Catalytic Converter

Certainly if your exhaust system is clogged, the car would make less power and get worse mileage.

I do not believe you can legally install a used catalytic converter in a car in the US but new units on ebay are under $300 (I am sure they are more locally)

Walker Direct Fit Catalytic Converter 16337 - eBay (item 330522254207 end time Feb-21-11 03:52:42 PST)

Any nearby garage would be able to install it for you, even if, as is likely, they do not stock them. (Walker is a good name in exhausts) http://www.walkerexhaust.com/catalog/ExhaustCouponScreen_49_State.asp?Coupon_ID1=16337

If you prefer DIY , I would buy a new gasket and 3 bolts/nuts at the dealer, and be prepared for a lot of rust.

After the converter is replaced, you may still need to go back to a Toyota dealer to clear the codes so the check engine light goes off.

Another one from a company I have never heard of 04 05 06 07 Toyota Prius 1.5L Main Catalytic Converter - eBay (item 190341378730 end time Feb-04-11 08:33:10 PST)

 

It would be best for you to replace the catalytic converter, if you don't wish to pollute the air unnecessarily. I suggest that you visit your local muffler shops to see what they can do for you regarding installation of an aftermarket unit. The original equipment catalytic converter probably is clogged with rust, which impairs engine performance.

I recommend that you perform the equivalent of the 100K and 120K mile services (which includes engine and inverter coolant replacement, iridium spark plug replacement, engine and cabin air filter replacement, and inspection of the chassis and brakes) unless you know for sure that the car was recently serviced to that full extent.

Regarding clearing the existing DTC codes, that can be easily done by disconnecting the 12V battery negative terminal for a few minutes. You may want to figure out how to do that to save yourself $100 at the dealer.

 

Yes, LA is the second least likely place to see a Prius in the US after MS.

Since you are new to LA, here is a site that recommends local mechanics, although your boy friend should be able to repair this with adult supervision. (you)

Car Talk | Mechanics Files

 

No, the Prius catalytic converter is the same in concept as any other car. If your BF has access to welding equipment and prior experience working on auto exhaust systems then you should be good to go.

Given your car's odometer reading, maybe your BF should start by replacing the air/fuel ratio sensor which is located upstream from the catalytic converter. If he is game, I recommend that you use the correct Toyota part instead of aftermarket. This is a much easier task than replacing the catalytic converter.

Then, if after the A/F ratio sensor is replaced, you still notice that your engine lacks performance, you can ask your BF to replace the catalytic converter.

 

Not that I am suggesting you do this, since it might cause the check engine light to stay on permanently, or maybe all kinds of other weird stuff. I have heard of people removing the CC altogether buy cutting it out and replacing the gap with a pipe, or removing the innards of the CC and only keeping the shell. Again, I have no idea how all the computerized gizmos will react to a missing part....

 

autobeyours.com. A shop will NOT install a used cat. But your boyfriend on the other hand, ...

 

As I recall, there are oxygen sensors just before and just after the catalytic converter. When they read the same value, then it's obvious that the catalytic converter isn't doing its job. The exit one should indicate that the exhaust is cleaner after passing through the converter.

I don't know how to sort out which components are causing the check engine light. But it seems possible that it could be the oxygen sensors and not the converter. On the other hand, we just replaced the converter on a BMW with 200,000+ miles and the hydrocarbon pollution when down by 90%.

 

Removing the cat completely will only make her problem worse. The check engine light will be on constantly because the emissions system will sense that the exhaust gasses are not being treated. That, and anyone behind her will have to put up with the stink of untreated exhaust.

 

I assume that you are going to ask your BF to do this work:

1. Replace the iridium spark plugs with the correct NGK or Denso plugs as specified in the owners manual.
2. Check the engine and cabin air filters and replace if dirty.
3. Replace the engine and inverter coolant (see my posts on how to do both.)
4. Inspect the brake and suspension systems. Very likely that the front struts and rear shocks need to be replaced. I've also posted on how to replace those. If it is necessary to replace the brake pads or shoes, disconnect the 12V battery before beginning work to avoid inducing DTC into the skid control ECU.

techinfo.toyota.com is the official source of Toyota repair manual info.

This is why I suggested replacing the air/fuel ratio sensor, which is located in the same spot as the first oxygen sensor would be in another vehicle (but has a fancier name and works slightly differently.)

 

Hate to be the one to rain on the parade here but I figured I would chime in before you waste money on an aftermarket cat. Aftermarket cats unfortunately don't seem to work on Toyota vehicles. I don't know if the programming of the car is just so sensitive or if the aftermarket cats just aren't good enough. Any car we've ever had a P0420 or P0430 and a customer has put on an aftermarket cat the vehicle has always returned the same DTC's after the Catalyst Monitor completes its check (this is of course after the original DTC's have been cleared). The catalyst monitor doesn't operate all the time. RPM, MPH, and throttle angle all have to stay in a certain range for X number of time for the monitor to run. So if you put an aftermarket cat on and clear the codes and they don't immediately come back on don't think your'e in the clear just yet. Just wanted to my $0.02 in from what I've seen.

 

Hi Josh,

Do you think that it would help if Melissa narrowed her selection criteria to choose from aftermarket catalytic converters certified for sale in California?

 

Does such an aftermarket product for the Prius even exist?

This is one of the unintended consequences of the Clean Air act, where a salvage cat from a low mileage car performs better with a longer expected lifespan than a brand new aftermarket replacement, but is technically illegal.

 

You could use an oscilloscope to look at the voltage waveform produced by the air/fuel ratio sensor upstream from the catalytic converter, and compare to the voltage waveform produced by the oxygen sensor which is downstream from the catalytic converter. You expect the former waveform to show rapid changes in voltage while the latter waveform would show relatively constant voltage.

The engine ECU does this comparison automatically, as these are some of the parameters that ECU is responsible for tracking.

Since you did not say that you have any DTC that show either part is bad, then you don't have to worry too much about this.

I recommend that you focus on getting the engine's responsiveness back to where it should be. If you agree, then I suggest that you start with replacing the iridium spark plugs and the air/fuel ratio sensor. Although the engine ECU did not identify the A/F ratio sensor as a failed part, over time the sensor loses its ability to track changes in the A/F ratio and the voltage changes become sluggish. This would impair engine performance and also might be part of the reason why the catalytic converter error code came up.

Also, check the engine air filter and replace that if it is dirty. Remove the air filter from the housing and hold up to the sun. If you don't see much light coming through, replace the filter. Compare to a new filter if necessary. When reinstalling the filter, note that the dirty side is face down and the rubber tab on the gasket fits into a corresponding space at the rear of the air cleaner housing.

Additional items: Clean the mass air flow sensor and the throttle body interior and throttle plate. Remove the MAF sensor from the air cleaner housing, then spray the two wires and the amber bulb with MAF sensor cleaner. Remove the air cleaner housing from the throttle body, apply throttle body cleaner to a clean cloth or paper towel, then scrub off the black gunk on the throttle body interior and throttle plate. You can rotate the spring-loaded shaft of the throttle plate in order to clean its edges and the underside.

Then, clear the existing DTC by disconnecting the 12V battery negative cable for 5 minutes. See how well the powertrain operates. If the engine performs well, then you don't have to worry about replacing the catalytic converter unless DTC P0420 comes back.

Yes, that Eastern catalytic converter looks good. Too bad Josh reported that it may not work as well as you might expect.

You can buy the correct catalytic converter for $1,186 plus shipping here:
Champion ToyotaWorld

However I recommend that you defer this purchase until you see what happens with the other engine work described above.

Excellent point. In the distant past I bought a replacement catalytic converter for my 1988 BMW 325i convertible, while living in Silicon Valley. However I just did a quick search and could not find any Prius catalytic converters for sale to CA residents, other than the correct Toyota part.