks for your input!

So could someone explain to me how the check-engine light works? I don't understand why it keeps going on and off. (It's off again today.)

For some codes, the light will come on and stay on until the code is cleared. For other codes, the light will come on, but if the problem is not detected again within a certain time period (usually defined by the number of drive cycles) then the light will go off until the problem is detected again.

For your P0420 code, the test is run once per drive cycle (problem detected) and the MIL light (check engine light) will stay on for 2 drive cycles and then go off if the problem is not detected again.

Originally Posted by "toto princess"

I guess I would have thought if the catalytic converter was bad, the light would stay on. And I don't understand why the other codes don't matter. ("throttle actuator control sys - stuck open", "immobilizer malfunction", "solar sensor circuit (pass side)", "body ECU communication stop", "smart key ECU communication stop", and "combination meter ECU communication stop")

Your other problem codes could be actually problems, or they might be caused by someone who did not run the scan tool properly (e.g. didn't plug it into the DLC all the way) and got a communication error. You didn't post the actual code numbers, but all of the descriptions except for the first one are related to communication errors.

Originally Posted by "toto princess"

I think I am just frustrated with the dealership because I don't understand the situation. They are so into the "customer service" deal that I always feel "handled". I certainly understand why the technicians can't spend their day talking to the owners, but the customer service guys don't seem to know anything about my car, and i don't have any way of knowing if the technician does. I got the impression that the "head" of the shop was Prius certified, and that he would do the catalytic converter replacement, but does that mean he hasn't been doing all of my other work? and does that matter?

My dealership (that I bought my car from) works like this too. They only allow you to talk to the Service Advisor, not the actual tech that works on your car. And they take your car to the back of the facility, so you can't see if they are working on it or not. The Service Advisor I had was an idiot; he wasn't even a good liar, so I stopped taking my car to them.

[galaxee]

Originally Posted by "toto princess"

I guess I would have thought if the catalytic converter was bad, the light would stay on. And I don't understand why the other codes don't matter. ("throttle actuator control sys - stuck open", "immobilizer malfunction", "solar sensor circuit (pass side)", "body ECU communication stop", "smart key ECU communication stop", and "combination meter ECU communication stop")

well, its appearance depends on the usage patterns of the cat converter.

that throttle plate code is a problem. it could be that someone pushed the throttle butterfly open while the car was on and that registered as a code. it could be the throttle plate needs to be cleaned.

need to know the code number (letter and 4 numbers) for the immobilizer malfuction.

all those communication errors are common- nothing wrong there. also the solar sensor circuit. that means the car was indoors when they checked the codes.

It seemed like they were so quick to decide it was the catalytic converter and then very quick to say they would pay half. It made me wonder. I feel like either I don't really need the catalytic converter replaced or else they looked at my records and saw what a good "sucker" I was to pay for all of the extra service and were afraid that might disappear. I guess it is sad that I am that suspicious, and can't trust that they might be trying to help me out...

the diagnosis is pretty simple. that code means that the catalytic converter is bad, there is no arguing or discussion about that code. P0420 means cat converter.

they don't usually offer to pay half- which is why you can probably the cost of the part out of them if you pay for labor. they probably feel there's something they did to contribute to that- a little guilt about how they performed that fuel injection service maybe? :/ at any rate, get what you can out of em, you've been a good customer to them and they want to keep you.

Galaxee - if they replace the converter I will be happy to save the old one for you. I live down towards Charlotte (and go to the dealer in Concord)...

thanks!

[Patrick Wong]

Originally Posted by galaxee

...the diagnosis is pretty simple. that code means that the catalytic converter is bad, there is no arguing or discussion about that code. P0420 means cat converter...

Hi Galaxee,

Referring to the repair manual page that dogfriend posted above, note that the possible reasons for P0420 include an exhaust leak, a bad air/fuel ratio sensor upstream, a bad oxygen sensor downstream, or the catalytic converter. Also note that the catalytic converter is listed last.

Compare to my 2005 repair manual where the catalytic converter is first in the list of possible problems. I am wondering whether the editing on dogfriend's page was intended to discourage catalytic converter replacement prior to ruling out all other possible causes.

Hi toto princess,

It may be worth your while to inquire whether your tech followed the procedure to test the air/fuel ratio sensor and verified its proper operation. If that sensor had failed, its replacement would cost much less than the catalytic converter.

[dogfriend]

I think if the tech is thorough, they would look at the response of the downstream O2 sensor (voltage vs time) to see if it tracks with the upstream sensor or not. If it tracks the upstream sensor that would indicate that the cat is not working (that is what the ECU does when it runs the test). The ECU could get fooled by an exhaust leak or a bad O2 sensor, so the tech should rule those causes out.

Another test would be for the tech to put a probe in the tailpipe, essentially doing a smog test to see if the HC and NOx are elevated or not.

[dogfriend]

I am attaching all 7 pages for P0402 (don't tell Toyota). Basically the troubleshooting says to address any other codes first, rule out any exhaust leaks, then rule out a problem with the upstream sensor, then rule out a problem with the downstream sensor, if it isn't any of these, replace the cat.